CN102723350B - PbSe colloidal quantum dot based array Hall element and preparation method thereof - Google Patents

Abstract

The invention relates to a novel structure array Hall element based on PbSe colloidal quantum dots and a manufacturing method thereof. It has the advantages of small structure, arbitrary bending and high sensitivity. The PbSe colloidal quantum dot sensitive unit is a plurality of connected in series and arranged on a flexible substrate in a dot array. One end of the unit is a current input terminal electrode, and the other end is a current output terminal electrode. Each PbSe colloidal quantum dot The signals of the sensitive units are respectively output through their respective signal output electrodes I, and the signal output electrodes I and II of all PbSe colloidal quantum dot sensitive units are arranged together and connected to their respective signal output ports. The manufacturing method of the unit includes: First, a single PbSe colloidal quantum dot sensitive unit 8 is prepared, and then the electrodes are evaporated, first the signal output electrode I and the signal output electrode II are evaporated, a protective layer is plated on them, and finally the current input terminal electrode and the current output terminal electrode are evaporated.

Description

Fabrication method of array Hall element based on PbSe colloidal quantum dots

technical field

The invention relates to a novel structure array Hall element based on PbSe colloidal quantum dots and a manufacturing method thereof. This Hall element uses PbSe colloidal quantum dot material, arranged in an array, and has the characteristics of good flexibility. It has the advantages of small structure, arbitrary bending and high sensitivity. the

Background technique

The Hall element is a magnetic sensitive element that performs magnetoelectric conversion according to the Hall effect. It has the advantages of sensitivity to magnetic field, simple structure, small size, wide frequency response, large output voltage change and long service life, so it is widely used in electromagnetic measurement, non-electrical measurement, automatic control, computing and communication devices and other fields. the

At present, the material of the Hall element is mostly semiconductor materials such as germanium, silicon, gallium arsenide, indium arsenide, and indium antimonide. The size of the element is relatively large, and the characteristic parameters of these semiconductor materials such as carrier concentration and mobility change with temperature. Large, causing the Hall resistivity to vary greatly with temperature, and the operating temperature of the Hall element is limited. PbSe has narrow band gap, high quantum efficiency, low noise, and is sensitive to the influence of external conditions. Using colloidal quantum dot materials, micro-nano-sized Hall elements can be produced, with high sensitivity and flexibility, which makes it more convenient to measure the magnetic field in any direction in space. the

At present, many Hall elements use a single Hall element to work independently or assemble multiple Hall elements together, which has certain limitations for the measurement of the magnetic field. The Hall element array is integrated on the same substrate, which has high reliability, consistency and sensitivity. the

After searching, it is found that there is no report of an array Hall element using PbSe colloidal quantum dots as a sensitive material and integrated on a flexible substrate in my country. the

Contents of the invention

In view of the above problems, the present invention proposes an array Hall element based on PbSe colloidal quantum dots and a manufacturing method thereof. This Hall element array is fully integrated on a flexible substrate, and PbSe colloidal quantum dots are used as the sensitive material, which greatly simplifies the manufacturing process and reduces the size of the Hall element. the

Above-mentioned purpose of the present invention is realized by following technical scheme, is described as follows in conjunction with accompanying drawing:

An arrayed Hall element based on PbSe colloidal quantum dots, comprising a PbSe colloidal quantum dot sensitive unit, a current input terminal electrode, a current output terminal electrode, a signal output electrode I and a signal output electrode II, the PbSe colloidal quantum dot sensitive unit 8 is a plurality of connected in series and arranged on the flexible substrate 1 in a dot array. One end of the PbSe colloidal quantum dot sensitive unit 8 is the current input terminal electrode 2, and the other end is the current output terminal electrode 7. Each PbSe colloidal quantum dot The signal of the point sensitive unit 8 is output through the signal output electrode I3 and the signal output electrode II6 respectively, and the signal output electrodes I3 of all PbSe colloidal quantum dot sensitive units 8 are arranged together and connected to the signal output terminal interface I4, The signal output electrodes II6 of all PbSe colloidal quantum dot sensitive units 8 are collectively arranged and connected to the signal output port II5. the

