Nonmonotonous Electron Mobility in Double Quantum Well Pseudomorphic High Electron Mobility Transistor Structure

Non-monotonic mobility $\mu$ of electrons is obtained in a pseudomorphic GaAs/InxGa1-x As high electron mobility transistor having a double quantum well structure with asymmetric doping concentrations in the outer barriers. A dip in ${\mu}$ occurs at the resonance of subband states because of the shift of the subband wave functions, which affects the subband mobilities limited by interface roughness scattering. The dip in $\mu$ amplifies with increase in the asymmetry of the width of wells.