Strain‐Engineered Ultrahigh Mobility in Phosphorene for Terahertz Transistors

Carrier mobility is a key parameter for the operation of electronic devices as it determines the ON state current and switching speed/frequency response of transistors. 2D phosphorene is considered as a potential candidate for field‐effect transistors due to its high mobility. Here it is proposed to further enhance the carrier mobility of phosphorene and device performance via strain engineering. A systematic ab initio investigation on the anisotropic electronic structure of few‐layer phosphorene reveals that the monolayer under 7.5–10% strain along zigzag direction shows an exceptional carrier mobility of ≈10 6 cm 2 V −1 s −1 , which is 10 times higher than the strain‐free case. The simulated device performance shows that strain‐engineered phosphorene–based field‐effect transistors demonstrate a cut‐off frequency of ≈1.14 THz with a gate length of 1.0 micron and 112 THz with a sub‐10 nm gate length.