Area-controllable self-power photoelectric detection method by utilizing liquid metal needle tip
1. A structure comprises gallium indium alloy (EGaIn) needle tip, metal film (Au or Ag), and n-type silicon substrate with natural oxide layer of 1-3 nm on surface.
2. The structural arrangement as described in claim 1, wherein: one of the electrode materials is a liquid metal tip EGaIn, which is prepared through a needle.
3. The structural arrangement as described in claim 1, wherein: the other electrode material was an about 60nm Au or Ag film plated by magnetron sputtering on a 1.0 cm x 1.0 cm size n-type silicon substrate.
4. The structural arrangement as described in claim 1, wherein: one section of the electrode lead is connected on the EGaIn needle point, one end of the electrode lead is connected on the metal film substrate, and the current passes through the EGaIn and the Au or Ag to form a closed loop.
5. The structural arrangement as described in claim 1, wherein: the EGaIn needle point position is fixed, and the ascending or descending of the substrate is controlled by a piezoelectric device, so that the formation of junctions with different areas is controlled.
6. The structural arrangement as described in claim 1, wherein: the semiconductor laser with the wavelength of 405nm or 660nm is used for measurement at room temperature, good photoelectric detection can be realized, and response characteristics of the photoelectric detection are obviously different for different wavelengths.
7. The structural arrangement as described in claim 1, wherein: the junctions with different areas can realize self-power photoelectric detection under illumination without external bias voltage.
8. The structural arrangement as described in claim 1, wherein: the current-voltage (I-V) curve measured under the condition of 660nm red light can be regulated and controlled through the micro-nano-scale contact area of the EGaIn needle tip and the substrate, and the I-V curve of the small-area junction can also be regulated and controlled through replacing the light source wavelength (405nm purple light).
Background
With the rapid development of semiconductor technology, various new types of photodetectors have been developed. However, once the structure of the current photoelectric detector is formed, the performance of the current photoelectric detector is difficult to regulate and control, so that different application conditions are met. Moreover, they often require an external power source to ensure proper operation of the device. Liquid metal eutectic gallium indium alloys (EGaIn) are considered to be one of the most promising materials for the fabrication of soft microelectronic devices due to their high thermal and electrical conductivity, good self-healing capability and ductility. Because the oxide causing the maximum reduction of Gibbs free energy dominates the surface of the alloy, the gallium-indium alloy surface oxide is mainly Ga distributed on the outermost layer and has wide band gap (-4.9 eV)2O3 [1]So that it has non-Newtonian characteristics and can be shaped into a conical tip [2 ] having a small radius of curvature]. By utilizing the deformability of the liquid metal and combining with the semiconductor silicon material which is most widely applied at present, the nondestructive self-power photoelectric detector with controllable contact area is hopeful to be formed.
Reference to the literature
[1] Zavabeti, A.;Ou, J. Z.;Carey, B. J.;Syed, N.;Orrell-Trigg, R.;Mayes, E. L. H.;Xu, C.;Kavehei, O.;O’Mullane, A. P.;Kaner, R. B.;Kalantar-zadeh, K.; Daeneke, T., A liquid metal reaction environment for the room-temperature synthesis of atomically thin metal oxides. Science 2017,358(6361), 332-335.
[2] Chen, X.; Hu, H.; Trasobares, J.; Nijhuis, C. A., Rectification Ratio and Tunneling Decay Coefficient Depend on the Contact Geometry Revealed by in Situ Imaging of the Formation of EGaIn Junctions. ACS Appl. Mater. Interfaces 2019,11 (23), 21018-21029。
Disclosure of Invention
The invention aims to solve the technical problem of providing a novel device structure, namely, the self-power performance of the device is regulated and controlled by utilizing an EGaIn needle tip, a metal film (Au or Ag) and an n-type silicon substrate structure and controlling the micro-nano contact area of the EGaIn needle tip and the metal film through piezoelectricity.
