CN-122025490-A - Vertical nano air channel photoelectric device with built-in electric field regulating photocathode and preparation method thereof

CN122025490ACN 122025490 ACN122025490 ACN 122025490ACN-122025490-A

Abstract

The application discloses a vertical nanometer air channel photoelectric device with a built-in electric field regulating photocathode and a preparation method thereof, belonging to the technical field of photoelectric devices and high-speed photoelectric conversion, wherein the device comprises a substrate, a lower electrode positioned on the substrate, an insulating isolation layer, a photocathode layer positioned on the lower electrode, an upper electrode positioned above the photocathode layer and a nanometer air channel positioned between the photocathode layer and the upper electrode; the preparation method comprises the steps of forming a lower electrode, forming a photocathode layer and constructing a built-in electric field, forming an insulating isolation layer, forming a spacing/sacrificial structure and preparing an upper electrode, and removing the sacrificial structure to form a nano air channel. The photoelectric device provided by the application is suitable for high-speed photoelectric detection, millimeter wave/terahertz light mixing and coherent reception.

Inventors

LI MO
SUN LIXIN
CHEN FEILIANG
ZHAO HAIQUAN
LIU YANG
JIANG HAO
YANG FAN
ZHANG JIAN

Assignees

电子科技大学

Dates

Publication Date: 20260512
Application Date: 20260212

Claims (10)

1. A vertical nano-air channel optoelectronic device with a built-in electric field-modulated photocathode, comprising a substrate, characterized in that the device further comprises: The electrode comprises an upper electrode and a lower electrode, and the upper electrode and the lower electrode are arranged above the substrate; The photocathode layer is arranged above the lower electrode and below the upper electrode, and a built-in electric field is arranged in the photocathode layer along the thickness direction so as to drive photo-generated carriers to directionally transport to the emission surface in the photocathode layer, so that electrons are emitted into the nano air channel from the emission surface under the assistance of an externally-applied bias and transported to the upper electrode to form photocurrent; The insulating isolation layers are arranged on two sides or the periphery of the photocathode layer so as to support the upper electrode; And the nanometer air channel is arranged between the photocathode layer and the upper electrode.
2. The vertical nano-air channel optoelectronic device of a built-in electric field-modulated photocathode of claim 1, wherein the built-in electric field is realized by graded doping by ion implantation and/or graded doping by in-situ doped growth.
3. The vertical nano-air channel optoelectronic device of a built-in electric field-modulated photocathode of claim 1 wherein the built-in electric field is realized by a band gradient formed by gradual change of material composition along the thickness direction.
4. The vertical nano-air channel optoelectronic device of claim 1 wherein said built-in electric field-modulated photocathode is formed by a heterojunction or space-charge region.
5. The vertical nano-air channel optoelectronic device of a built-in electric field modulated photocathode of claim 1 wherein the nano-air channel thickness is no more than 1000 nm a.
6. A method for manufacturing a vertical nano-air channel optoelectronic device with a built-in electric field-controlled photocathode, the method being used for manufacturing the optoelectronic device according to any one of claims 1 to 5, the method comprising: forming and patterning a lower electrode on a substrate; Forming a photocathode layer on the lower electrode, and preparing a built-in electric field; Preparing an insulating isolation layer as a structure for isolating and supporting the upper electrode and the lower electrode while defining a nano-air channel region; preparing a spacing structure or a sacrificial structure for defining a nano-air channel, and forming an upper electrode above the spacing structure or the sacrificial structure; And removing the sacrificial structure or releasing the spacing structure to form the nano air channel, so that a nano air channel is formed between the photocathode layer and the upper electrode.
7. The method for fabricating a vertical nano-air channel photovoltaic device with built-in electric field controlled photocathode of claim 6, wherein the sacrificial structure comprises an inorganic sacrificial layer and/or an organic sacrificial layer, and the removing means comprises one or more of wet etching, dry etching, thermal decomposition or solvent stripping.
8. The method for fabricating a vertical nano-air channel photovoltaic device with built-in electric field controlled photocathode of claim 6, wherein the insulating isolation layer is a ring-shaped, column-shaped or step-shaped supporting structure, and is formed by deposition and patterning.
9. The method of claim 6, further comprising forming an upper electrode for connecting to a radio frequency extraction structure or an antenna structure by sputtering, evaporation, electroplating or transfer.
10. The method for manufacturing a vertical nano-air channel optoelectronic device with a built-in electric field controlled photocathode of claim 6, wherein the manufacturing the built-in electric field comprises: The doping gradient is formed by ion implantation and annealing activation or in-situ doping growth to obtain a built-in electric field, or the energy band gradient built-in electric field is obtained by gradual change of the components of the epitaxial/deposition regulating material along the thickness direction, or a heterojunction is formed in the photocathode layer to obtain a space charge region built-in electric field.

