Reconfigurable Phototransistors Driven by Gate-Dependent Carrier Modulation in WSe2/Ta2NiSe5 van der Waals Heterojunctions

Reconfigurable field-effect transistors (RFETs) offer notable benefits on electronic and optoelectronic logic circuits, surpassing the integration, flexibility, and cost-efficiency of conventional complementary metal-oxide semiconductor transistors. The low on/off current ratio of these transistors remains a considerable impediment in the practical application of RFETs. To overcome these limitations, a van der Waals heterojunction (vdWH) transistor composed of WSe₂/Ta₂NiSe₅ has been proposed. By modulating a single back-gate voltage and source-drain voltage inputs, the transistor achieves a switchable polarity configuration and bidirectional rectification, making it capable of functioning as a gate-controlled bidirectional half-wave rectifier. The proposed RFET exhibits tunable positive/negative photovoltaic responses, advanced optoelectronic performance, and a gate-voltage-dependent reversal of the photodetector position. Detailed energy band diagram studies have shown that the reconfigurability of the device arises from carrier blockage resulting from the type-I band structure and carrier injection modulated by gate-dependent Schottky barriers. Consequently, the reconfigurable WSe₂/Ta₂NiSe₅ vdWH holds significant promise for advanced multifunctional optoelectronic device applications.