The carrier mobility of monolayer and bulk GaS: from first-principles calculations

Metal chalcogenides have become popular materials for next-generation electronic devices due to their wide band gap and excellent transport properties. Specifically, two-dimensional metal chalcogenides also have outstanding physical properties. For electronic devices, the carrier mobility is a key parameter because it affects the material conductivity and the response time. As a member of metal chalcogenides, GaS has attracted the attention of scholars. In this work, by using first principles calculations and the Wannier function interpolation, the electronic and phonon properties, the electron-phonon interaction, the scattering rate, and the carrier mobility of monolayer and bulk GaS are systematically studied. The results show that GaS is a semiconductor and both monolayer and bulk GaS are dynamically stable. The LO phonon modes at long wavelengths strongly affect the carrier migration in GaS. We give the carrier mobility of monolayer and bulk GaS as a function of temperature (100 < K < 500). In addition, we compare the carrier mobility of GaS with several other metal chalcogenides (monolayer and bulk InSe, monolayer GeS, and monolayer GeSe) at 300 K. The results show that an increase in temperature leads to a decrease in the carrier mobility and the electron (hole) mobility of monolayer and bulk GaS is 10.85 cm² V^-1 s^-1 (0.22 cm² V^-1 s^-1) and 1229.79 cm² V^-1 s^-1 (9.28 cm² V^-1 s^-1), respectively. By comparing with the carrier mobility of other chalcogenides, we can find that the electron mobility of bulk GaS is the highest, which indicates that bulk GaS has high application potential.