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

Abstract

Density functional theory calculations are performed to explore the electronic and transport properties of monolayer α-GeTe under uniaxial strain. It is found that monolayer α-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 α-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 α-GeTe TFETs.

First-principles study of bipolar resistive memories based on monolayer α-GeTe

“…From calculation of the optimized ML α-GeTe energy band, as plotted in figure 1(b), ML α-GeTe is determined to be an indirect band gap semiconductor with a band gap of approximately 1.83 eV at the PBE level. This result is in good agreement with a previous experimental value (1.84 eV) [13].…”

“…In recent experiments, ML α-GeTe nanosheets have been prepared from matrix α-GeTe powder by an ultrasonic-assisted liquid phase peeling method [12]. These nanosheets can be stabilized in air and show superior electron mobilities [13,14], and the electron mobility at −8% uniaxial strain reaches 64422.04 cm 2 V −1 s −1 (x-direction) and 47793.87 cm 2 V −1 s −1 (y-direction), much superior to the electron mobility of phosphorene and single-layer MoS 2 [15]. Moreover, ML α-GeTe has a moderate band gap, anisotropic electronic properties and much smaller exfoliation energy [16], which makes it an excellent memory device material.…”

Strain Benefits of Monolayer α‐GeTe and its Application in Low‐Power Metal–Oxide–Semiconductor Field‐Effect Transistors

“…[ 34 ] Therefore, we believe that strain engineering has a perfect implementing platform for improving the physical properties of 2D materials and developing their new applications. [ 35 ] In this work, we would like to consider the benefits of strain engineering in α‐GeTe for traditional MOSFET applications and provide helpful guidance for experiment optimization.…”