Interface roughness scattering-limited electron mobility in AlAs/GaAs and Ga0.5In0.5P/GaAs wells

Interface roughness scattering-limited electron mobility is calculated for AlAs/GaAs and Ga0.5In0.5P/GaAs wells taking into account the effects of finite barrier potential, extension of the wave function into the barrier layer, energy band nonparabolicity, and screening of the scattering potential. The mobility in AlAs/GaAs wells varies with the well width L as Ln(n=4.7–4.8), but the variation cannot be fitted to a similar relation for Ga0.5In0.5P/GaAs wells. Experimental results for both the systems may be explained with an asperity height between 2.83 and 5.67 Å, and a correlation length smaller than 170 Å. It is concluded that the larger experimental mobility in Ga0.5In0.5P/GaAs wells is due to the smaller barrier potential in this system.