A Novel Approach for the Fabrication of Polarization-Selectivity UV Photosynapse Devices With PdSe₂/ a-plane GaN Heterostructures.

Abstract

High polarization-selectivity UV photodetectors with multifunctional integration play a crucial role in the next-generation optoelectronic devices. However, weak and unruly dichroism radio (DR) of naturally anisotropic materials seriously restricts the detection accuracy and practical application, especially for wide-bandgap materials with rough surfaces and inherent weak anisotropy. In this work, a novel approach for the polarization-selectivity UV photosynapse devices with PdSe₂/ a-plane GaN heterostructures has been proposed. A simple pre-selenization treatment is employed to enhance the anisotropy (DR = 16) and crystallinity of PdSe₂, addressing the current limitation of insufficient anisotropy (DR<5) that hinders the practical application. The devices take advantage of inherent anisotropic materials and synergistic effect from the in situ growth of PdSe₂ on a-plane GaN, resulting in an enhancement of anisotropic photocurrent ratio from 1. 6 to 10.7. Thanks to the synergistic effect of the whole device architecture, the devices reveal an ultra-long relaxation time of up to 282s and effectively improve the details of image recognition, speed up calculations, and accurate detection capabilities. The combination of high polarization-selectivity, accurate detection, ultra-long memory, and outstanding data processing capabilities establishes the photodetector as a promising candidate for the on-chip integration of multi-information carrying, processing, and neuromorphic computing.