New Challenges for Deltalike Confinement of Impurities in GaAs

Abstract

We review some aspects of deltalike confinement of isoelectronic and dopant impurities in (001) GaAs. Nucleation, redistribution and relaxation are the important processes for achieving structural perfection and hence the resulting electronic properties for both the generation of quantum dots and wires by self-organized molecular beam epitaxy (MBE) growth and high-density incorporation up to one monolayer. In detail, we discuss the fabrication and properties of InAs quantum dots and wires, of Si doping wires in GaAs, and of Si-delta-doped GaAs with highly improved free-carrier density. The most important issue in our experiments is that the impurity species must be deposited not continuously, but in pulses to ensure ordered incorporation on lattice sites along step edges.