Wavelength-Dependent Bipolar Photoresponse Enabled All-in-One Optoelectronic Logic Gates on Epitaxial GaSe/GaN 2D-3D Hybrid Heterojunctions

The growing demand for information processing and transmission requires high-performance device platforms for efficient computing and telecommunications. Optoelectronic logic devices are promising candidates for next-generation in-sensor computing units, owing to their intrinsically high optical gain and transmission speed. However, reliable all-in-one optoelectronic logic gates that integrate all logical operations into a single device are still lacking. Herein, a new architecture is reported for an all-in-one device fabricated using a large-scale epitaxial GaSe/GaN heterojunction. The functioning mechanism of such devices is based on the unique wavelength-dependent bipolar photoresponse originating from the competition between the photovoltaic and photothermoelectric effects, which can be tuned by film thickness. GaSe films are epitaxially grown on a GaN substrate by physical vapor deposition in an ultrahigh-vacuum environment, which guarantees an atomically clean interface. The device demonstrates superior optoelectronic performance with a detectivity of 4 × 10¹² Jones and an on-off ratio of 4 × 10³. All seven logic gates, “AND,” “OR,” “NOT,” “XOR,” “NOR,” “XNOR,” and “NAND,” have been performed via all optical modulation within a single device. This study provides a novel approach for fabricating all-in-one multifunctional optoelectronic gates.