CN105510637B - Micro-/ nano thermoelectricity in-situ detector based on scanning probe microscopy and detection method - Google Patents

Abstract

The present invention provides a kind of micro-/ nano thermoelectricity in-situ detector based on scanning probe microscopy.The apparatus system is used with conductive, thermal conductivity probe, it is capable of providing the surface topography detection, electric signal detection and thermal signal detection mode of sample, by controlling displacement or the oscillation trajectory of probe, can in situ, synchronous, detection sample in real time electricity, hot property.Therefore, which, which overcomes existing scanning probe microscopy only, has the limitation of the electrically or thermally single detective function of signal；Simultaneously, can in situ, synchronous, detection material in real time temperature be distributed with thermal conductivity, electrical property and its Dynamic Evolution, to the Coupling Rule and mechanism between the intuitively magnetic heat of research material, help to reduce the power consumption of micro-/nano parts, improve its stability and integrated level, promote significantly it is micro-/receive the development of scale science of heat.

Description

Micro/nano pyroelectric in situ detection device and detection based on scanning probe microscope method

technical field

The application belongs to the technical field of signal detection, and in particular relates to a micro/nano pyroelectric in-situ detection device and detection method based on a scanning probe microscope, which can detect the electrical conductivity and thermal properties of micro-regions in situ, synchronously and in real time.

Background technique

In 1981, Binning et al. invented the scanning tunneling microscope (STM), for which they won the Nobel Prize in Physics. STM is based on the theory of tunneling effect in quantum mechanics. When the metal probe is close to the surface of a sample with good conductivity, a tunneling current will be generated between the metal probe and the sample under the action of bias voltage, and the magnitude of the current can accurately reflect the probe. The distance between the needle and the sample, so STM can image atomic-scale samples with a lateral resolution down to 0.1nm.

However, when using STM to characterize sample properties, the surface of the sample is required to have a certain conductivity, which limits its application field. Bing et al. subsequently developed the Scanning Probe Microscopy (SPM) technology, which can study the corresponding properties of the sample at the micro-nano scale by detecting the interaction between the sample and the SPM probe tip, thus promoting the performance of micro-nano materials characterization.

When using SPM to characterize the characteristics of the sample, the characteristics of different characteristics of the sample can be obtained according to the properties of the probe and the interaction between the probe and the sample. For example, when characterizing the conductivity of a sample, it is necessary to coat the surface of the probe with a metal conductive layer and be able to read the current under an applied voltage; while characterizing the magnetic properties of the sample, it is required that the surface of the probe be coated with a magnetic film, relying on the magnetic moment of the magnetic film The interaction with the magnetic moment of the sample characterizes the magnetic properties of the sample. Therefore, the performance of the probe largely determines the accuracy and reliability of sample property acquisition.

With the miniaturization and integration of electronic devices, the device size and device spacing have reached the micro/nano scale, and its heat generation and heat dissipation problems have become a bottleneck restricting further high integration. At the micro/nano scale, the microstructure and domain structure of materials have a particularly important impact on thermal properties. A microcrack, cavity, grain boundary, or even a domain wall may affect the thermal properties of a material. Taking multiferroic materials as an example, magnetic/electrical domain flipping (or domain wall movement) and leakage current driven by an external field will both cause micro-region heating. Therefore, characterizing heat-related physical properties at the micro/nano scale and understanding the physical processes of heat generation and heat dissipation have become a brand-new branch of modern thermal science—micro/nano-scale thermal science.

Therefore, it is extremely important to study the relationship between the surface morphology, thermal properties and electrical properties of related materials, especially micro-nano materials, for understanding their intrinsic properties, physical mechanisms of heat generation and heat dissipation, and for the development of related multifunctional materials. significance.

However, most of the current SPMs, such as conductive atomic force microscopy, can only characterize the morphology and/or electrical properties of samples independently, in real time, and ex situ, but cannot simultaneously characterize the morphology, electrical conductivity, and thermal properties. Therefore, how to characterize the morphology, electrical conductivity, and thermal properties of micro-nano materials in situ, synchronously, and in real time is one of the research topics for scientific and technological workers.

Contents of the invention

In view of the above technical problems, the present invention provides a signal detection device at the micro/nano scale, which can be used for synchronous, in situ and real-time monitoring of the surface morphology, thermal properties and electrical conductivity of materials at the micro/nano scale probing.

The technical solution adopted by the present invention to achieve the above technical purpose is: a micro/nano pyroelectric in-situ detection device based on a scanning probe microscope, the detection device includes the following:

(1) Scanning probe microscope platform, probe, probe control unit

Probe control unit: for driving or controlling the displacement and/or vibration of the probe;

Probe: has electrical conductivity and thermal conductivity;

The probe includes a probe arm and a needle tip;

(2) Shape detection platform

Including a displacement or vibration signal acquisition unit for receiving the displacement signal or vibration signal of the probe;

The probe scans the sample surface horizontally and directionally from the initial position. During the scanning process, the probe tip is controlled to be in point contact or vibration point contact with the sample surface. The displacement or vibration signal acquisition unit receives the longitudinal displacement signal or vibration signal of the probe tip. Analyze the shape signal of the sample;

(3) Thermal signal detection platform

Including thermal circuit and thermal signal acquisition unit;

In the thermal circuit, the electrical signal is excited by the electrical signal applying unit, and the electrical signal flows into the probe and heats the probe. The probe and the sample perform heat exchange, so that the voltage signal in the thermal circuit changes. Change to obtain the thermal signal of the sample;

(4) Electrical signal detection platform

Including electrical circuit and electrical signal acquisition unit;

In the electrical circuit, the electrical signal is excited by the electrical signal applying unit, and the electrical signal flows into the probe and the sample in turn, and the electrical signal of the sample is obtained through the electrical signal acquisition unit;

(5) Central control unit

It is used to initialize each unit of the system, control each unit of the system, receive the shape, heat, and electrical signals of the sample, and obtain the image of the shape, heat, and electrical signals of the sample after analysis.

