LAUSR

Using first-principles calculations, we investigate the photogalvanic effect (PGE) in photodetectors based on tungsten telluride/molybdenum telluride (WTe2/MoTe2) heterostructures. Our calculations reveal that the photocurrent generated by the PGE exhibits a highly asymmetric response along the armchair and zigzag directions, which is sensitive to the light polarization state and direction. Furthermore, a large photocurrent can be obtained for almost the entire visible range without the application of external source-drain voltage, thus avoiding the problem of dark current. The photocurrent in the armchair WTe2/MoTe2 photodetector is significantly enhanced compared to that in a basic WTe2 photodetector. It also exhibits a sinusoidal dependence on the polarization angle and chirality of the circular polarization in agreement with phenomenological models of the second-order photocurrent response to the electric field of the light. Furthermore, the WTe2/MoTe2 photodetector shows a high sensitivity to the polarization direction with an extinction ratio greater than 140 in the armchair direction. These advantageous properties suggest that WTe2/MoTe2 is a promising candidate material for photodetection applications.