Single-Layer InGeS: Robust direct Bandgap, super high electron Mobility, long-lived Carriers, and Ohmic contact for Next-Generation Field-Effect transistors

Abstract

Two-dimensional (2D) materials holding appropriate bandgaps, high carrier mobility, and long carrier lifetime require to be urgently explored as electronic devices such as field effect transistors (FETs) become more and more miniaturized. Herein, single-layer (SL) InGeS is thoroughly investigated using first-principles calculations. Theoretical results confirm SL InGeS has nice thermal and dynamical stability at 300 K. SL InGeS holds a direct bandgap of 1.28 eV by HSE06, and its electrons and holes are inherently located at different atomic regions. In the visible range, SL InGeS displays a maximum optical absorption of ∼ 5 × 10⁵ cm⁻¹, surpassing that of most known 2D materials. Furthermore, SL InGeS possesses high electron mobility (∼11100 cm² V⁻¹ s⁻¹) and relatively low hole mobility (∼1000 cm² V⁻¹ s⁻¹), and its carrier lifetime is as long as 4.99 ns. In addition, an Ohmic contact is designed in the graphene/InGeS heterojunction, implying small current resistance. In brief, all these scientific findings promise SL InGeS is a hopeful candidate in ultrathin FET devices.