Multifunctional UV photodetect-memristors based on area selective fabricated Ga2S3/graphene/GaN van der Waals heterojunctions†

Abstract

Multifunctional devices based on van der Waals heterojunctions have drawn significant attention owing to their portable size, low power consumption and various application scenarios. However, high fabrication equipment requirements, complex device structures and limited operating conditions hinder their potential value. Herein, multifunctional UV photodetect-memristors based on Ga₂S₃/graphene/GaN van der Waals heterojunctions via area selective deposition have been proposed for the first time. The Ga₂S₃/graphene/GaN heterojunctions are firstly grown via area selective deposition (ASD) without a mask plate or lithography process. And the corresponding molecular dynamics (MD) and density functional theory (DFT) simulation further confirmed its feasibility and physical properties. Subsequently, multifunctional devices based on Ga₂S₃/graphene/GaN heterojunctions are fabricated accordingly, and exhibit ultrafast (<80 μs) response at 0 V and stable, highly sensitive (1150.4 A W⁻¹) memory features at 3 V. Here, the huge hole barriers formed on the two edges of graphene set the foundation of trapping and detecting light-induced carriers. Afterwards, handwriting numeral recognition tasks are carried out based on the performance extracted from the device and a simplified noise filtering and improved recognition accuracy system is proposed, confirming its application potential in the artificial intelligence area. This study proposes a practical way to grow large-size 2D materials selectively, shows the valuable application potential of p–g–n heterojunctions in various application fields, and expands an innovative path of device development in the post-Moorish era.