High-Field Electron Transport and High Saturation Velocity in Multilayer Indium Selenide Transistors

Abstract

Creating a high-frequency electron system demands a high saturation velocity (upsilon(sat)). Herein, we report the high-field transport properties of multilayer van der Waals (vdW) indium selenide (InSe). The InSe is on a hexagonal boron nitride substrate and encapsulated by a thin, noncontinuous In layer, resulting in an impressive electron mobility reaching 2600 cm(2)/(V s) at room temperature. The high-mobility InSe achieves upsilon(sat) exceeding 2 x 10(7) cm/s, which is superior to those of other gapped vdW semiconductors, and exhibits a 50-60% improvement in upsilon(sat) when cooled to 80 K. The temperature dependence of upsilon(sat) suggests an optical phonon energy ((h) over bar omega(op)) for InSe in the range of 23-27 meV, previously reported values for InSe. It is also notable that the measured upsilon(sat) values exceed what is expected according to the optical phonon emission model due to weak electron-phonon scattering. The superior upsilon(sat) of our InSe, despite its relatively small (h) over bar omega(op), reveals its potential for high-frequency electronics, including applications to control cryogenic quantum computers in close proximity.