As above-mentioned a kind of manufacturing method based on the array type Hall element of PbSe colloidal quantum dot, the manufacturing method of each PbSe colloidal quantum dot sensitive unit 8 is exactly the same, and concrete steps are as follows:

1) Put 0.892g of PbO, 2.26g of oleic acid and 12.848g of octadecene into a three-necked flask, heat it to 170°C in a nitrogen atmosphere, and quickly inject 6.4g of Se/tributyl with a mass ratio of 10%. Phosphine solution, the temperature of the reaction solution dropped rapidly to 148°C, after 3 minutes of growth, the reaction was extinguished with toluene solution, and purified to obtain PbSe quantum dots;

2) Prepare the PbSe quantum dots into a chloroform solution with a concentration of 15 mg/mL, take 5 mL of the quantum dot solution and 3 mL of tert-butyl N-(2-mercaptoethyl) carbamate into a centrifuge tube, shake the centrifuge tube for more than 2 hours, wash with methanol The quantum dots are washed twice, and finally dissolved in chloroform, so that the ligands on the surface of the quantum dots have photoreactivity, and the colloidal quantum dots are non-polar systems at this time;

3) Dissolve 30 mg of the above-mentioned surface-modified quantum dots and 1.5 mg of di-tert-butylphenyliodonium perfluorobutane-sulfonate into 1 mL of chloroform, and spin-coat the mixed solution on the cleaned flexible substrate 1 using a homogenizer to form PbSe The colloidal quantum dot layer 9 is covered on the PbSe colloidal quantum dot layer 9 through a pre-made mask template 11. The mask template 11 just exposes the position of the single PbSe colloidal quantum dot sensitive unit 8 to the outside, and passes through a 10-minute ultraviolet lamp. Irradiate the mask template 11, so that the ligands on the surface of the single PbSe colloidal quantum dot sensitive unit 8 are bonded to form a polar system, and then anneal for 2 minutes on a baking tray at 100 ° C, and use n-hexane to clean the substrate. The exposed non-polar quantum dot system is washed away, so that a single PbSe colloidal quantum dot sensitive unit 8 is prepared;

4) Evaporation electrodes, since the current input terminal electrode 2, the current output terminal electrode 7, the signal output electrode I 3, and the signal output electrode II6 intersect in space, first the signal output electrode I 3 and the signal output electrode II6 are evaporated, and evaporated When plating electrodes, first make a mask plate according to the design size. After covering the mask plate, use thermal evaporation technology to evaporate the signal output electrode I3 and signal output electrode II6. After the electrodes are evaporated, remove the mask plate. In this way, the vapor deposition of signal output electrode I3 and signal output electrode II6 has been completed;

5) Plating protective layer 10, the left and right ends of a single PbSe colloidal quantum dot sensitive unit 8 are connected to the current input terminal electrode 2 and the current output terminal electrode 7 without coating, and the method for evaporating the protective layer 10 is similar to the method for plating electrodes , that is to make a suitable mask, and remove the mask after evaporating the _SiO2 protective layer by electron beam;

6) Evaporating the current input terminal electrode 2 and the current output terminal electrode 7, the method of plating the current input terminal electrode 2 and the current output terminal electrode 7 is the same as the method of evaporating the signal output electrode I 3 and the signal output electrode II6, so that it is completed Fabrication of arrayed Hall elements based on PbSe colloidal quantum dots. the

The technical effect of the invention is: the size of the Hall element is small, the manufacture is simple and flexible, and the measurement of the spatial magnetic field has obvious advantages compared with the existing Hall element. the

Description of drawings

Figure 1 shows the overall structure of the arrayed Hall element based on PbSe colloidal quantum dots. the

Fig. 2 Electrical schematic diagram of arrayed Hall element based on PbSe colloidal quantum dots. the

Figure 3 is a three-dimensional structure diagram of a single PbSe colloidal quantum dot sensitive unit. the

Figure 4 PbSe colloidal quantum dot sensitive unit shape structure diagram. the

Figure 5 is a schematic diagram of coating PbSe colloidal quantum dot layer. the

Figure 6(a) Overlay chrome/quartz template schematic diagram. the

Fig. 6(b) is a top view of Fig. 6(a). the

Figure 7 is a three-dimensional schematic diagram covering the chrome/quartz template. the