Description

Vertical nano air channel photoelectric device with built-in electric field regulating photocathode and preparation method thereof Technical Field The application belongs to the technical field of photoelectric devices and high-speed photoelectric conversion, and particularly relates to a vertical nano air channel photoelectric device with a built-in electric field regulating photocathode and a preparation method thereof. Background Nanoelectroair channel optoelectronic devices typically employ a vertical structure of "photocathode-nanoelectroair channel (air/vacuum gap) -upper electrode (anode)". When the device works, incident light generates photo-generated carriers in the photocathode, electrons are emitted from the surface of the cathode to enter a nanoscale gap under the assistance of an externally applied bias, and the electrons are transported to an upper electrode under the action of a gap electric field to form photocurrent. Because the gap medium is air or vacuum, the gap is not provided with solid crystal lattices, related phonon scattering and other mechanisms, the movement of electrons in the nano gap is mainly controlled by the acceleration of an electric field, when the gap thickness is nano-scale, the electron flight distance is short, the collision probability is reduced, and the gap side transportation can be similar to drift or even trajectory transition process, so that the gap side transition time is smaller. Therefore, the device has the potential of realizing high-speed photoelectric response and generating and receiving optical mixing and millimeter wave/terahertz signals. However, in the existing structure, the main voltage drop of the applied voltage is often concentrated in the nano air channel and the area near the surface of the cathode, so that the electric field in the photocathode is insufficient, the process of transporting the photo-generated carriers from the generating position to the emitting surface is easily dominated by diffusion or weak field drift, the in-vivo transportation time can become a bandwidth bottleneck of the device, and the output is sensitive to bias voltage change. Common improvement paths for this problem mainly include electric field enhancement (increasing applied bias, decreasing gap to enhance electric field near the surface), geometric shortening (thinning the photocathode layer to shorten in vivo transport distance), surface engineering (surface treatment, NEA activation, etc. to improve emission conditions). The method has the limitations that the electric field enhancement type is difficult to establish enough driving electric field in the photocathode body, the in-vivo transportation bottleneck is not necessarily eliminated, the geometric shortening type can reduce the light absorption and carrier generation amount and introduce the problem of process consistency, the surface engineering type is mainly used for improving the surface emission link and is sensitive to the process/environment, and the problem of insufficient in-vivo directional transportation is difficult to solve. Disclosure of Invention The application aims to overcome the defects of the prior art, and provides a vertical nano air channel photoelectric device with a built-in electric field for regulating and controlling a photocathode and a preparation method thereof, wherein stable directional transportation driving force can be provided in the photocathode while the advantages of short transition of the nano air channel are maintained, so that the bandwidth limitation of in-vivo transportation time and bias dependence are reduced. The aim of the application is achieved by the following technical scheme: a vertical nano-air channel optoelectronic device incorporating an electric field-modulated photocathode, comprising a substrate, the device further comprising: The electrode comprises an upper electrode and a lower electrode, and the upper electrode and the lower electrode are arranged above the substrate; The photocathode layer is arranged above the lower electrode and below the upper electrode, and a built-in electric field is arranged in the photocathode layer along the thickness direction so as to drive photo-generated carriers to directionally transport to the emission surface in the photocathode layer, so that electrons are emitted into the nano air channel from the emission surface under the assistance of an externally-applied bias and transported to the upper electrode to form photocurrent; The insulating isolation layers are arranged on two sides or the periphery of the photocathode layer so as to support the upper electrode; And the nanometer air channel is arranged between the photocathode layer and the upper electrode. Further, the built-in electric field is realized by gradient doping formed by ion implantation and/or gradient doping formed by in-situ doped growth. Further, the built-in electric field is realized by gradually changing the material composition a