Preferably, the scanning probe microscope platform is provided with a resistance heating stage for providing a variable temperature environment.

The present invention also provides a preferred probe structure. As shown in Figures 1 and 2, the probe includes a probe arm 1 and a needle point 2. The needle point 2 is composed of a needle point body 3 and a covering layer. Film one 4 on the surface, film two 5 on the surface of film one, and film three 6 on the surface of the film two; film one 4 has conductivity, film two 5 has electrical insulation, film three 6 has conductivity, film one 4 and film The materials of three 6 are different; and, film one 4, film two 5 and film three 6 form a thermocouple structure, that is: at the tip of the needle point body, the surface of film one 4 is film three 6, and the remaining parts except the tip of the body , film two 5 is located between film one 4 and film three 6 .

The material of the thin film-4 is not limited, including one material or a combination of two or more materials in metals and semiconductors with good electrical conductivity, such as bismuth (Bi), nickel (Ni), cobalt (Co), potassium ( K) and other metals and their alloys, at least one of semiconductors such as graphite and graphene.

The material of the thin film 25 is not limited, including semiconductors, inorganic materials or organic materials with certain insulating properties, such as zinc oxide (ZnO), bismuth ferrite (BiFeO ₃ ), lithium cobaltate (LiCoO ₂ ), nickel oxide ( NiO), cobalt oxide (Co ₂ O ₃ ), copper oxide (Cux O), silicon dioxide (SiO ₂ ), silicon nitride (SiN _{x )} , titanium dioxide (TiO ₂ ), tantalum pentoxide (Ta ₂ O ₅ ), niobium pentoxide (Nb ₂ O ₅ ), tungsten oxide (WO _x ), hafnium dioxide (HfO ₂ ), aluminum oxide (Al ₂ O ₃ ), carbon nanotubes, graphene, graphene oxide, non Crystalline carbon, copper sulfide ( _CuxS ), silver sulfide (Ag ₂ S), amorphous silicon, titanium nitride (TiN), polyimide (PI), polyamide (PAI), polyschiff base (PA ), polysulfone (PS) and the like.

The material of the thin film 36 is not limited, and includes one material or a combination of two or more materials among metals and semiconductors with good electrical conductivity. The metals and semiconductors with good electrical conductivity include but not limited to bismuth, nickel, cobalt, potassium and other metals and their alloys, and at least one of semiconductors such as graphite and graphene.

The thermocouple structure composed of the first film, the second film and the third film can be obtained by the following preparation method:

Step 1. Prepare thin film-4 on the surface of the tip body by coating;

Step 2, using the coating method to prepare film two 5 on the surface of film one 4;

Step 3, using an etching method to remove the film 2 5 at the tip of the needle tip body, exposing the film 1 4;

Step 4. Prepare thin film 3 6 on the surface of thin film 1 exposed in step 3 by coating method, so that thin film 4 and thin film 3 6 are connected at the tip of the needle tip to form a thermocouple structure.

In the above-mentioned preparation method, the coating method in steps 1, 2, and 4 includes but is not limited to one of various solution spin coating methods, inkjet printing, solid sputtering, thermal evaporation, electron beam evaporation, etc. Or a combination of two or more; the method for removing the tip thin film 2 in step 3 includes but is not limited to dry etching, wet etching and other methods, such as ion etching, reactive ion etching, chemical etching and the like.

As shown in Figure 3, the thermocouple structure formed by the thin film one 4, the thin film two 5 and the thin film three 6 can also be obtained by another preparation method as follows:

Step 1. Using the coating method, film one 4, film two 5 and film three 6 are sequentially prepared on the surface of the needle tip body 3;

Step 2. Apply a voltage between the film 3 6 and the electrode layer 7, and use the tip discharge principle to adjust the distance between the film 3 6 and the electrode layer 7 to melt the film 3 6 at the tip of the needle point, exposing the film 2 5, and Other parts of the film 36 are not melted;

Step 3: remove the exposed film 2 5 described in step 2, and expose the film 1 4;

Step 4: Coating the exposed part with the same material as thin film three 6, so that thin film one 4 and thin film three 6 are connected at the tip of the needle tip to form a thermocouple structure.

In the above-mentioned preparation method, the coating method in steps 1 and 4 includes but is not limited to one or both of various solution spin coating methods, inkjet printing, solid sputtering, thermal evaporation or electron beam evaporation. more than one combination.

When the above-mentioned probe with a thermocouple structure is used, the working mode of the nano-thermoelectric in-situ detection device based on the scanning probe microscope of the present invention includes the following two types, which are respectively used to detect the morphology, electrical signal, and thermal signal of the sample:

(1) Mode 1: used to detect the surface morphology and electrical signal of the sample

The probe drive unit drives the probe to move to an initial position on the sample surface. From the initial position, the probe conducts a directional scan on the sample surface along the transverse direction. The application unit, film 1, film 3 and the sample form a closed electrical circuit; the displacement or vibration signal acquisition unit receives the longitudinal displacement signal or vibration signal of the probe tip, and analyzes the shape signal of the sample through the central control unit; at the same time, the electrical signal The application unit applies an electrical signal to the needle tip, and the electrical signal flows into the first film, the third film and the sample to form a voltage signal, the electrical signal of the sample is obtained through the electrical signal acquisition unit, and the electrical signal image of the sample is obtained through analysis by the central control unit.

