Band gap and electronic properties of molybdenum disulphide under strain engineering: density functional theory calculations

In this paper, we study the effect of uniaxial and biaxial strain on the structural and electronic properties of MoS monolayers by first-principle calculations based on density functional theory. Our calculations show that the bond length between Mo and S atoms depends linearly on the strain. At the equilibrium state, MoS has a direct band gap of 1.72 eV opening at the K-point. However, an indirect–direct band gap transition has been found in MoS monolayer when the strain is introduced. MoS becomes a semiconductor with an indirect band gap when the uniaxial strain or the biaxial strain . Under biaxial strain, a metal–semiconductor transition occurs at of elongation. The indirect character and phase transition will largely constrain application of MoS monolayer to electronic and optical devices.