PRESSURE-DEPENDENCE OF THE EXCITON ABSORPTION AND THE ELECTRONIC SUBBAND STRUCTURE OF A GA0.47IN0.53AS AL0.48IN0.52AS MULTIPLE-QUANTUM-WELLSYSTEM/

We have measured the optical absorption of a Ga0.47In0.53As/Al0.48In0. 52As multiple quantum well at 10 K for pressures up to 7 GPa. The ener gies of optical transitions between heavy- and light-hole subbands and electron levels of the wells show a blueshift with pressure similar t o the bulk lowest direct band gap. We observe a decrease with pressure of the energy splitting between heavy- and light-hole subbands with t he same quantum number n. From the analysis of the absorption line sha pe, we have obtained the pressure dependences of exciton binding energ ies, oscillator strengths, and linewidths. These results are interpret ed in terms of subband-structure calculations within the envelope-func tion approximation.