Photoluminescence-excitation-correlation spectroscopic study of a high-density two-dimensional electron gas in GaAs/${\mathrm{Al}}_{0.3}$${\mathrm{Ga}}_{0.7}$As modulation-doped quantum wells

We reported the photoluminescence properties of a high-density electron gas in GaAs-${\mathrm{Al}}_{0.3}$${\mathrm{Ga}}_{0.7}$As modulation-doped quantum wells by using cw and subpicosecond excitation correlation photoluminescence techniques. The gain or loss of photoluminescence intensity was found to be closely related to the excitation intensity vs carrier concentration. There is a significant distinction between the relaxation processes of minor carriers and of the doped two-dimensional electron gas in the wells. The former takes about a constant time duration (∼70 ps), while the latter is sensitive to the excitation intensity, and theoretically can be attributable to phonon reabsorption.