Nonlinear electron mobility due to asymmetric doping in V-shaped double quantum well FET structure

The nonlinear electron mobility µ is obtained in an asymmetric doped V-shaped double quantum well field-effect transistor (FET) structure based on AlxGa1-xAs. The nonmonotonic oscillation of µ occurs owing to intersubband interactions through the ionized impurity scattering when two subbands are occupied. The magnitude of µ is dominated by the alloy disorder scattering because of the alloy channel system. The oscillatory enhancement of the low-temperature mobility increases by increasing the difference of doping concentrations in the extreme barriers. The wavy nature of µ is also enhanced through a decrease in the height of the V-shaped potential and an increase in the barrier width at the center. The combined effect of relocation of subband wave functions in the wells and occurrence of anticrossing of subband energy levels near the resonance of subband states of the wells changes the intrasubband and intersubband scattering rate matrix elements significantly, thus causing nonlinear µ. The results of mobility obtained by us can be utilized to analyze the fine-tuning of channel conductivity in V-shaped quantum well FET structures.