Semiconductor-semimetal transition of MoTe2 monolayer modulated by charge-injection and strain engineering

Abstract

Because of the small energy difference between semiconducting 2H-MoTe2 and semimetallic 1T′-MoTe2, fast on/off switching through phase transition could be realized in MoTe2-based devices. In this work, first-principles calculations are done to study the effects of charge injection and strain engineering on the phase transition between 2H- and 1T′-MoTe2. The transition barrier is dramatically lowered by the experimentally accessible charge injecting (0.05 e/f.u. for holes or 0.03e/f.u. for electrons at 300 K). As for strain engineering, the transition barrier is lowered by 26.37%, and the transition time is shortened by 4 orders of magnitude at a tensile strain of 3.08% along armchair direction. At a compressive strain of 3.01% along zigzag direction, the transition barrier is lowered by 24.18% with the shortened transition time. Furthermore, the synthetic effect of charge doping and strain engineering is demonstrated to lower the threshold transition condition and modulate the 2H-1T′ phase transition.