The purpose of the invention is realized as follows:
a self-power photoelectric detection method for realizing area control by utilizing a liquid metal needle point is composed of an n-type silicon substrate, an Au or Ag film of about 60nm and an EGaIn needle point, and is characterized in that: the self-adaptive deformation of the liquid metal EGaIn electrode can ensure that the electrode is in contact with the substrate plated with the metal film without damaging the substrate; meanwhile, the size of the prepared tip of the needle point is in a micron level, and the micro-nano contact area of the needle point and the substrate can be well controlled through piezoelectricity, so that the regulation and control of a current-voltage (I-V) curve under the subsequent illumination are guaranteed.
The invention has the advantages that:
the method has simple experimental device and is convenient to realize. By using liquid stateThe metal electrode EGaIn realizes the measurement of the area controllable photoelectric property, and the Ga on the surface of the EGaIn needle point is skillfully utilized2O3The layer is used as an intermediate layer, the silicon substrate is used as a light absorption layer, and the metal layer in the loop is used for rapidly conducting photon-generated carriers of the silicon substrate, so that high performance of the device is realized. Meanwhile, the power-saving device also has the self-power characteristic, namely, the power-saving device can work without applying bias voltage and has the function of saving energy. And a new idea is provided for dynamically adjusting the photoelectric property of the device, and the device is expected to be applied to different photoelectric detection scenes.
Drawings
In order to make the object and technical solution of the present invention clearer, the present invention will be further described in detail with reference to the accompanying drawings:
FIG. 1 is a schematic diagram of a method for realizing area-controllable self-power photoelectric detection by using a liquid metal needle tip.
FIG. 1: 1 is a light source, i.e. 405nm violet or 660nm red light; 2 is an EGaIn tip; 3 is an about 60nm metal layer (Au or Ag); 4 is a silicon substrate, and 5 is a piezoelectric device.
FIG. 2 is the I-V curve under dark and red light when the EGaIn tip contacts a small area of the Ag film coated silicon substrate in the example.
FIG. 3 is an I-V curve under dark and red light when the EGaIn tip of the example is in large area contact with the Ag film coated silicon substrate.
FIG. 4 is a dynamic I-t curve under 2V bias voltage when the EGaIn tip contacts with the junctions of different areas of the silicon substrate plated with Ag film in the example.
FIG. 5 is a dynamic I-t curve under 0V bias voltage when the EGaIn tip contacts with the junctions of different areas of the silicon substrate plated with Ag film in the example.
FIG. 6 is the I-V curve under dark and red or violet light when the EGaIn tip contacts with a small area of the silicon substrate plated with Ag film in the example.
Detailed Description
An area-controllable measurement structure for photoelectric detection, results and schematic diagrams of the principle are provided, please refer to fig. 1-6.
The following describes in detail an embodiment of the present invention with reference to fig. 1.
The implementation method comprises the following steps: firstly, extruding a drop of EGaIn (2) from a needle tube with good air tightness, contacting with a gold-plated silicon substrate subjected to magnetron sputtering, controlling a piezoelectric device (5) to separate so as to form a conical needle point, then fixing the position of the needle point, adopting another piece of gold-plated or silver-plated n-Si as a test sample, controlling the ascending of a substrate through the piezoelectric device (5), regulating and controlling the contact area of the EGaIn needle point and the substrate, and irradiating by using a 660nm red light source (1) to realize the control of an I-V curve. And under the same contact area, a purple light source (1) with 405nm is adopted, so that the difference of I-V response can be obviously seen.
FIG. 2 is an I-V curve of a Ag film plated silicon substrate in the dark and under 660nm red light with small area junction contact, and the structure can be seen to have an optical response.
Fig. 3 is an I-V curve under dark and red light when the substrate is continuously controlled to move upwards by the piezoelectric device under the condition of fig. 2 to form a large-area micro junction, and it can be seen that the shape of the I-V curve is obviously changed at this time, which indicates that the optical response characteristic of the device can be adjusted by controlling the contact area.
Fig. 4 and 5 are dynamic current-time (I-t) curves at 2V bias and 0V bias, respectively, when an EGaIn tip is in contact with different area junctions of a silicon substrate plated with an Ag film. It can be seen that the device has self-power behavior, exhibits stable and good red light response, and has response time less than 50 ms.
Fig. 6 shows the I-V response of the device structure under the condition of fig. 2 under different wavelengths of light, i.e. under the illumination of purple light 405nm or red light 660nm, and it can be seen that the device has different light response behaviors for different wavelengths of light.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
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