Temperature dependence of photoluminescence and photoreflectance spectra of dilute GaAsN alloys -: art. no. 121918

The temperature dependence of photoluminescence (PL) and photoreflectance (PR) spectra of GaAs1-xNx unrelaxed layers (0 <= x < 0.05) grown on GaAs (100) substrates is studied and compared. The energy gap deduced from PR measurements and its temperature dependence are in good agreement with predictions of the band anticrossing model. The main PL peak follows a different temperature dependence, being lower in energy than the energy gap obtained by PR. The observed energy difference between PR and PL is much larger than the typical exciton binding energy, increasing with N content. This result agrees with other works, suggesting that low temperature PL recombination in GaAs1-xNx involves electrons trapped in potential fluctuations due to N concentration inhomogeneities. (C) 2005 American Institute of Physics.