High-pressure studies of GaAs-Ga1-xAlxAs quantum wells of widths 26 to 150 Å

Abstract

Photoluminescence spectra of GaAs quantum wells of widths 26 to 150 Å are studied as a function of hydrostatic pressure (0-70 kbar) at 80 and 150 K. The pressure coefficients of both the heavy- and light-hole excitons are found to decrease with decreasing well width. The direct to indirect conduction-band crossover, leading to the formation of type-II heterostructures, occurs at higher pressures for wider wells. A transition associated with the X conduction band in quantum-well structures is observed and its pressure dependence is established. Correlating this transition to barrier-to-well recombination determines the valence-band offset.