Phase transition, effective mass and carrier mobility of MoS2 monolayer under tensile strain

We report a computational study on the impact of tensile strain on MoS2 monolayer. The transition between direct and indirect bandgap structure and the transition between semiconductor and metal phases in the monolayer have been investigated with tensile strain along all direction configurations with both x-axis and y-axis components epsilon(xy) (epsilon(x) and epsilon(y)). Electron effective mass and the hole effective mass are isotropic for biaxial strain epsilon(xy) = epsilon(x) = epsilon(y) and anisotropic for epsilon(xy) with epsilon(x) not equal epsilon(y). The carrier effective mass behaves differently along different directions in response to the tensile strain. In addition, the impact of strain on carrier mobility has been studied by using the deformation potential theory. The electron mobility increases over 10 times with the biaxial strain: epsilon(x) = epsilon(y) = 9.5%. Also, the mobility decreases monotonically with the increasing temperature as mu similar to T-1. These results are very important for future nanotechnology based on two-dimensional materials. (C) 2014 Elsevier B.V. All rights reserved.