Figure 8(a) Schematic diagram of etching a single PbSe colloidal quantum dot sensitive unit. the

Fig. 8(b) is a top view of Fig. 8(a). the

Fig. 9(a) schematic diagram of plating signal output wire. the

Fig. 9(b) is a top view of Fig. 9(a). the

Figure 10 Schematic diagram of plating protective layer. the

Figure 11(a) Plating current input and current output electrodes. the

Fig. 11(b) is a top view of Fig. 11(a). the

In the figure: 1-flexible substrate 2-current input electrode 3-signal output electrode I 4-signal output interface I 5-signal output interface II 6-signal output electrode I 7-current output electrode 8-PbSe colloid Quantum dot sensitive unit 9-PbSe colloidal quantum dot layer 10-protective layer 11-chrome/quartz template

Detailed ways

The following are only preferred embodiments of the present invention, and should not limit the scope of the present invention. That is, all equivalent changes and modifications made according to the patent scope of the present application shall still fall within the scope covered by the present patent. The structure and manufacturing method of the present invention are specifically described below with examples. the

The present invention has taken the overall structural scheme shown in Fig. 1. Taking the 4×4 dot matrix as an example, 2 is the electrode of the current input terminal, and 7 is the electrode of the current output terminal. Since the input voltage of each PbSe colloidal quantum dot sensitive unit 8 is the same, in order to simplify the circuit, each PbSe colloidal quantum dot sensitive unit 8 is connected in series. Similarly, for the 4×4 dot matrix, since the Hall voltage value of each PbSe colloidal quantum dot sensitive unit 8 will be read in turn, the signal of each PbSe colloidal quantum dot sensitive unit 8 is passed through the signal output electrode I3 respectively. And signal output electrode II6 output. In order to prevent the occurrence of short circuit, the current input terminal electrode 2 and the current output terminal electrode 7 and the signal output electrode I 3 and the signal output electrode II 6 are connected by means of isolation. The signal output electrodes I3 of all PbSe colloidal quantum dot sensitive units 8 are arranged together and connected to the signal output port interface I4. The signal output electrodes II6 of all PbSe colloidal quantum dot sensitive units 8 are arranged together and connected to the signal output port interface II5. Because the flexible substrate 1 adopted by the whole Hall element, and the PbSe colloidal quantum dot sensitive unit 8, the current input terminal electrode 2, the current output terminal electrode 7, the signal output electrode I 3, and the signal output electrode II6 thickness are all very small, which makes The whole Hall element can be bent arbitrarily, which is convenient for space magnetic field measurement. The electrical schematic diagram of the overall structure described in Fig. 1 is shown in Fig. 2, in the case that there is a magnetic field and a current is input from the current input terminal electrode 2 and the current output terminal electrode 7 is output, it can pass through the signal output terminal interface I 4 And the signal output terminal interface II5 reads the Hall voltage on the corresponding PbSe colloidal quantum dot sensitive unit 8, thus completing the detection of the spatial magnetic field. the

According to FIG. 3 , it shows the three-dimensional structure of a single PbSe colloidal quantum dot sensitive unit 8 , and FIG. 4 shows the plane shape of a single PbSe colloidal quantum dot sensitive unit 8 . A PbSe colloidal quantum dot sensitive unit 8 is spin-coated on the flexible substrate 1 . A current input terminal electrode 2 and a current output terminal electrode 7 are evaporated on the left and right ends of the PbSe colloidal quantum dot sensitive unit 8 . On the upper and lower ends of the PbSe colloidal quantum dot sensitive unit 8, a signal output electrode I3 and a signal output electrode II6 are evaporated. When working, the working current is input through the electrode 2 of the current input terminal, then passes through the PbSe colloidal quantum dot sensitive unit 8, and then is output through the electrode 7 of the current output terminal. When there is a magnetic field, there is an obvious Hall phenomenon in the PbSe colloidal quantum dot sensitive unit 8, and the measurement of the magnetic field can be realized indirectly by reading the voltage signals on the signal output electrode I3 and the signal output electrode II6. In this way, a plurality of such PbSe colloidal quantum dot sensitive units 8 are integrated as required on the same flexible substrate 1, and these PbSe colloidal quantum dot sensitive units 8 are respectively connected according to certain electrical rules to form a PbSe colloidal quantum dot based Arrayed Hall elements. the

