Photoluminescence of heterostructures containing an In$_x$Ga$_{1-x}$As quantum well with a high in content at different excitation powers

The results of studies of the photoluminescence spectra of heterostructures containing an In$_x$Ga$_{1-x}$As quantum well with a high In content $x$ at different laser-radiation powers are reported. It is found that, as the radiation power density is increased, the luminescence spectrum of In$_{0.70}$Al$_{0.30}$As/In$_{0.76}$Ga$_{0.24}$As quantum-well heterostructures exhibits a decrease in the half-width and a shift of the peak to higher energies. It is shown that, for Al$_{0.27}$Ga$_{0.73}$As/In$_{0.20}$Ga$_{0.80}$As quantum-well heterostructures, no shift of the peak and no change in the shape of the spectrum is observed. It is established that the integrated photoluminescence intensity is related to the laser-radiation power density by a power law with the exponent $\alpha\approx$ 1.3 for heterostructures with $x\approx$ 0.76, suggesting the predominantly excitonic character of the radiative recombination of charge carriers.