A study was made of the photoluminescence emitted by a heterostructure
with a single quantum well in the GaAs-In0.15Ga0.85As system at high
excitation rates (up to 10(6) W/cm2) and high photocarrier densities (
approximately 10(14) cm-2). Occupancy of quantum well states by photoc
arriers under these conditions gave rise to singularities in the photo
luminescence spectrum at energies corresponding to optical transitions
between several quantum-size subbands.