Research on GaN micro-nano structures and their optoelectronic devices
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Research on GaN micro-nano structures and their optoelectronic devices

Posted Date: 2024-01-16

Nitride semiconductors have the advantages of wide band gap, tunability, and high photoelectric conversion efficiency. They have broad application prospects in the fields of ultraviolet sensors, power devices, radio frequency electronic devices, LED lighting, displays, deep ultraviolet sterilization and disinfection, lasers, and storage. Considered a promising luminescent material.

As a wide-bandgap semiconductor material with superior performance, GaN has important research significance and application value in the field of ultraviolet detection. Compared with bulk materials, GaN micro-nano structures have a larger specific surface area and lower carrier scattering, which is not only conducive to studying the physical mechanism of ultraviolet detection, but is also an ideal structure for preparing low-dimensional, high-performance ultraviolet detectors.

At the recently held 9th International Third Generation Semiconductor Forum (IFWS) & 20th China International Semiconductor Lighting Forum (SSLCHINA) "Nitride Semiconductor Solid-State UV Technology" branch meeting,Wang Xingfu, a researcher at South China Normal University, gave a keynote report titled "Research on GaN Micro-Nano Structure and Its Optoelectronic Devices".

GaN micro-nano devices involve nanowire array LEDs, nanowire flexible LEDs, nanowire lasers, nanowire integrated optical waveguides, etc. Due to the difficulty in achieving effective control of nanometer size, spatial density, morphology, structure, etc., nanomaterials and devices are limited. development and application.

The report introduces the preparation method, photoelectric properties and ultraviolet detection device of a new type of GaN micro-nano structure. The study uses Si patterned substrate lateral epitaxy and electrochemical exfoliation to prepare an ordered GaN micro-nano array structure on a heterogeneous substrate. This structure has excellent light field confinement and carrier confinement. The nanowire has a low The non-radiative recombination rate and the higher radiative recombination rate indicate that the transferred nanowires have fewer defects.

Based on the obtained high-quality gallium nitride array, a high-performance ultraviolet detector with low dark current and high photocurrent was prepared. The low dark current of the device is attributed to the electron depletion on the surface and the electron blocking effect of the Schottky barrier, while the device exhibits an ultra-high ohmic type photocurrent due to the effect of photoelectron tunneling when illuminated. This extremely low Schottky type dark current and high ohmic type photocurrent reflect the transition of electron emission from TE mode to TFE mode. GaN micro-nano UV detectors overcome the limitations of low UV absorption, low quantum efficiency, and low responsivity in conventional GaN detectors, providing new ideas for the realization of new low-power, high-performance UV detectors.

The report shared in detail the research results and research progress on the preparation of GaN micro-nano arrays by selective lateral epitaxy and the preparation of GaN micro-nano structures by electrochemical stripping. Among them, the preparation of GaN micro-nano arrays by selective lateral epitaxy involves selective lateral epitaxy, epitaxial dislocation bending, single micron line UV detection, array micron line UV detection, AlN surface passivation, and chip packaging. The preparation of GaN micro-nano structures by electrochemical stripping involves PIN structure vs. micro-nano array structure device, electrochemical stripping, epitaxial structure design, electrochemical selective corrosion principle, self-supporting micron line array, micron array ultraviolet detection, and N polar plane Strong surface potential, etc. The report points out that passivating GaN surface defects is beneficial to improving the photoelectric performance of the device; the in-situ AlN passivation layer improves the metal-semiconductor contact barrier and suppresses dark current





Review Editor: Liu Qing


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