Self-driven photodetector based on a GaSe/MoSe2 selenide van der Waals heterojunction with the hybrid contact

The restacking of stripped two-dimensional material into a van der Waals heterojunction provides a promising technology for high-performance optoelectronic devices. This paper presents a self-driven photodetector composed of p-GaSe/n-MoSe2. The hybrid contact is directly formed between the electrode and the heterojunction, which considerably improves the photovoltaic effect. In addition, the Schottky barrier between the semiconductor and metal electrodes creates a built-in electric field, which enhances the self-driven performance of the device. The as-fabricated photodetector has the high responsivity of 0.169 A W−1 at zero bias and the specific detectivity of 6.6 × 1011 Jones. When bias was applied, a responsivity of 6.81 A W−1 and a specific detectivity of 2.8 × 1013 Jones have also been obtained. This work demonstrates that selenide van der Waals heterojunctions based on two-dimensional materials have great potential for future electronic and optoelectronic applications.