Strain-tuned mechanical, electronic, and optoelectronic properties of two-dimensional transition metal sulfides ZrS 2 : a first-principles study.

Two-dimensional semiconductor material zirconium disulfide (ZrS 2 ) monolayer is a new promising material with good prospects for nanoscale applications. Recently, a new zirconium disulfide (ZrS 2 ) monolayer with a space group of 59_Pmmn has been successfully predicted. Using first-principles calculations, this new monolayer ZrS 2 structure is obtained with stable indirect bandgaps of 0.65 eV and 1.46 eV at the DFT-PBE (HSE06) functional levels, respectively. Strain engineering studies on the ZrS 2 monolayer show effective bandgap modulation. The bandgap shows a nearly linear regularity from narrow to wide under strain (ranged from - 6 to + 8%). Young's modulus of elasticity of ZrS 2 along the tensile directions (x-axis and y-axis) is 83.63 (N/m) and 63.61 (N/m) with Poisson's ratios of 0.09 and 0.07, respectively. The results of carrier mobility show that the electron mobility along the y-axis can reach 1.32 × 10 3 cm 2  V -1  s -1 . Besides, the order of magnitude of the light absorption coefficient in the ultraviolet spectral region is calculated to reach 2.0 × 10 5  cm -1 for ZrS 2 monolayers. Moreover, the bandgap and band edge position of Pmmn-ZrS 2 can satisfy the redox potentials of photocatalytic water splitting by strain regulating. The results indicate that the new two-dimensional Pmmn-ZrS 2 monolayer is a potential material for photovoltaic devices and photocatalytic water decomposition.