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CN-121985605-A - Carbon-based van der Waals heterojunction photoelectric synaptic device and preparation method thereof

CN121985605ACN 121985605 ACN121985605 ACN 121985605ACN-121985605-A

Abstract

A carbon-based van der Waals heterojunction photoelectric synaptic device comprises a light absorption basal layer, an interface functional layer, a charge transmission layer and an electrode structure, wherein the light absorption basal layer is used for absorbing photons in a solar blind ultraviolet band and generating photo-generated current carriers, the interface functional layer is used for capturing the photo-generated current carriers from the light absorption basal layer through interface defect energy levels and regulating and controlling the conductivity of the charge transmission layer through an electrostatic field, and the electrode structure and the charge transmission layer form ohmic contact. The preparation method comprises the steps of selecting diamond as a light absorption substrate, constructing a van der Waals heterojunction precursor structure of hBN, graphene and hBN on the diamond substrate, utilizing high voltage to promote the generation of irreversible phase change to induce the graphene to open an electronic energy band gap, and constructing electrode structures at two ends of a band gap graphene channel. The invention has the sensing and memory functions of solar blind ultraviolet signals, can realize learning and forgetting processes under the light signals with different illumination intensities, durations and pulse numbers, and can be applied to solar blind ultraviolet detection.

Inventors

  • GUO SILIN
  • HUANG CHENG
  • ZHEN JIAPENG

Assignees

  • 中国人民解放军国防科技大学

Dates

Publication Date
20260505
Application Date
20260409

Claims (10)

  1. 1. A carbon-based van der Waals heterojunction photoelectric synaptic device is characterized by comprising a light absorption basal layer (1), an interface functional layer (2), a charge transmission layer (3) and an electrode structure (4); the light absorption basal layer (1) is monocrystalline or polycrystalline diamond and is used for absorbing photons of the solar blind ultraviolet band and generating photo-generated current carriers; The interface functional layer (2) is positioned between the light absorbing substrate layer (1) and the charge transmission layer (3) and is used for capturing photogenerated carriers from the light absorbing substrate layer (1) through interface defect energy levels and regulating and controlling the conductivity of the charge transmission layer (3) through an electrostatic field; the electrode structure (4) comprises a contact electrode forming an ohmic contact with the charge transport layer (3).
  2. 2. The carbon-based van der waals heterojunction electro-synaptic device as claimed in claim 1, wherein the optical band gap of the light absorbing substrate layer (1) is greater than 5.0eV and the corresponding cut-off wavelength is less than 240nm.
  3. 3. The carbon-based van der waals heterojunction electro-optical synaptic device as claimed in claim 1, wherein the interface functional layer (2) comprises an hBN layer, and a deep level charge trap exists at the interface of the hBN layer and the light absorbing substrate layer (1) for realizing nonvolatile storage of information.
  4. 4. A carbon-based van der Waals heterojunction photovoltaic synaptic device as claimed in any one of claims 1 to 3, wherein the charge transport layer (3) is band gap graphene.
  5. 5. The carbon-based van der Waals heterojunction photovoltaic synaptic device according to claim 4, wherein the band gap of the charge transport layer (3) is 1.0 to 3.0 eV.
  6. 6. A carbon-based van der Waals heterojunction photovoltaic synaptic device as claimed in any one of claims 1 to 3, wherein the electrode structure (4) comprises a source and a drain, the device operating as a photovoltaic memristor.
  7. 7. A carbon-based Van der Waals heterojunction photovoltaic synaptic device as claimed in any one of claims 1 to 3, wherein said electrode structure (4) comprises a source, a drain and at least one gate configured to modulate the Fermi level of said charge transport layer (3) or to control the trapping and releasing of interfacial charges by means of an electrostatic field, the device operating as a phototransistor.
  8. 8. A method for preparing a carbon-based van der Waals heterojunction photoelectric synaptic device as claimed in any one of claims 1 to 7, wherein diamond is selected as a light absorption substrate and a support substrate, a van der Waals heterojunction precursor structure of hBN, few-layer graphene and hBN is constructed on the diamond substrate by a dry transfer technology, static pressure is utilized to promote the generation of irreversible phase change of the hBN to induce graphene to open an electron energy band gap, and finally an electrode structure (4) is constructed at two ends of a band gap graphene channel.
  9. 9. The method for preparing the carbon-based van der Waals heterojunction photoelectric synaptic device according to claim 8, comprising the following specific steps: S1, sequentially placing a diamond substrate in acetone, isopropanol and deionized water for ultrasonic cleaning; S2, stacking hBN, graphene and hBN on the surface of the diamond in an ultra-clean environment to form a van der Waals heterojunction precursor structure; s3, loading the prepared precursor sample into an assembly part of a large cavity press, vacuumizing a cavity, and raising the temperature to 110-200 ℃ for at least 1 hour; s4, under the high-temperature state, loading static pressure to 10-30 Gpa, and maintaining for not less than 1 hour; S5, cooling to room temperature, and then releasing pressure to normal pressure; And S6, taking out a sample, and preparing electrode structures (4) at two ends of the band gap graphene channel to complete device preparation.
  10. 10. The method of manufacturing a carbon-based van der Waals heterojunction photovoltaic synaptic device as claimed in claim 9, wherein in the step S1, diamond is single crystal diamond, in the step S3, the temperature is 140 ℃, and in the step S4, the static pressure is 15 Gpa.

