Effect of scattering by native defects on electron mobility in modulation-doped heterostructures

Abstract
The effect of scattering by native defects on carrier mobility in modulation-doped heterostructures is calculated. The concentration of the defects is determined using the amphoteric native defect model. It is shown that the Fermi level induced reduction of the defect formation energy leads to an increased incorporation of native defects and reduced mobility in AlGaAs/GaAs inverted modulation-doped heterostructures. This new mechanism explains the experimentally observed difference in the values of electron mobilities in normal and inverted modulation-doped heterostructures. The effects of native defects on the carrier mobilities in heterostructures based on other semiconductor systems are also discussed.