CN112834786B - Three-dimensional manipulation of nanoparticles based on scanning probes - Google Patents

Abstract

The invention discloses a nanoparticle three-dimensional manipulation device and method based on a scanning probe. The device includes a scanning probe that is conductive and coated with a low surface energy coating, as well as a scanning module and an observation module. The observation module is used to observe the position of the scanning probe and the nanoparticle; the scanning module moves the scanning probe to the vicinity of the nanoparticle according to the position image collected by the observation module, and regulates the probe and the nanoparticle by applying a voltage signal on the surface of the probe The interaction between them can finally realize the pick-up, transfer and placement of single nanoparticles in three-dimensional space. In the invention, the voltage signal of the scanning probe is regulated, and the dielectrophoretic force is introduced to realize the regulation of the surface energy thereof, so that the nano-particle can be controlled efficiently and repeatedly.

Description

Three-dimensional manipulation of nanoparticles based on scanning probes

technical field

The invention relates to the technical field of nanoscale devices, in particular to a three-dimensional manipulation method of nanoparticles based on a scanning probe.

Background technique

With the development of quantum and nano-optics, the research of nano-device and structural integration has attracted a lot of attention. The manipulation of nano-objects using scanning probes has proven to be a promising method that can be applied in many fields. It plays an important role in a wide range of fields such as biochemical research and nanostructure preparation.

Some existing methods for manipulating nanoparticles use scanning probes to "push" and "pull" the nanoparticles to move two-dimensionally on a flat surface. Due to the limitation of 2D mobility, these methods cannot realize the transfer of nanoparticles on planes with different heights or on different platforms, thus limiting their application in practical nanodevice fabrication. In order to solve this problem, it is necessary to use scanning probes to realize nano-manipulation in the vertical direction, that is, to achieve three-dimensional manipulation of nanoparticles by means of "pick-up" and "place".

At present, some studies have proposed a method of using near-field optical force to capture particles in a liquid environment, but since this method can only be limited in a liquid environment, it cannot be applied to the preparation of nanodevices. The reason is that in the process of "pickup" and "placement", the force between the probe and the particle is required to be larger and smaller than the force between the sample and the particle, respectively, resulting in no effective method to achieve the atmospheric environment. Method for controllable and repeatable pick-and-place of nanoparticles at solid-air interfaces.

SUMMARY OF THE INVENTION

In view of the above problems, the present invention provides a three-dimensional manipulation method of nanoparticles based on a scanning probe, which can effectively and controllably realize the repeatable transfer and manipulation of single nanoparticles in three-dimensional space in an atmospheric environment.

The technical scheme adopted by the device of the present invention is as follows:

A three-dimensional manipulation device for nanoparticles based on a scanning probe, comprising a scanning probe, a scanning module and an observation module, the scanning probe is conductive and coated with a low surface energy coating; the observation module is used for real-time observation of the scanning probe and The position of the nanoparticle; the scanning module is used to control the displacement and scanning of the scanning probe in the three-dimensional space according to the position image collected by the observation module, and regulate the voltage signal on the surface of the scanning probe.

Further, the nanoparticles are placed on a substrate, and the surface of the substrate is coated with a conductive layer.

Further, the observation module is an imaging system of an optical microscope or an imaging system of an electron microscope.

The present invention uses the above-mentioned device to control the method, and the specific steps include: using the observation module to observe the position of the scanning probe and the nanoparticle; the scanning module moves the scanning probe to the vicinity of the nanoparticle according to the position image collected by the observation module, and then the A voltage is applied to the surface of the scanning probe, so that the interaction energy between the probe and the particle is greater than the interaction energy between the particle and the substrate, so as to pick up the nanoparticle; then the scanning probe is controlled to move to a designated position by applying a modulated voltage. The voltage intensity applied on the surface of the scanning probe is reduced, so that the interaction energy between the probe and the particle is smaller than the interaction energy between the particle and the substrate, and finally the nanoparticles are desorbed from the surface of the probe and placed at the designated position.

The present invention regulates the voltage signal of the scanning probe, and then introduces dielectrophoretic force to realize the regulation of its surface energy, which can efficiently and controllably realize the manipulation of nanoparticles, and has the following beneficial effects:

(1) The present invention uses a scanning probe to directly manipulate nanoparticles, and can simply, effectively and repeatably realize the picking, transferring and placing of single nanoparticles in three-dimensional space under the positioning of nanometer precision.

(2) The present invention does not require a special use environment, and can be directly applied in the atmospheric environment.

(3) The present invention does not require the material of the nanoparticles to be manipulated, and can be applied to nanoparticles of various materials.

Description of drawings

FIG. 1 is a schematic structural diagram of a nanoparticle three-dimensional manipulation device based on a scanning probe according to the present invention. Among them, 1-observation module, 2-sample substrate, 3-nanoparticles, 4-scanning probe, 5-scanning module.

FIG. 2 is a schematic structural diagram of the optical microscope imaging system in the observation module. Among them, 6-light source, 7-objective lens, 8-transflective mirror, 9-color filter, 10-optical camera.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the following specific embodiments are only used to illustrate the present invention and not to limit the scope of the present invention.

Referring to FIG. 1 , a scanning probe-based three-dimensional manipulation device for nanoparticles in this embodiment includes a scanning probe 4 , a sample substrate 2 , nanoparticles 3 , a scanning module 5 , and an observation module 1 .

