Preparation and Characterization of GaAs Doping Superlattices

Abstract

The space-charge induced periodic modulation of the energy bands in GaAs doping superlattices grown by molecular beam epitaxy leads to a confinement of electrons and holes in alternate layers (indirect gap in real space). Due to the effective spatial separation the recombination lifetimes of excess carriers are enhanced and large deviations of electron and hole concentrations from thermal equilibrium become quasi-stable. As a result, doping superlattices exhibit unique tunable electronic properties. This fundamental difference from familiar semiconductors is exemplified by results on the tunability of bipolar conductivity and of the two-dimensional subband structure by carrier injection via selective electrodes and by photoexcitation.

This work was sponsored by the Bundesministerium für Forschung und Technologie of the Federal Republic of Germany.