Negative Photoconductivity Effect Based On Gallium Nitride-graphene Structure

Semiconductor materials play an extremely important role in the field of science and technology.Recently,photoelectric semiconductor materials draw a lot of interest.The preparation of photoelectric semiconductor devices with multi-functional integration and high-precision response has become a general development trend of photoelectric detection and optical computing.Since conventional positive photoconductive devices are difficult to meet people's needs,it is of great significance to study the negative photoconductive effect in order to make major breakthroughs in related fields such as photoelectric detection,optical chips and optical computing.However,few researchers have reported negative photoconductive effect devices with ultra-large current drop,large off/on ratio and ultra-fast response speed at room temperature.This study designed a graphene/CsPbBr₃-GaN/graphene structure for this research gap.The structure has a large current drop of 7.59?A,an off/on ratio of 32.6,and a response time of less than 113?s.When the ultraviolet laser with a wavelength of 360nm irradiates,the electrons at the top of the gallium nitride valence band are excited to the bottom of the conduction band,generating electron-hole pairs.The photogenerated electrons in the conduction band begin to move due to the difference in the contact surfaces on both sides,generating an electron current.The hole current generated under the bias voltage is opposite to the photogenerated electron current,which achieves the effect of current reduction.This research uses this structure to fabricate photoelectric “NOT” gates and photoelectric “TERNARY ”gates.Among them,the photoelectric “NOT” gate realizes the “NOT” logic with light as input and voltage as output,and has a fast and stable response.The photoelectric“TERNARY”gate enriches the modes for realizing“TERNARY”output,and improves the application value of the combination of positive photoconductive devices and negative photoconductive devices.This research provides a strategy to solve the scarcity of negative photoconductive devices,which may promote the integration of optoelectronic devices and the development of the semiconductor industry.