Photoluminescence from the quasi-two-dimensional electron gas at a single silicon δ-doped layer in GaAs

Radiative recombination of quasi-two-dimensional electrons with photocreated holes is reported in single silicon δ-doped layers in GaAs. These holes are confined within the GaAs surface and the potential induced by the doping spike, which is repulsive for holes. Replacing the GaAs surface by an ${\mathrm{Al}}_{0.33}$ ${\mathrm{Ga}}_{0.67}$As/GaAs heterointerface the photoluminescence from the δ-doping spike is drastically enhanced. It is shown by photoluminescence and Raman spectroscopy that the density of carriers created by cw photoexcitation can be made sufficiently high in the heterostructure to modify the actual shape of the doping-induced potential well.