Enhanced photogalvanic effect in Janus PtSSe-HfSSe lateral heterojunctions

The enhancement of photogalvanic effect (PGE) is vital for the application of optoelectronics. We use the ab initio quantum transport method to study the possible enhancement of PGE by importing a lateral PtSSe-HfSSe heterojunction. Under irradiation of linearly polarized light with photon energies (Eph) of 0.8–6.2 eV, the overall increase ratio of the PGE photocurrent is over 20/50 along the armchair/zigzag direction. The lateral PtSSe-HfSSe photodetector along the armchair direction exhibits a better photon response than the photodetector along the zigzag direction. The maximal PGE photocurrent is 42.26 a02/photon at Eph = 2.0 eV, and the highest extinction ratio is 2.5 × 104 at Eph = 1.6 eV. Our study indicates that the lateral PtSSe-HfSSe heterojunction is a favorable candidate for optoelectronics.