Photo-Tailored Band Engineering for Optoelectronic Logic Gates via In -Situ Grown SnS/SnS₂ Heterojunction

An optoelectronic logic gate (OELG) device with fast transmission and precise computation is invaluable for next-generation optoelectronic architectures. However, due to the unidirectional carrier transport in fundamental photoelectrical components, realizing multiple logic functions on a single device still remains challenging. In this work, we designed an OELG photodetector via in situ-grown SnS/SnS₂ lateral heterojunction sulfidation technology. By virtue of phototailored band engineering, the device features an ultrafast and repeatable wavelength-dependent bipolar photoresponse, enabling a reversible carrier transport pathway compared to traditional van der Waals heterojunctions. The device exhibits superior and stable optoelectronic performance: specific detectivity (D* = 1.5 × 10¹¹ Jones), photoresponsivity (R = 43.5 mA/W), a fast response speed of 16.8 ms, and a high on/off ratio of 1675. Notably, seven basic reconfigurable logic functions (AND/OR/NOT/NAND/NOR/XOR/XNOR) and multilayer composite logic operations, like Y = (A + B) × C, are successfully demonstrated based on a single heterojunction photodetector (PD). Furthermore, we present an ultraprecision optical communication system (bit error rate <10^- 6) for encoding ASCII characters. This work not only provides a novel tailor-made strategy for reconfigurable OELGs, but also highlights new opportunities for intelligent optoelectronics in next-generation light computing applications.