(2) Mode 2: used to detect the thermal signal of the sample

The electrical signal application unit, film 1, and film 3 form a closed thermoelectric circuit; the probe driving unit drives the probe to a certain position on the sample surface, so that the needle tip is in contact with the sample surface, and the electrical signal application unit applies an electrical signal to the needle tip, and the current flows into the The needle tip is heated, and the needle tip and the sample perform heat exchange, so that a voltage signal is generated in the thermal circuit, the thermal signal of the sample is obtained through the thermal signal acquisition unit, and the thermal signal image of the sample is obtained through the analysis of the central control unit.

When the probe with the above-mentioned thermocouple structure is used, the method for in-situ, synchronous and real-time detection of the morphology, electrical properties and thermal properties of the sample using the nano-thermoelectric in-situ detection device based on the scanning probe microscope of the present invention is as follows:

Step 1: The sample is fixed on the scanning probe microscope platform, using the above-mentioned detection mode 1, the probe is displaced to the initial position, and the sample surface is directional scanned along the lateral direction to obtain the topography image and electrical signal image of the sample;

Step 2: The probe is moved to the initial position in step 1, and the above-mentioned detection mode 2 is used to scan the surface of the sample horizontally and directionally as described in step 1 to obtain the thermal signal image of the sample.

The present invention also proposes another preferred probe structure. In this structure, as shown in FIG. 1 , the probe includes a probe arm 1 and a needle tip 2 . As shown in Figure 4, the needle point 2 includes a needle point body 3, a thermal resistance material layer 8, a first conductive layer 9 and a second conductive layer 10; the thermal resistance material layer 8 is located on the surface of the needle point body 3, and the second conductive layer 10 is located on the surface of the thermal resistance The surface of the material layer; the first conductive layer 9 communicates with the thermal resistance material layer 8; the thermal resistance material layer 8 is made of a thermal resistance material, and is used to detect the temperature change and thermal conductivity of the sample; the first conductive layer 9 is made of a conductive material, and The thermal resistance material is connected to detect the change of the resistance value of the thermal resistance material; the second conductive layer 10 is made of conductive material.

The material of the thermal resistance material layer 8 is not limited, including silicon with low doping, semiconductor and metal resistance materials.

The material of the first conductive layer 9 is not limited, including one material or a combination of two or more materials in metals and semiconductors with good electrical conductivity, such as bismuth (Bi), nickel (Ni), cobalt (Co), At least one of metals such as potassium (K) and alloys thereof, and semiconductors such as graphite and graphene.

The material of the second conductive layer 10 is not limited, including one material or a combination of two or more materials in metals and semiconductors with good electrical conductivity, such as bismuth (Bi), nickel (Ni), cobalt (Co), At least one of metals such as potassium (K) and alloys thereof, and semiconductors such as graphite and graphene.

The preparation method of above-mentioned probe is as follows:

Step 1. Prepare a thermal resistance material layer 8 on the surface of the tip body by coating;

Step 2. Prepare the first conductive layer 9 on the surface of the tip body by coating;

Step 3. Prepare the second conductive layer 10 on the surface of the thermal resistance material layer 8 by coating.

In the above-mentioned preparation method, the coating methods in the steps 1, 2, and 3 include but are not limited to various solution spin coating methods, inkjet printing, etching, solid sputtering, thermal evaporation, electron beam evaporation, etc. one or a combination of two or more.

Preferably, the thickness of the thermal resistance material layer 8 is 0.1 μm˜10 μm.

Preferably, the thickness of the first conductive layer 9 is 0.1 μm˜1 μm.

When the above-mentioned probe with a thermal resistance structure is used, the working mode of the nano-thermoelectric in-situ detection device based on the scanning probe microscope of the present invention includes the following two types, which are respectively used to detect the morphology, electrical signal, and thermal signal of the sample:

(1) Mode 1: used to detect the surface morphology and electrical signal of the sample

The probe drive unit drives the probe to move to an initial position on the sample surface. From the initial position, the probe conducts a directional scan on the sample surface along the transverse direction. The application unit, the first conductive layer, the thermal resistance material layer and the second conductive layer form a closed electrical circuit; the displacement or vibration signal acquisition unit receives the longitudinal displacement signal or vibration signal of the probe tip, and the shape of the sample is obtained through the analysis of the central control unit. At the same time, the electrical signal applying unit applies an electrical signal to the needle tip, and the electrical signal flows into the first conductive layer, the thermal resistance material layer, the second conductive layer and the sample to form a voltage signal, and the electrical signal of the sample is obtained through the electrical signal acquisition unit , the electrical signal image of the sample is obtained through analysis by the central control unit;

(2) Mode 2: used to detect the thermal signal of the sample

The electrical signal application unit, the first conductive layer and the thermal resistance material layer form a closed loop; the electrical signal application unit heats the thermal resistance material layer, and then heats the probe tip, so that the temperature of the probe tip is different from the temperature of the sample ( Generally, a temperature higher than that of the sample is selected); the probe driving unit drives the probe tip to contact the sample, and heat exchange occurs between the sample and the probe tip, which in turn affects the temperature of the thermal resistance material layer. Due to the thermal resistance effect, the thermal resistance material The resistance value of the layer changes, and after being collected by the thermal signal acquisition unit, it is analyzed by the central control unit to obtain the thermal signal image of the sample.

In the above structure, the thermal resistance material layer and the second conductive layer are stacked at the tip of the needle tip body. Considering the actual preparation process, because the tip of the needle tip body has a small cross-section, it is difficult to prepare the covering layer, especially the preparation The multi-layer laminated structure is more difficult, so preferably, the second conductive layer is integrated in the thermal resistance material layer.

