Temperature dependence of the PL intensity of ordered and disordered In0.48Ga0.52P.

The integrated photoluminescence (PL) intensities of both ordered and disordered epilayers of InGaP grown on GaAs have been measured as a function of temperature. The highest PL efficiency occurs in the most disordered sample. We find that the PL intensities can drop from 2 to almost 4 orders of magnitude between 12 and 280 K. The samples show an Arrhenius behavior characterized by two activation energies. Below 100 K the activation energies lie in the region of 10-20 meV. Above 100 K the activation energy is approximately 50 meV except in the most disordered sample where it increases to 260 meV We conclude that the low-temperature PL efficiency is most likely controlled by carrier thermalization from spatial fluctuations of the band edges followed by nonradiative recombination. At higher temperatures the PL efficiency is dominated by a nonradiative path whose characteristic activation energy and transition probability depend upon the degree of sublattice ordering.