RADIATIVE TRANSITIONS ASSOCIATED WITH HOLE CONFINEMENT AT SI DELTA-DOPED PLANES IN GAAS

Spatially direct radiative processes involving delta-doped planes are reported. The transitions are observed in structures that were designed to strongly confine holes to the delta-planes. Two structures, delta-plane superlattices and center-delta-doped quantum wells were used. In each case low-dimensional features associated with the modified subband structure were observed. The delta-plane superlattices exhibit electron minibands that may be "tuned" by control of the delta-plane spacing. Photogenerated holes are trapped in such structures and are unable to transport in the growth direction at low temperatures. The delta-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.