A comparative study of ordered alloy and random alloy quantum wells of Zn_{1 - x}Cd_xSe ZnSe under pressure

Excitonic transitions in random alloy and ordered alloy quantum wells of Zn_{1 - x}Cd_xSe ZnSe are studied as a function of hydrostatic pressure at 14 K using photoluminescence. A sample of bulk Zn_{1 - x}Cd_xSe is also studied in the same pressure loading as the other two samples to determine the increase in the bandgap as a function of pressure. This simultaneous study has allowed us to isolate the pressure-induced changes due to quantization effects, as well as to study the differences between the random and ordered alloy quantum well systems. We find that the influence of ordering in these samples is evident at thicknesses of ~ 25 Å and less. We also find that a single period of the ordered alloy behaves like a quantum well, despite a large overlap of the wavefunction with the barrier and an extremely large confinement energy.