As another preferred structure, an insulating layer is provided between the resistive material layer and the second conductive layer to electrically insulate the resistive material layer from the second conductive layer, and the first conductive layer and the second conductive layer are electrically insulated. electrical connection. In this structure, when the above-mentioned mode 1 is used to detect the electrical signal of the sample, the electrical signal applying unit, the first conductive layer and the second conductive layer form a closed electrical circuit, the electrical signal applying unit applies an electrical signal to the needle tip, and the electrical signal flows into The first conductive layer, the second conductive layer and the sample form a voltage signal, the electrical signal of the sample is obtained through the electrical signal acquisition unit, and the electrical signal image of the sample is obtained through the analysis of the central control unit.

When the probe with the above-mentioned thermal resistance structure is used, the method for in-situ, synchronous and real-time detection of the electrical and thermal properties of the sample by using the nano-thermoelectric in-situ detection device based on the scanning probe microscope of the present invention is as follows:

Step 1: The sample is fixed on the scanning probe microscope platform, using the above-mentioned detection mode 1, the probe is displaced to the initial position, and the sample surface is directional scanned along the lateral direction to obtain the topography image and electrical signal image of the sample;

Step 2: The probe is moved to the initial position in step 1, and the above-mentioned detection mode 2 is used to scan the surface of the sample horizontally and directionally as described in step 1 to obtain the thermal signal image of the sample.

The present invention also provides a preferred probe control unit structure, as shown in FIG. 5 , the probe control unit is a piezoelectric driver connected with the probe. At this time, the displacement signal acquisition unit includes a light source, a photoelectric four-quadrant detector and a signal processor; in the working state, the sample is placed on the platform of the scanning probe microscope, the probe vibrates under the action of the piezoelectric driver, and the light source illuminates the probe. The needle arm, the reflected signal is collected by the photoelectric four-quadrant detector, and then connected with the central control unit after being processed by the signal processor.

As an implementation manner, as shown in FIG. 5 , the signal processor includes a front-end amplifier, an integrator, a high-voltage amplifier, a delayer, a lock-in amplifier, and a back-end amplifier. The photoelectric four-quadrant detector is connected to the integrator through the front-end amplifier, and the integrator is connected to the high-voltage amplifier. One signal of the high-voltage amplifier is fed back to the piezoelectric driver to form a closed-loop control. The other signal is connected to the delayer, and the delayer It is connected with the 1ω (one times frequency channel) and 3ω (three times frequency channel) channels of the lock-in amplifier, the lock-in amplifier is connected with the back-end amplifier, and the back-end amplifier is connected with the control center.

As an implementation manner, as shown in FIG. 5 , the thermal signal acquisition unit includes a delayer, a lock-in amplifier and a back-end amplifier.

In summary, the nano-thermoelectric in-situ detection device based on the scanning probe microscope provided by the present invention has the following advantages:

(1) Existing detection devices based on scanning probe microscopes only have the detection function of electrical or thermal signals. The present invention breaks through the limitation of the detection function and provides the detection function of electrical signals and thermal signals;

(2) By applying electric field and temperature field in situ, it is possible to simulate the actual service environment, realize in situ excitation of thermal/electrical domain inversion, introduction of leakage current, etc. under the excitation or action of multiple physical fields, and realize in situ, synchronous and real-time The temperature and thermal conductivity distribution of materials and their dynamic evolution process can be detected accurately, so the coupling law and mechanism between electricity and heat of materials can be studied in situ and intuitively.

Therefore, the present invention expands the function of the scanning probe microscope, not only provides an advanced detection platform for the research of thermoelectric functional materials and devices, thereby providing help for reducing the power consumption of micro/nano devices and improving their stability and integration , and will also greatly promote the development of micro/nanoscale thermal science.

Description of drawings

Fig. 1 is the top view structure schematic diagram of the probe with thermocouple structure in the nano-thermoelectric in situ detection device based on scanning probe microscope of the present invention;

Figure 2 is an enlarged view of the probe tip with a thermocouple structure in Figure 1;

Fig. 3 is a schematic diagram of the probe tip with thermocouple structure prepared in Fig. 1 by tip discharge melting method;

Fig. 4 is a schematic diagram of the probe tip structure with a thermal resistance structure in the nano-thermoelectric in-situ detection device based on the scanning probe microscope of the present invention;

Fig. 5 is a schematic diagram of a preferred functional structure of the nano-pyroelectric in-situ detection device based on the scanning probe microscope of the present invention.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments. It should be noted that the following embodiments are intended to facilitate the understanding of the present invention, but do not limit it in any way.

Among them: 1-probe arm, 2-needle tip, 3-needle tip body, 4-thin film one, 5-thin film two, 6-thin film three, 7-electrode layer, 8-thermal resistance material layer, 9-first conductive layer , 10 - the second conductive layer.

Example 1:

In this embodiment, the nano-thermoelectric in-situ detection device based on the scanning probe microscope includes a scanning probe microscope platform, a probe, a probe control unit, a shape signal detection platform, an electrical signal monitoring platform, a thermal signal detection platform, and a center control unit.

The probe control unit is used to drive or control the probe to perform displacement and/or vibration;

The topography signal detection platform includes a displacement or vibration signal acquisition unit, which is used to receive the displacement signal or vibration signal of the probe;

The electrical signal detection platform includes an electrical circuit and an electrical signal acquisition unit; the electrical circuit is stimulated by an electrical signal application unit to stimulate the electrical signal, and the electrical signal flows into the probe and the sample in turn, and the electrical signal of the sample is obtained through the electrical signal acquisition unit;

The thermal signal detection platform includes a thermal circuit and a thermal signal acquisition unit; the thermal circuit excites the electrical signal by the electrical signal application unit, and the electrical signal flows into the probe and heats the probe, and the probe and the sample perform heat exchange, so that the thermal circuit The voltage signal changes, and the thermal signal of the sample is obtained through collection;

The central control unit is used to initialize each unit of the system, control each unit of the system, receive the morphology, electrical and thermal signals of the sample, and obtain the morphology, electrical and thermal signal images of the sample after analysis.