Description

Carbon-based van der Waals heterojunction photoelectric synaptic device and preparation method thereof Technical Field The invention relates to the technical field of semiconductor photoelectric devices and preparation methods thereof, in particular to a carbon-based van der Waals heterojunction photoelectric synaptic device and a preparation method thereof. Background The solar blind ultraviolet detection technology can detect the strong solar blind ultraviolet radiation signals generated in typical scenes such as lightning discharge, cosmic ray interaction and the like, and has important application value in the important fields such as space detection, natural disaster monitoring and the like, so that the solar blind ultraviolet detection technology becomes a key technology for realizing ultra-fast target identification, positioning and early warning. Currently, solar blind ultraviolet detectors based on wide bandgap semiconductor materials such as gallium nitride and aluminum nitride have made remarkable progress in response speed and device stability, but due to the working mechanism, the solar blind ultraviolet detectors can only serve as a sensor, and still rely heavily on a back-end circuit to perform signal processing and storage, so that the deep perception and intelligent recognition of targets are still difficult to complete in the face of rapid targets in a dynamic complex environment. With the urgent demands of intelligent monitoring on high-speed, low-energy consumption and intelligent sensing systems in the future, the traditional separated photoelectric system of detection, transmission and processing is difficult to be qualified, and development of a new generation of intelligent ultraviolet sensing devices capable of integrating photoelectric detection and brain-like calculation functions is needed. In recent years, the advent of synaptic-like optoelectronic devices has provided new possibilities for this direction. The device can simulate the response and memory process of biological synapses to external stimulus, and realize short-time plasticity (STP), long-time plasticity (LTP) and other synapse behaviors, so that the unification of perception and calculation is realized on a physical level. However, most of the existing photoelectric synaptic researches are focused on visible light and near infrared bands, and are mainly used for application scenes such as image recognition, voice signal processing and the like, and the exploration of the solar blind ultraviolet band is still blank. Therefore, how to design and prepare a solar blind ultraviolet photoelectric synaptic device, the synaptic function is introduced into ultraviolet detection, the defects of the traditional detector in the aspects of information processing and memory are overcome, and the solar blind ultraviolet photoelectric synaptic device has important practical significance and application value. Disclosure of Invention The invention aims to solve the technical problem of overcoming the defects of the prior art, and provides a carbon-based van der Waals heterojunction photoelectric synaptic device which has the sensing and memorizing functions of solar blind ultraviolet signals, can realize learning and forgetting processes under the light signals with different illumination intensities, durations and pulse numbers, and can be applied to solar blind ultraviolet detection. The invention further provides a preparation method of the carbon-based van der Waals heterojunction photoelectric synaptic device. In order to solve the technical problems, the invention adopts the following technical scheme: A carbon-based van der Waals heterojunction photoelectric synaptic device comprises a light absorbing basal layer, an interface function layer, a charge transport layer and an electrode structure; The light absorbing basal layer is monocrystalline or polycrystalline diamond and is used for absorbing photons of the solar blind ultraviolet band and generating photo-generated current carriers; The interface functional layer is positioned between the light absorbing substrate layer and the charge transport layer, and is used for capturing photogenerated carriers from the light absorbing substrate layer through interface defect energy levels and regulating and controlling the conductivity of the charge transport layer through an electrostatic field; the electrode structure includes a contact electrode in ohmic contact with the charge transport layer. As a further improvement of the technical scheme, the optical band gap of the light absorbing substrate layer is larger than 5.0eV, and the corresponding cut-off wavelength is smaller than 240nm. As a further improvement of the technical scheme, the interface functional layer comprises an hBN layer, and a deep energy level charge trap is arranged at the interface of the hBN layer and the light absorption substrate layer and is used for realizing nonvolatile storage of information. As a f