Self-powered photodetector of GaN/Sc₂CCl₂ heterojunction with high carrier mobility and polarization sensitivity

This study is based on first-principles calculations to investigate the GaN/Sc₂CCl₂ heterojunction, and its electrical properties, optical properties, and photogalvanic effect under linearly polarized light are calculated. The GaN/Sc₂CCl₂ heterojunction is a narrow-bandgap semiconductor (1.15 eV) with excellent dynamic and thermal stability, featuring electron transfer from the GaN layer to the Sc₂CCl₂ layer. The heterojunction exhibits high carrier mobility (5670 cm² V^-1 s^-1) and significantly enhanced light absorption in the visible spectrum compared to its monolayer counterparts. For the GaN/Sc₂CCl₂ self-powered photodetector, the photocurrent shows little variation between linearly and elliptically polarized light, indicating low sensitivity to polarization type. Notably, at a photon energy of 1.2 eV, the photocurrent and extinction ratio reach maximum values of 12.78 a₀² per photon and 326.1, respectively, demonstrating excellent photoresponse and high polarization sensitivity. The GaN/Sc₂CCl₂ heterojunction can be used as an efficient photodetector material in fields such as photodetection. This research provides an effective strategy for designing high-performance heterojunction photodetectors.