As shown in FIG. 1 , the probe includes a probe arm 1 and a needle tip 2 .

The structure of the needle tip 2 is shown in FIG. 2 . It is composed of the needle tip body 3 and the surface covering layer. The surface covering layer consists of film one 4 , film one 4 , film two 5 , film two 5 and film three 6 . Thin film one 4 has electrical conductivity, thin film two 5 has electrical insulation, and thin film three 6 has electrical conductivity, and the materials of thin film one 4 and thin film three 6 are different; and thin film one 4, thin film two 5 and thin film three 6 form a thermocouple structure , that is: at the tip position of the needle point body 3, the surface of the film one 4 covers the film three 6, and the other parts of the needle point body 3 except the tip, the film two 5 is located between the film one 4 and the film three 6.

The probe tip with a thermocouple structure can be prepared by the following method, which includes the following steps:

Step 1. Prepare a thin film-4 on the surface of the needle tip body 3 by a coating method, such as solution spin coating, inkjet printing, solid sputtering, thermal evaporation, or electron beam evaporation;

Step 2, using methods such as solution spin coating, inkjet printing, solid sputtering, thermal evaporation, or electron beam evaporation to prepare a thin film 25 on the surface of the tip body 3 by using a coating method;

Step 3, using methods such as dry etching and wet etching, such as ion etching, reactive ion etching, chemical etching, etc., to remove the film 2 5 at the tip of the needle tip body 3, exposing the film 1 4;

Step 4. Prepare a thin film 36 on the surface of the tip body 3 by methods such as solution spin coating, inkjet printing, solid sputtering, thermal evaporation, or electron beam evaporation, so that the thin film at the tip of the tip body 3 The surface of 4 is covered with film three 6, except for the tip, film two 5 is located between film one 4 and film three 6.

The material of film one 4 is conductive metal Pt with a thickness of 100nm, the material of film two 5 is insulating layer Al ₂ O ₃ with a thickness of 200nm, and the material of film three 6 is conductive metal Ni with a thickness of 100nm.

The probe control unit uses a piezoelectric driver connected to the probe. The piezoelectric driver is an MFP-3D-SA-SCANNER scanner produced by Asylum Research Company of the United States, and the scanning range is X×Y=90×90 μm ² .

As shown in Figure 5, the displacement or vibration signal acquisition unit includes a light source, a photoelectric four-quadrant detector and a signal processor. The signal processor consists of a front-end amplifier, an integrator, a high-voltage amplifier, a delayer, a lock-in amplifier and a back-end amplifier. In the working state, the sample is placed on the scanning probe microscope platform, the probe vibrates under the action of the piezoelectric driver, the light source illuminates the probe arm, the reflected signal is collected by the photoelectric four-quadrant detector, and then connected to the integrator through the front-end amplifier. The integrator is connected to the high-voltage amplifier, and one signal of the high-voltage amplifier is fed back to the piezoelectric driver to form a closed-loop control, and the other signal is connected to the delayer, and the delayer is connected to the lock-in amplifier's 1ω (one frequency channel) and 3ω (triple frequency channel) channels are connected, the lock-in amplifier is connected with the back-end amplifier, and the back-end amplifier is connected with the control center.

The control center is composed of a computer, an initialization module and a control module.

The thermal signal acquisition unit is composed of a delayer, a lock-in amplifier and a back-end amplifier. The electrical signal acquisition unit is composed of a delayer, a lock-in amplifier and a back-end amplifier. In this embodiment, the thermal signal acquisition unit, the electrical signal acquisition unit and the signal processor are integrated.

The electrical signal applying unit in the thermal circuit is a current source.

The electrical circuit consists of an electrical signal applying unit as a voltage source.

In this embodiment, the Fe film grown on the ferroelectric substrate PMN-PT is selected as the research sample, and the thickness of the sample is 90 nm.

Using the above-mentioned nano-thermoelectric in-situ detection device based on scanning probe microscope, the method of in-situ, synchronous and real-time detection of the thermal properties of the sample at room temperature is as follows:

(1) The sample is fixed on the scanning probe microscope platform, and the initial parameters of each unit of the system are set through the initialization module;

(2) Under the action of the control module, the piezoelectric driver drives the probe to move to an initial position on the sample surface, the light source illuminates the probe arm, and the reflected signal is collected by a photoelectric four-quadrant detector; Carry out directional scanning, during the scanning process, the film 3 6 on the surface of the probe tip 2 is controlled to be in point contact or vibrating point contact with the sample surface; at the same time, the current source, film 1 4, film 3 6 and the sample form a closed electrical circuit;

The reflected signal is collected by a photoelectric four-quadrant detector, and then connected to the integrator through the front-end amplifier. The integrator is connected to the high-voltage amplifier. One signal of the high-voltage amplifier is fed back to the piezoelectric driver to form a closed-loop control. The delayer is connected with the 1ω (one frequency channel) and 3ω (triple frequency channel) channels of the lock-in amplifier, the lock-in amplifier is connected with the back-end amplifier, and the back-end amplifier is connected with the computer. After analysis After processing, the topography signal image of the sample is obtained; at the same time, the current source applies an electrical signal to the probe, and the electrical signal flows into the film 1 4, film 3 6 and the sample, and then flows into the ground to form a voltage signal. The signal is collected and delayed. The amplifier, the lock-in amplifier and the back-end amplifier are connected with the computer, and the electrical signal image of the sample at the position is obtained after analysis and processing;

