TEMPERATURE-DEPENDENCE OF THE PHOTOREFLECTANCE OF A STRAINED LAYER (001) IN0.21GA0.79AS/GAAS SINGLE QUANTUM-WELL

We have measured the photoreflectance spectra of a strained layer (001) In0.21Ga0.79As/GaAs single quantum well as a function of temperature in the range 10 K < T < 500 K. The details of the line shape of the fundamental conduction to heavy-hole feature (11H) demonstrates its excitonic nature even up to 500 K. From the temperature dependence of the 11H linewidth we have obtained important information about the quality of the material and interface. The variation of the 11H energy gap with temperature agrees with that of bulk material. Comparison of the energies of 11H and higher lying transitions with an envelope function calculation yields a conduction band offset parameter Q(c) = 0.65 +/- 0.07.