By changing the number of integrated PbSe colloidal quantum dot sensitive units 8 on the flexible substrate, Hall elements of different specifications can also be manufactured. For example, there will be 8×8, 16×16, 8×16 and so on. Simply modifying the number of PbSe colloidal quantum dot sensitive units 8 or adjusting the shape parameters of the PbSe colloidal quantum dot sensitive units 8 is the content of the invention. the

In order to illustrate this new structure PbSe colloidal quantum dot array Hall element more clearly, the present invention takes one of the sensitive units for illustration, and the manufacturing method of other units is exactly the same as the manufacturing method of this unit, and is synchronized during manufacture. Figures 5 to 11 are schematic diagrams of the entire production process

Put 0.892g PbO, 2.26g oleic acid and 12.848g octadecene into a three-necked flask, heat it to 170°C in a nitrogen atmosphere, and quickly inject 6.4g Se/tributylphosphine solution (mass ratio is 10% ), the temperature of the reaction solution dropped rapidly to 148° C., and after 3 minutes of growth, the reaction was quenched with toluene solution, and purified to obtain PbSe quantum dots. Configure the PbSe quantum dots into a chloroform solution with a concentration of 15mg/mL, take 5mL of the quantum dot solution and 3mL of tert-butyl N-(2-mercaptoethyl)carbamate into a centrifuge tube, and shake the centrifuge tube for more than 2 hours. Quantum dots were washed twice with methanol and finally dissolved in chloroform. In this way, the ligands on the surface of the quantum dots have photoreactivity, and the colloidal quantum dots are non-polar systems at this time. the

Referring to Fig. 5, 30 mg of the above-mentioned surface-modified quantum dots and 1.5 mg of di-tert-butylphenyliodonium perfluorobutane-sulfonate were dissolved in 1 mL of chloroform, and the mixed solution was spin-coated on the cleaned flexible substrate 1 using a coater to form PbSe colloidal quantum dot layer 9 . Referring to Fig. 6 and Fig. 7, cover on the PbSe colloidal quantum dot layer 9 by the pre-made mask template 11, the mask template 11 just exposes the position of the single PbSe colloidal quantum dot sensitive unit 8 outside, by 10 minutes The mask template 11 is irradiated by an ultraviolet lamp, so that the ligands on the surface of the single PbSe colloidal quantum dot sensitive unit 8 are bonded off to form a polar system, and then annealed on a baking tray at 100° C. for 2 minutes. The substrate was cleaned with n-hexane to wash off the unexposed non-polar quantum dot system, thus a single PbSe colloidal quantum dot sensitive unit 8 was prepared, and the result is shown in FIG. 8 . the

After completing the preparation of a single PbSe colloidal quantum dot sensitive unit 8, it will be an evaporation electrode. Because the current input terminal electrode 2, the current output terminal electrode 7, the signal output electrode I 3, and the signal output electrode II6 have intersections in space, they cannot be simultaneously These electrodes are evaporated. Referring to FIG. 9, first, the signal output electrode I3 and the signal output electrode II6 are evaporated. When evaporating electrodes, first make a mask plate according to the designed size. After covering the mask plate, use thermal evaporation technology to evaporate the signal output electrode I 3 and signal output electrode II6. After evaporating the electrodes, remove the mask plate , thus completing the evaporation of the signal output electrode I3 and the signal output electrode II6. After the above steps are completed, referring to FIG. 10 , a protective layer 10 is plated. The effect of protective layer 10 has two points, one is to protect single PbSe colloidal quantum dot sensitive unit 8, prevent it from being oxidized in the air or be subjected to external damage; When the output electrode I 3 and the signal output electrode II6 intersect, they conduct electricity and play an insulating role. When the protective layer 10 is plated, the left and right ends of the single PbSe colloidal quantum dot sensitive unit 8 are connected to the current input terminal electrode 2 and the current output terminal electrode 7 without coating. The method of evaporating the protective layer 10 is similar to that of electrode plating, and a suitable mask is also made, and the mask is removed after the SiO ₂ protective layer is evaporated by an electron beam. After the protective layer 10 is plated, referring to FIG. 11 , the current input terminal electrode 2 and the current output terminal electrode 7 are plated. The method of evaporating the current input terminal electrode 2 and the current output terminal electrode 7 is the same as the method of evaporating the signal output electrode I3 and the signal output electrode II6. In this way, the fabrication of the arrayed Hall element based on PbSe colloidal quantum dots is completed.

