LUMINESCENCE AND INTERSUBBAND EXCITATIONS IN HIGH-DENSITY 2-DIMENSIONAL ELECTRON GASES

We report a detailed analysis of both luminescence and electronic Rama n-scattering results in modulation-doped single quantum wells. Wave-ve ctor nonconservation in the electron-hole recombination process is dem onstrated in these highly doped systems. We also observe, in both pola rizations, surprisingly intense Raman lines in addition to the collect ive excitations of the electron gas. The single-particle character of these lines is proved from the analysis of their dispersion and line s hape as a function of the Raman in-plane wave vector.