Photoluminescence of short-period GaAs/AlAs superlattices: A hydrostatic pressure and temperature study

Abstract

The temperature and pressure dependence of type-I and -II transitions from photoluminescence (PL) spectra in a series of $(\mathrm{GaAs}{)}_m/(\mathrm{AlAs}{)}_m$ superlattices show that the temperature dependence of energy bands can be described very well with a Bose-Einstein-type equation. From these measurements the parameters that describe the temperature dependence of excitonic transition energies and the corresponding broadening of the PL line are deduced. The pressure dependence of the PL linewidths of the type-I exciton as a function of pressure and temperature yield the intervalley deformation potential. Beyond the type-I–type-II crossover, the PL linewidth increases as a function of both pressure and temperature. The electron-phonon deformation potential for $\Gamma -X$ scattering is found to be temperature dependent.