Superior AlGaN/GaN‐Based Phototransistors and Arrays with Reconfigurable Triple‐Mode Functionalities Enabled by Voltage‐Programmed Two‐Dimensional Electron Gas for High‐Quality Imaging

Abstract

High‐quality imaging units are indispensable in modern optoelectronic systems for accurate recognition and processing of optical information. To fulfill massive and complex imaging tasks in digital age, devices with remarkable photoresponsive characteristics and versatile reconfigurable functions on a single device platform are in demand but remain challenging to fabricate. We report an AlGaN/GaN‐based double‐heterostructure, incorporated with a unique compositionally graded AlGaN structure to generate a channel of polarization‐induced two‐dimensional electrons that can be modulated to control electron separation, collection, and storage process in the channel of the fabricated phototransistor. As a result, when exposed to different light sources, the device shows reconfigurable multifunctional photoresponsive behaviors with superior characteristics owing to the successful programming of the 2DEGs by the combined gate and drain voltage inputs. A self‐powered mode with a responsivity over 100 A/W and a photoconductive mode with a responsivity of ∼108 A/W were achieved, with the ultimate demonstration of a 10×10 device array for imaging. More intriguingly, the device can be switched to photoelectric synapse mode, emulating synaptic functions to denoise the imaging process while prolonging the image storage capability. Demonstrating three‐in‐one operational characteristics in a single device offers a new path toward future integrated and multifunctional imaging units.This article is protected by copyright. All rights reserved