(3) The piezoelectric driver drives the probe back to the initial position described in step (2) and lifts up a certain distance, and scans the sample surface again according to the lateral orientation described in step (2). During the scanning process, the probe is controlled. The thin film 36 on the surface of the needle tip 2 performs longitudinal displacement or vibration along the topography image obtained in step (2), the displacement or vibration signal acquisition unit receives the longitudinal displacement signal or vibration signal of the probe tip, and the reflected signal passes through the photoelectric four-quadrant detector Collect, then as described in step (1), connect with computer through front-end amplifier, integrator, high-voltage amplifier, delayer, lock-in amplifier, back-end amplifier, obtain the electric signal image of sample after analyzing and processing;

(4) The piezoelectric driver drives the probe back to the initial position described in step (2);

(5) Make the film 3 6 on the surface of the needle tip 2 contact the sample surface; the current source, the film 1 4 and the film 3 6 form a closed thermoelectric circuit; the current source applies an electrical signal to the probe, and the current flows into the needle tip 2 and performs Heating, heat exchange between the needle tip 2 and the sample, so that the voltage signal in the thermal circuit changes, the signal is collected, and connected to the computer through the delayer, lock-in amplifier and back-end amplifier, and the sample at the position is obtained after analysis and processing thermal signature image;

(6) According to the lateral direction described in step (2), the piezoelectric driver drives the probe to the next position;

(7) Steps (5) and (6) are repeated for each point until the sample surface is scanned point by point according to the transverse direction described in step (2).

Example 2:

In this embodiment, the nano-pyroelectric in-situ detection device based on the scanning probe microscope is exactly the same as that in Embodiment 1.

The difference is that the probe tip with a thermocouple structure is prepared by another method, which includes the following steps:

Step 1. Using the coating method, film one 4, film two 5 and film three 6 are sequentially prepared on the surface of the needle tip body 3;

Step 2. Apply a voltage between the film 3 6 and the electrode layer 7, and use the tip discharge principle to adjust the distance between the film 3 6 and the electrode layer 7 to melt the film 3 6 at the tip of the needle point, exposing the film 2 5, and Other parts of the film 36 are not melted;

Step 3: remove the exposed film 2 5 described in step 2, and expose the film 1 4;

Step 4: Coating the exposed part with the same material as thin film three 6, so that thin film one 4 and thin film three 6 are connected at the tip of the needle tip to form a thermocouple structure.

The method for in-situ, synchronous and real-time detection of the electrical and thermal properties of the sample at room temperature using the nano-pyroelectric in-situ detection device based on the scanning probe microscope is exactly the same as that in Example 1.

Example 3:

In this embodiment, the structure of the nano-thermoelectric in-situ detection device based on the scanning probe microscope is basically the same as that in Embodiment 1, except that a probe with a thermal resistance structure is used.

As shown in FIG. 1 , the probe includes a probe arm 1 and a needle tip 2 . As shown in Figure 4, the needle point 2 includes a needle point body 3, a thermal resistance material layer 8, a first conductive layer 9 and a second conductive layer 10; the thermal resistance material layer 8 is located on the surface of the needle point body 3, and the second conductive layer 10 is located on the surface of the thermal resistance The surface of the material layer; the conductive layer 9 is in electrical communication with the thermal resistance material layer 8 .

The material of the thermal resistance material layer 8 is low-doped silicon with a thickness of 2m, and the material of the conductive layer 9 is one of bismuth (Bi), nickel (Ni), cobalt (Co), potassium (K), graphite, and graphene , the thickness is 1 μm, the material of the second conductive layer 10 is one of bismuth (Bi), nickel (Ni), cobalt (Co), potassium (K), graphite and graphene, and the thickness is 0.1 μm.

The preparation method of above-mentioned probe is as follows:

Step 1. Prepare a thermal resistance material layer 8 on the surface of the needle tip body by coating methods such as solution spin coating, inkjet printing, etching, solid sputtering, thermal evaporation, and electron beam evaporation;

Step 2. Prepare the first conductive layer 9 on the surface of the needle tip body by coating methods such as solution spin coating, inkjet printing, etching, solid sputtering, thermal evaporation, and electron beam evaporation. The conductive layer and the thermal resistance material layer 8 Connected;

Step 3. Prepare the second conductive layer 10 on the surface of the thermal resistance material layer 8 by using coating methods such as solution spin coating, inkjet printing, etching, solid sputtering, thermal evaporation, and electron beam evaporation.

Using the above-mentioned nano-thermoelectric in-situ detection device based on the scanning probe microscope, the method of in-situ, synchronous and real-time detection of the electrical and thermal properties of the sample at room temperature is as follows:

(1) The sample is fixed on the scanning probe microscope platform, and the initial parameters of each unit of the system are set through the initialization module;

(2) Under the action of the control module, the piezoelectric driver drives the probe to move to an initial position on the sample surface, the light source illuminates the probe arm, and the reflected signal is collected by a photoelectric four-quadrant detector; Carry out directional scanning, during the scanning process, the second conductive layer 10 on the surface of the control probe tip 2 is in point contact or vibration point contact with the sample surface; at the same time, the current source, the first conductive layer 9, the thermal resistance material layer 8, the second conductive layer 10 and the sample form a closed electrical loop;

