Radiative transitions associated with hole confinement at Si δ-doped planes in GaAs

Spatially direct radiative processes involving δ-doped planes are reported. The transitions are observed in structures that were designed to strongly confine holes to the δ planes. Two structures, δ-plane superlattices and center-δ-doped quantum wells were used. In each case low-dimensional features associated with the modified subband structure were observed. The δ-plane superlattices exhibit electron minibands that may be ‘‘tuned’’ by control of the δ-plane spacing. Photogenerated holes are trapped in such structures and are unable to transport in the growth direction at low temperatures. The δ-doped quantum wells show grossly shifted confined states; for the heaviest doped well measured, the normal ordering of the n=1 light-hole and the n=2 heavy-hole states is reversed. Self-consistent calculations are reported, which account for the optical data in both types of structure.