Interfacial diffusion enabled broadband response in photodetector based on In₂Se₃/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 In₂Se₃/GaAs interdiffusion heterostructure photodetectors with broadband response using liquid-phase method. It is believed that an InGaAs layer and In₂Se₃ 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 In₂Se₃/GaAs photodetector exhibits notably low noise equivalent power of 6.21 × 10^-15 WHz^-1/2 at 1000 Hz, high photoresponsivity (R) and detectivity (D*) of 16.22 mA/W and 4.01 × 10¹¹ Jones under 0 V with 630 nm wavelength, respectively. At 1550 nm, it achieves a R of 0.43 µAW^-1 and D*of 1.07 × 10⁸ Jones under 0 V. This strongly suggests that the interdiffused In₂Se₃/GaAs heterostructure is a high performance and low-cost material for broadband responsive photodetectors.