Complexly electronic structure induced largely tunable anisotropic mobility for monolayer GeTe by uniaxial strain

Abstract

In this work, a monolayer GeTe has been systematically investigated in terms of the electronic property and carrier mobility under the uniaxial strain by using the first-principles calculation. The developed monolayer GeTe exhibits an indirect bandgap of 1.67 eV along with degeneracy at Γ point. A uniaxial strain causes a large dispersion in the valance band, resulting in anisotropy of the effective mass. The asymmetric carrier mobility is obtained for the pristine monolayer GeTe that exhibits inversion under −2% uniaxial strain. Specifically, at −8% uniaxial strain, inverted carrier mobility resulted in the electron mobility of 690 (x-direction) and 3184 times (y-direction) as high as the corresponding hole mobility. The electron mobility at −8% uniaxial strain reaches 64422.04 cm2/Vs (x-direction) and 47793.87 cm2/Vs (y-direction) i.e. superior than the electron mobility of phosphorene and monolayer MoS2. The strain-controlled outstanding carrier mobility can be derived from the high dispersion of energy band and low deformation potential under strain. The controlled excellent carrier mobility suggests that the developed monolayer GeTe can be served as n-type or p-type semiconductors, which leads to potential applications in electronics, optoelectronics and nanosized mechanical sensors.