Impact of uniaxial strain on the electronic and transport properties of monolayer α-GeTe

Density functional theory calculations are performed to explore the electronic and transport properties of monolayer alpha-GeTe under uniaxial strain. It is found that monolayer alpha-GeTe has an indirect band gap of 1.75 eV and exhibits worthwhile anisotropy along with high electron mobility. The electron mobilities reach 1974 cm(2) . V-1 . s(-1) and 1442 cm(2) . V-1 . s(-1) along the zigzag and armchair directions, respectively. When uniaxial strain is applied, our results show an appreciable strain sensitivity of electron mobility. The electron mobility dramatically increases by an order of magnitude around a special strain due to the shifts of conduction band minimum. In addition, we also construct a double gate tunneling field effect transistor (TFET) with a channel of monolayer alpha-GeTe. The steeper sub-threshold swing and higher ON/OFF ratio are observed by applying tensile strain to the channel. As a result, it indicates that the appropriate strain can significantly improve the performance of alpha-GeTe TFETs.