Optical absorption and exciton linewidths of ${\mathrm{Zn}}_{1\mathrm{-}\mathit{x}}$${\mathrm{Cd}}_{\mathit{x}}$Se quantum wells

Comparison of experimentally determined optical spectra of ${\mathrm{Zn}}_{1\mathrm{-}\mathit{x}}$${\mathrm{Cd}}_{\mathit{x}}$Se/ZnSe quantum wells with theoretical results for fundamental optical absorption and exciton linewidths is used to determine valence-band offset and properties of exciton features as a function of well width and temperature. The heavy-hole valence-band offset is found to be approximately 90 meV for x=0.23. The exciton linewidths are analyzed in terms of Gaussian inhomogeneous broadening attributable to expected sample inhomogeneities involving well widths and alloy concentrations and homogeneous broadening associated with exciton-optical-phonon interactions. The linewidths are found to be smaller and larger than the bulk value for narrow (30 Å) and wide (200 Å) widths, respectively, in agreement with experimental results.