Abstract
Multispectral detection technology captures characteristic spectral information across various wavebands, exhibiting substantial application potential. However, most currently reported multispectral photodetectors rely on intricate dual- or multi-junction structures, severely limiting material thickness, doping concentration, and band alignment design, thereby impeding widespread adoption. In this study, a bias-tunable multispectral photodetector featuring a straightforward single-junction design is introduced. The device comprises a Te(x)Se(1-) (x)/GaN homo-type heterojunction with a unidirectional barrier. This structure effectively suppresses the majority-carrier dark current, yielding a low reverse dark current of ≈10(-12) A and a high rectification ratio of up to 10(5). By adjusting the bias polarity and magnitude, the spectral response range of the device can be broadened from ultraviolet (UV) to short-wave infrared. Notably, the photodetection performance is exceptional: at 0 V bias, the device exhibits a responsivity of 0.25 A W(-1) and a specific detectivity of 5.04 × 10(11) cm Hz(1/2) W(-1) under 365 nm illumination; at -2 V bias, it achieves a responsivity of 0.58 A W(-1) and a specific detectivity of 2.64 × 10(9) cm Hz(1/2) W(-1) under 1060 nm illumination. Leveraging the bias-tunable spectral response characteristic of the device, proof-of-concept imaging is successfully demonstrated. This research presents a simplified and economical method for fabricating multispectral photodetectors.