The reflected signal is collected by a photoelectric four-quadrant detector, and then connected to the integrator through the front-end amplifier. The integrator is connected to the high-voltage amplifier. One signal of the high-voltage amplifier is fed back to the piezoelectric driver to form a closed-loop control. connected, the delayer is connected with the 1ω (one frequency channel) and 3ω (triple frequency channel) channels of the lock-in amplifier, the lock-in amplifier is connected with the back-end amplifier, and the back-end amplifier is connected with the computer. After analysis After processing, the topography signal image of the sample is obtained; at the same time, the current source applies an electrical signal to the probe, and the electrical signal flows into the first conductive layer 9, the thermal resistance material layer 8, the second conductive layer 10 and the sample, and then flows into the ground, forming The voltage signal is collected, and connected to the computer through the delayer, lock-in amplifier and back-end amplifier, and the electrical signal image of the sample at the position is obtained after analysis and processing;

(3) The piezoelectric driver drives the probe back to the initial position described in step (2);

(4) The second conductive layer 10 on the surface of the needle tip 2 is brought into contact with the sample surface; the current source, the first conductive layer 9 and the thermal resistance material layer 8 form a closed thermoelectric circuit; the electrical signal application unit conducts the thermal resistance material layer 8 Heating, and then heating the probe tip, so that the temperature of the probe tip is higher than the temperature of the sample; the probe driving unit drives the probe tip to contact the sample, and heat exchange occurs between the sample and the probe tip, which affects the thermal resistance material The temperature of layer 8, due to the thermal resistance effect, makes the resistance value of the thermal resistance material layer 8 change, collects the signal, connects with the computer through the delayer, lock-in amplifier and back-end amplifier, and obtains the position after analysis and processing The thermal signature image of the sample;

(5) According to the lateral direction described in step (2), the piezoelectric driver drives the probe to the next position;

(6) Steps (4) and (5) are repeated for each point until the sample surface is scanned point by point according to the transverse direction described in step (2).

Example 4:

In this embodiment, the nanometer pyroelectric in-situ detection device based on the scanning probe microscope is basically the same as that in Embodiment 3, except that the second conductive layer 10 is integrated in the thermal resistance material layer 8 .

The embodiments described above have described the technical solutions of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the present invention. All done within the principle scope of the present invention Any modification, supplement or substitution in a similar manner shall be included within the protection scope of the present invention.

Claims (11)