Claims (1)

1. A method of making an arrayed Hall element based on PbSe colloidal quantum dots, comprising a PbSe colloidal quantum dot sensitive unit, a current input terminal electrode, a current output terminal electrode, a signal output electrode I and a signal output electrode II, each PbSe The manufacturing method of the colloidal quantum dot sensitive unit (8) is exactly the same, and the specific steps are as follows: 1) Put 0.892g of PbO, 2.26g of oleic acid and 12.848g of octadecene into a three-necked flask, heat it to 170°C in a nitrogen atmosphere, and quickly inject 6.4g of Se/tributyl with a mass ratio of 10%. Phosphine solution, the temperature of the reaction solution dropped rapidly to 148°C, after 3 minutes of growth, the reaction was extinguished with toluene solution, and purified to obtain PbSe quantum dots; 2) Prepare the PbSe quantum dots into a chloroform solution with a concentration of 15 mg/mL, take 5 mL of the quantum dot solution and 3 mL of tert-butyl N-(2-mercaptoethyl) carbamate into a centrifuge tube, shake the centrifuge tube for more than 2 hours, wash with methanol The quantum dots are washed twice, and finally dissolved in chloroform, so that the ligands on the surface of the quantum dots have photoreactivity, and the colloidal quantum dots are non-polar systems at this time; 3) Dissolve 30 mg of the above-mentioned surface-modified quantum dots and 1.5 mg of di-tert-butylphenyliodonium perfluorobutane-sulfonate into 1 mL of chloroform, and spin-coat the mixed solution on the cleaned flexible substrate (1) using a homogenizer to form The PbSe colloidal quantum dot layer (9) is covered on the PbSe colloidal quantum dot layer (9) by a pre-made mask template (11), and the mask template (11) just covers a single PbSe colloidal quantum dot sensitive unit (8) The position is exposed to the outside, and the mask template (11) is irradiated by a UV lamp for 10 minutes, so that the surface ligand of the single PbSe colloidal quantum dot sensitive unit (8) is broken, forming a polar system, and then placed on a baking tray at 100 ° C. On, anneal for 2 minutes, use n-hexane to wash the substrate, and wash off the unexposed non-polar quantum dot system, thus preparing a single PbSe colloidal quantum dot sensitive unit (8); 4) Evaporation electrodes, since the current input electrode (2), the current output electrode (7), the signal output electrode I (3), and the signal output electrode II (6) have intersections in space, first evaporate the signal output electrode Ⅰ(3) and signal output electrode Ⅱ(6). When evaporating electrodes, first make a mask plate according to the designed size. After covering the mask plate, use thermal evaporation technology to perform signal output electrode Ⅰ(3) and signal output. Evaporation of the electrode II (6), remove the mask plate after the electrode is evaporated, thus completing the evaporation of the signal output electrode I (3) and the signal output electrode II (6); 5) Plating protective layer (10), the left and right ends of a single PbSe colloidal quantum dot sensitive unit (8) are connected to the current input terminal electrode (2) and the current output terminal electrode (7) without coating, and the protective layer ( The method of 10) is similar to the method for plating electrodes, namely making a suitable mask plate, adopting electron beam evaporation _SiO2 protective layer and removing the mask plate; 6) Evaporating the current input terminal electrode (2) and the current output terminal electrode (7), the method of evaporating the current input terminal electrode (2) and the current output terminal electrode (7), and the evaporation signal output electrode I (3) and The method of the signal output electrode II (6) is the same, thus completing the fabrication of the arrayed Hall element based on PbSe colloidal quantum dots.