Simultaneous bidirectional rectification and fast photodetection in Ta₂NiSe₅/ReSe₂ heterojunctions via gate voltage regulation

Two-dimensional (2D) van der Waals heterojunctions have attracted tremendous attention due to their excellent electronic and optoelectronic properties. However, conventional unipolar 2D heterostructures generally exhibit unidirectional rectification behavior and rarely possess bidirectional rectification characteristics, which limits the reusability of the devices. Herein, we designed a bidirectional rectification photodetector based on Ta₂NiSe₅/ReSe₂ heterojunctions, leveraging the ambipolar nature of ReSe₂ and the narrow bandgap of Ta₂NiSe₅. This unique material combination breaks through the unidirectional rectification bottleneck of conventional 2D heterojunction. This work reveals that photogenerated carrier tunneling can be simultaneously regulated at both the heterojunction interface and drain Schottky contact under gate voltage modulations, which is analyzed via transport current fitting and energy band analysis. Results show rectification ratios up to ∼10⁴ and ∼10⁵ under ±60 V gate voltages, respectively. Notably, it exhibits photodetection performance over 520–980 nm, with fast microsecond level photoresponse. This work demonstrates great application prospects of the Ta₂NiSe₅/ReSe₂ heterojunction photodetector in advanced optoelectronics, providing a new strategy for high-performance, multifunctional photodetectors.