Rashba spin splitting in inversion layers on p-type bulk InAs

The dependence of the spin-orbit interaction on electron density in inversion layers of metal-oxide-semiconductor field-effect transistors on p-type InAs is studied by magnetotransport at liquid-helium temperatures. We observe beating patterns in the Shubnikov-de Haas oscillations, which manifest the Rashba effect in a triangular surface potential. Taking subband nonparabolicity into account we evaluate Rashba parameters alpha that increase with electron density n(s) reaching a value alpha = 3 x 10(-11) eV m at densities n(s)greater than or equal to 2.2 x 10(12) cm(-2) Implications for the spin-dependent transport in spin-polarized high-electron-mobility transistors utilizing InAs quantum wells are discussed.