Photoluminescence excitation spectroscopy of remotely doped wide parabolic GaAs/${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As quantum wells

Photoluminescence excitation (PLE) spectroscopy was performed on an undoped and several remotely doped wide parabolic GaAs/${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As wells of various well widths and electron sheet densities. For an undoped parabolic well of width 4640 Å, the PLE peak energies are consistent with calculated energies of allowed exciton transitions. The spectra for a remotely doped well of the same width are dominated by a series of uniformly spaced peaks with spacing (∼3.1 meV) approximately equal to the harmonic-oscillator spacing of the bare parabolic conduction-band-edge curvature. Measurements of the dependence of the peak spacing on well width and electron sheet density are presented.