1. A micro/nano pyroelectric in-situ detection device based on a scanning probe microscope, which is used to detect the surface morphology, thermal properties and electrical conductivity of a sample, characterized in that it includes the following: (1) Scanning probe microscope platform, probe, probe control unit Probe control unit: for driving or controlling the displacement and/or vibration of the probe; Probe: has electrical conductivity and thermal conductivity; The probe includes a probe arm and a needle tip; (2) Shape detection platform Including a displacement or vibration signal acquisition unit for receiving the displacement signal or vibration signal of the probe; The probe scans the sample surface horizontally and directionally from the initial position. During the scanning process, the point contact between the probe tip and the sample surface is controlled. The displacement or vibration signal acquisition unit receives the longitudinal displacement signal or vibration signal of the probe tip, and the sample is obtained through collection and analysis. topography signal; (3) Thermal signal detection platform Including thermal circuit and thermal signal acquisition unit; In the thermal circuit, the electrical signal is excited by the electrical signal applying unit, and the electrical signal flows into the probe and heats the probe. The probe and the sample perform heat exchange, so that the voltage signal in the thermal circuit changes. Change to obtain the thermal signal of the sample; (4) Conductive signal detection platform Including electrical circuit and electrical signal acquisition unit; In the electrical circuit, the electrical signal is excited by the electrical signal applying unit, and the electrical signal flows into the probe and the sample in turn, and the conductive signal of the sample is obtained through the electrical signal acquisition unit; (5) Central control unit It is used to initialize each unit of the system, control each unit of the system, receive the shape, heat, and conduction signal of the sample, and obtain the image of the shape, heat, and conduction signal of the sample after analysis. 2. The micro/nano pyroelectric in-situ detection device based on scanning probe microscope according to claim 1, characterized in that: the probe control unit is a piezoelectric driver connected to the probe arm; The displacement or vibration signal acquisition unit includes a light source, a photoelectric four-quadrant detector and a signal processor; In the working state, the sample is placed on the platform of the scanning probe microscope, the probe is displaced or vibrated under the action of the piezoelectric driver, the light source irradiates the probe arm, and the reflected signal is collected by the photoelectric four-quadrant detector, and then processed by the signal processor with connected to the central control unit. 3. The micro/nano pyroelectric in-situ detection device based on scanning probe microscope as claimed in claim 2, characterized in that: said signal processor includes a front-end amplifier, an integrator, a high-voltage amplifier, a time delay device, a phase-locked Amplifier and back-end amplifier; the photoelectric four-quadrant detector is connected to the integrator through the front-end amplifier, and the integrator is connected to the high-voltage amplifier. One signal of the high-voltage amplifier is fed back to the piezoelectric driver to form a closed-loop control, and the other signal is connected to the delayer. The delayer is connected with the double frequency channel and the triple frequency channel of the lock-in amplifier, the lock-in amplifier is connected with the back-end amplifier, and the back-end amplifier is connected with the central control unit. 4. The scanning probe microscope-based micro/nano pyroelectric in-situ detection device according to claim 1, characterized in that: the thermal signal acquisition unit includes a delayer, a lock-in amplifier and a back-end amplifier. 5. The micro/nano pyroelectric in-situ detection device based on scanning probe microscope according to any one of claims 1 to 4, characterized in that: the probe comprises a probe arm and a needle point, and the needle point consists of a needle point The main body and the cover layer are composed of film one on the surface of the needle tip body, film two on the surface of film one, and film three on the surface of film two; film one is conductive, film two is electrically insulating, and film three is conductive , the materials of film 1 and film 3 are different; and, film 1, film 2 and film 3 form a thermocouple structure. 6. The micro/nano thermoelectric in-situ detection device based on scanning probe microscope as claimed in claim 5, characterized in that: the thermocouple structure composed of the first thin film, the second thin film and the third thin film is obtained by the following preparation method: Step 1. Prepare thin film 1 on the surface of the needle tip body by coating method; Step 2, using the coating method to prepare film 2 on the surface of film 1; Step 3, using an etching method to remove film 2 at the tip of the needle tip body to expose film 1; Step 4, using the coating method to prepare film three on the surface of film one exposed in step 3, so that film one and film three are connected at the tip of the needle tip to form a thermocouple structure; Alternatively, the thermocouple structure composed of the first film, the second film and the third film is obtained by the following preparation method: Step 1. Using the coating method, film 1, film 2 and film 3 are sequentially prepared on the surface of the needle tip body; Step 2. Apply a voltage between the film 3 and the electrode layer. Using the principle of tip discharge, by adjusting the distance between the film 3 and the electrode layer, the film 3 at the tip of the needle point is melted to expose the film 2, while other parts of the film 3 are not melted. ; Step 3: removing the film 2 exposed in the step to expose the film 1; Step 4: Coating the exposed part of the first film with the same material as that of the third film by using the method of coating, so that the first film and the third film are connected at the tip of the needle tip to form a thermocouple structure. 7. The micro/nano pyroelectric in-situ detection device based on scanning probe microscope according to claim 6, characterized in that: it includes the following two detection modes: (1) Mode 1: used to detect the surface morphology and conductive signal of the sample The probe driving unit drives the probe to move to an initial position on the sample surface, and the probe scans the sample surface in a transverse direction from the initial position. During the scanning process, the probe tip is controlled to make point contact with the sample surface. 1. The thin film and the sample form a closed electrical circuit; the displacement or vibration signal acquisition unit receives the longitudinal displacement signal or vibration signal of the probe tip, and the shape signal of the sample is obtained through the analysis of the central control unit; at the same time, the electrical signal applying unit An electrical signal is applied, and the electrical signal flows into the first film, the third film and the sample to form a voltage signal, and the conductive signal of the sample is obtained through the electrical signal acquisition unit, and the conductive signal image of the sample is obtained through the analysis of the central control unit; (2) Mode 2: used to detect the thermal signal of the sample The electrical signal application unit, film 1, and film 3 form a closed thermal circuit; the probe driving unit drives the probe to a certain position on the sample surface, so that the needle tip is in contact with the sample surface, and the electrical signal application unit applies an electrical signal to the needle tip, and the current flows into the The needle tip is heated, and the needle tip and the sample perform heat exchange, so that a voltage signal is generated in the thermal circuit, the thermal signal of the sample is obtained through the thermal signal acquisition unit, and the thermal signal image of the sample is obtained through the analysis of the central control unit. 8. Utilize the detection mode in-situ, synchronous, real-time detection method of the electrical and thermal properties of the micro/nano pyroelectric in-situ detection device based on scanning probe microscope claimed in claim 7, it is characterized in that: comprise the steps: Step 1: The sample is fixed on the scanning probe microscope platform, using the above-mentioned detection mode 1, the probe is displaced to the initial position, and the sample surface is directional scanned along the lateral direction to obtain the topography image and conductive signal image of the sample; Step 2: The probe is moved to the initial position in step 1, and the above-mentioned detection mode 2 is used to scan the surface of the sample along the transverse direction described in step 1 to obtain the thermal signal image of the sample. 9. The micro/nano pyroelectric in-situ detection device based on a scanning probe microscope according to any one of claims 1 to 4, wherein the needle tip includes a needle tip body and a thermal resistance material layer, the first The conductive layer and the second conductive layer; the thermal resistance material layer is located on the surface of the needle point body, and the second conductive layer is located on the surface of the thermal resistance material layer; the first conductive layer communicates with the thermal resistance material layer. 10. The scanning probe microscope-based micro/nano pyroelectric in-situ detection device according to claim 9, characterized in that: the second conductive layer is integrated in the thermal resistance material layer. 11. The micro/nano pyroelectric in-situ detection device based on scanning probe microscope according to claim 9, characterized in that: it includes the following two detection modes: (1) Mode 1: used to detect the surface morphology and conductive signal of the sample The probe driving unit drives the probe to move to an initial position on the sample surface, and the probe conducts a directional scan on the sample surface from the initial position along the transverse direction, and controls the point contact between the probe tip and the sample surface during the scanning process. The first conductive layer, the thermal resistance material layer and the second conductive layer form a closed electrical circuit; the displacement or vibration signal acquisition unit receives the longitudinal displacement signal or vibration signal of the probe tip, and obtains the shape signal of the sample through the analysis of the central control unit; at the same time , the electrical signal applying unit applies an electrical signal to the needle tip, and the electrical signal flows into the first conductive layer, the thermal resistance material layer, the second conductive layer and the sample to form a voltage signal, and the electrical signal acquisition unit obtains the conductive signal of the sample, which is controlled by the center Cell analysis to obtain the conductive signal image of the sample; (2) Mode 2: used to detect the thermal signal of the sample The electrical signal application unit, the first conductive layer and the thermal resistance material layer form a closed loop; the electrical signal application unit heats the thermal resistance material layer, and then heats the probe tip, so that the temperature of the probe tip is different from the temperature of the sample; The probe driving unit drives the probe tip to contact the sample, and heat exchange occurs between the sample and the probe tip, which in turn affects the temperature of the thermal resistance material layer. Due to the thermal resistance effect, the resistance value of the thermal resistance material layer changes. After being collected by the signal acquisition unit, it is analyzed by the central control unit to obtain the thermal signal image of the sample.