2D hole gas mobility at diamond/insulator interface

The hole mobility of two-dimensional (2D) gas at (001) and (111) diamond/insulator interfaces is investigated theoretically and compared with experimental data from the literature. It is shown that the surface impurity scattering is the limiting mechanism at room temperature in most of the H-terminated diamond field effect transistors, where the negative charges created by transfer doping are in the vicinity of the 2D gas. By repelling the negative charges at the metal/insulator interface, as recently reported for the (111) h-BN/diamond interface, we demonstrate that it is possible to achieve high mobility values of the order of 3000 cm2/V s when a pure phonon scattering occurs. This work confirms the potential of two-dimensional hole gas diamond field effect transistors for high power and high frequency applications.