PHOTOLUMINESCENCE STUDIES ON VERY HIGH-DENSITY 2-DIMENSIONAL ELECTRONGASES IN PSEUDOMORPHIC MODULATION-DOPED QUANTUM-WELLS

We present photoluminescence studies on highly dense two-dimensional e lectron gases in selectively Si delta-doped GaAs/In0.18Ga0.82As/Al0.25 Ga0.75As quantum wells (N(s) = 4.24 x 10(12) cm-2). Five well-resolved photoluminescence lines centered at 1.4194, 1.4506, 1.4609, 1.4695 an d 1.4808 eV were observed, which are attributed to the subband excitio n emission. The subband separations clearly exhibit the feature of a t ypical quantum well with triangle and square potential. These very int ensive and sharp luminescence peaks with linewidths of 2.2 to 3.5 meV indicate the high quality of the structures. Their dependence on the e xcitation intensity and temperatures are also discussed.