ELECTRONIC-PROPERTIES OF A SEMICONDUCTOR SUPER-LATTICE .1. SELF-CONSISTENT CALCULATION OF SUBBAND STRUCTURE AND OPTICAL-SPECTRA

The subband structure of a heavily doped n-type GaAs-Ga1-xAlxAs superlattice is calculated. A band bending effect caused by charge transfer from the GaAs-Ga1-xAlxAs to GaAs layers is taken into account self-consistently in the Hartree approximation. When the wavefunction along the superlattice direction is rather localized, the band bending effect is crucial especially in the case of modulation doping where only the GaAs-Ga1-xAlxAs layer is heavily doped and the GaAs layer remains undoped. Calculated results are in good agreement with recent experiments. Many-body effects such as exchange and correlation are studied in the density-functional formulation, but shown to be unimportant. Intersubband optical absorptions are also investigated. A local field effect can shift resonance energies to higher energy side considerably. © 1979, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.