A Self-Powered Bi-Directional SnS2/SnSe Heterostructure for an All-in-One Optoelectronic Logic Device

Abstract

The exploration of light in integrated circuits of computing systems has led to optoelectronic logic devices, where a single device can perform five fundamental logic operations: OR, AND, NOT, NAND, and NOR. However, the evolution of the logic function has been restricted by the fundamental components (photodetectors) of optoelectronic logic operations, which typically have a narrow spectral range and an unchangeable photoresponse. Herein, we have developed an SnS2/SnSe heterojunction-based photodetector demonstrating a bi-directional photocurrent response in the ultraviolet to infrared regions. This enables the device to switch between three distinct current states ("+1," "0," and "-1") based on the wavelength of incoming light. The wavelength-dependent bi-directional photoresponse allows the single device to perform five fundamental logic operations, NOT, OR, AND, NOR, and NAND, by varying input light power density and wavelength. The heterojunction of SnS2 (an n-type with a wide band gap in the visible region) and SnSe (a p-type material with a narrow band gap in the infrared region) leads to the extended spectral range and wavelength-dependent bi-directional photoresponse. The wavelength-dependent bi-directional photoresponse of the SnS2/SnSe photodetector has been utilized to create NOR, NAND, OR, and AND gates. The self-distinguishable photoresponse paves the way for more adaptable and efficient optoelectronic logic systems.