Carrier density distribution in modulation doped GaAs-AlxGa1−xAs quantum well heterostructures

A theoretical model for the distribution of charged carriers at the interface of a doped Al x Ga 1− x As-undoped GaAs heterostructure is evaluated. Assuming a triangular potential well at the interface, we obtain numerically, curves describing the Fermi energy, depletion width in the alloy, and average separation of impurities and carriers, and the electron density at the interface as functions of alloy layer composition and doping level. The results obtained can be applied to multiple heterointerface quantum well heterostructures and superlattices as well. Carrie concentration profile data on a 51-layer modulation doped QWH grown by MOCVD are presented and are discussed using the results of the model.