Excellent Nonlinear Optical Effects in MoS2/CrOCl Heterojunction

Abstract

Recent years, strong nonlinear optical (NLO) effects found in two-dimensional (2D) materials have attracted increasing interest due to the promising applications in photonics and optoelectronics. Stacking 2D materials to form vdW heterojunctions is an efficient way to manipulate physical properties. Recently, MoS 2 /CrOCl heterojunction with high carrier mobility, high on/off ratio and high air stability, was successfully obtained in experiments. Therefore, the NLO properties of this heterojunction are an interesting and urgent issue to be explored. Here, the NLO effects, including second harmonic generation (SHG) and bulk photovoltaic effect (BPVE), of the MoS 2 /CrOCl heterojunction were investigated by first-principles calculations. The BPVE response in the heterojunction is very strong throughout the visible light region and the shift photoconductivity reaches to -1225.8 μA/V 2 when incident light wavelength is 469.7 nm, which is dozens of times larger than that of traditional bulk BPVE materials, such as BaTiO 3 (30 μA/V 2 ) and PbTiO 3 (50 μA/V 2 ). Our results suggest the MoS 2 /CrOCl heterojunction has promising applications in optoelectronic devices, especially in photovoltaic devices.