Interfacial diffusion enabled broadband response in photodetector based on InSe/GaAs heterojunction.

Infrared (IR) photodetectors play a crucial role in modern technologies due to their ability to operate in various environmental conditions. This study developed high-performance InSe/GaAs interdiffusion heterostructure photodetectors with broadband response using liquid-phase method. It is believed that an InGaAs layer and InSe have been formed at the interface through the mutual diffusion of elements, resulting in a detection spectral range spanning from 0.45 to 2.7 µm. Consequently, the InSe/GaAs photodetector exhibits notably low noise equivalent power of 6.21 × 10 WHz at 1000 Hz, high photoresponsivity () and detectivity () of 16.22 mA/W and 4.01 × 10 Jones under 0 V with 630 nm wavelength, respectively. At 1550 nm, it achieves a of 0.43 µAW and of 1.07 × 10 Jones under 0 V. This strongly suggests that the interdiffused InSe/GaAs heterostructure is a high performance and low-cost material for broadband responsive photodetectors.