The observation module 1 may be an imaging system of an optical microscope or an imaging system of an electron microscope. As shown in FIG. 2 , the imaging system of an optical microscope includes a light source 6 , an objective lens 7 , a half mirror 8 , a color filter 9 and an optical camera 10 . The light emitted by the light source 6 is focused on the sample after passing through the half mirror 8 and the objective lens 7 , and the optical signal emitted by the sample is collected by the objective lens 7 , and then imaged on the optical camera 10 after passing through the color filter 9 . The light source 6 includes a white light source and a laser light source of various wavelengths. After being irradiated by the light source 6, the light emitted by the nanoparticles 3 includes reflected light, scattered light and fluorescence. The optical signal needs to be imaged on the optical camera 10 , and then the position of the nanoparticles can be located by the image of the optical camera 10 .

The sample substrate 2 is a transparent substrate, and a conductive layer is plated on the surface of the substrate to increase the electric field locality on the surface of the tip of the probe when a voltage signal is applied. Nanoparticles 3 can be nanoscale particles of various materials, and a monodispersed nanoparticle sample with uniform particle size distribution can be prepared by solution spin coating.

其中

和E_die分别为探针与颗粒之间的范德华力和介电泳力的作用能。在探针扫描过程中，虽然探针在各个位置停留时间短(小于0.1s)，但是由于探针的高频率振动(＞140kHz)，探针与颗粒多次接触(大于10000次)，因此颗粒与探针或衬底吸附的概率服从玻尔兹曼分布函数，P～exp(-U/kbT)，其中U＝-E_tip，U＝-E_sub分别对应探针与样品衬底的表面能。通过调节扫描探针4上的电压信号，引入介电泳力的作用，进而改变探针与颗粒之间作用能的大小E_tip＞E_sub，使颗粒从衬底表面吸附到探针针尖。The scanning probe 4 is a conductive probe coated with fluorocarbon on the surface by a method of plasma deposition, and the displacement of the probe is controlled by the scanning module 5 with nanometer precision. When the tip of the scanning probe 4 is lowered to the surface of the sample substrate 2, select an appropriate light source and illumination angle to determine the position of the probe tip in the field of view of the optical camera, and then combine with the previously determined position of the nanoparticles 3, in Under the control of the scanning module 5, the scanning probe 4 is moved to the vicinity of the nanoparticle 3 (less than 10 μm), and then a small-scale scanning is performed. First, a voltage (-10V) was applied to the probe surface. At this time, due to the "lightning rod effect", the electric field intensity near the probe tip is extremely strong, so the nanoparticles 3 are affected by the dielectrophoretic force of the probe tip, and the surface binding energy of the nanoparticles 3 and the probe tip is

in

and E _die are the interaction energy of van der Waals force and dielectrophoretic force between probe and particle, respectively. During the probe scanning process, although the probe stays at each position for a short time (less than 0.1s), due to the high frequency vibration of the probe (>140kHz), the probe contacts the particles for many times (more than 10,000 times), so the particles The probability of adsorption to the probe or substrate obeys the Boltzmann distribution function, P～exp(-U/kbT), where U=-E _tip and U=-E _sub correspond to the surface energy of the probe and the sample substrate, respectively . By adjusting the voltage signal on the scanning probe 4, the effect of dielectrophoretic force is introduced, thereby changing the magnitude of the interaction energy between the probe and the particle E _tip >E _sub , so that the particles are adsorbed from the substrate surface to the probe tip.

After the nanoparticle 3 is successfully adsorbed by the scanning probe 4, combined with the positioning of the observation module 1, the scanning module 5 is used to control the displacement of the probe to move the nanoparticle 3 to a designated position. Finally, adjust the voltage signal on the probe surface (triangular pulse voltage, ±10V, 100Hz), and then adjust the interaction energy between the probe and the nanoparticle E _tip <E _sub , so that the particle is desorbed from the probe surface and placed in the specified position position.

Claims (2)

1. A nanoparticle three-dimensional control method based on a scanning probe is characterized in that the device adopted by the method comprises the scanning probe, a scanning module and an observation module, wherein the scanning probe is a conductive probe with a fluorocarbon plated surface, and the method specifically comprises the following steps: observing the positions of the scanning probe and the nano particles by using an observation module, wherein the nano particles are positioned in an atmospheric environment, the nano particles are placed on a substrate, and a conductive layer is plated on the surface of the substrate; the scanning module moves the scanning probe to the position near the nano-particles according to the position image collected by the observation module, then-10V voltage is applied to the surface of the scanning probe for scanning, at the moment, the electric field intensity near the probe tip is extremely strong, so that the nano-particles are under the action of dielectrophoresis force of the probe tip, the action energy between the probe and the particles is larger than that between the particles and the substrate, the nano-particles are picked up, the stay time of the probe at each position is less than 0.1s, the vibration frequency of the probe is more than 140kHz, and the contact frequency of the probe and the nano-particles is more than 10000 times in the scanning process of the probe; and then the scanning module controls the scanning probe to move to a specified position, triangular pulse voltage with the frequency of 100Hz and the voltage of +/-10V is applied to the surface of the scanning probe, and the action energy between the probe and the particles is smaller than that between the particles and the substrate by reducing the intensity of the voltage applied to the surface of the scanning probe, so that the nanoparticles are desorbed from the surface of the probe and placed at the specified position.

2. The scanning probe-based nanoparticle three-dimensional manipulation method according to claim 1, wherein the observation module is an imaging system of an optical microscope or an imaging system of an electron microscope.

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