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.
The photoluminescence (PL) of an Ino 486ap 52P/(Ala 26ao 8 )p 52Inp 48P multiple-quantum-well sample composed of wells of various widths has been measured as a function of temperature. The presence of LO-phonon replicas at low temperature for the largest well indicates that the PL is dominated by localized excitons. This is further con6rmed by the variation of the PL peak energies and PL linewidths as the temperature is increased above 4.2 K. The temperature dependence of the integrated PL intensities shows that the major loss mechanism is thermal activation of electron-hole pairs out of the wells followed by nonradiative recombination in the barriers. The experimental data substantiate the proposition that the poor thermal characteristics of visible lasers is caused by carrier 1eakage out of relatively shallow wells.
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