Abstract
InN films with electron concentration ranging from n∼1017 to 1020 cm−3 grown by metal–organic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE) were investigated by variable-temperature photoluminescence and absorption measurements. The energy positions of absorption edge as well as photoluminescence peak of these InN samples with electron concentration above 1018 cm−3 show a distinct S-shape temperature dependence. With a model of potential fluctuations caused by electron-impurity interactions, the behavior can be quantitatively explained in terms of exciton freeze-out in local potential minima at sufficiently low temperatures, followed by thermal redistribution of the localized excitons when the band gap shrinks with increasing temperature. The exciton localization energy σ loc is found to follow the n 5/12 power relation, which testifies to the observed strong localization effects in InN with high electron concentrations.
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Liu, B., Zhang, Z., Zhang, R. et al. Electron concentration dependence of exciton localization and freeze-out at local potential fluctuations in InN films. Appl. Phys. A 99, 139–143 (2010). https://doi.org/10.1007/s00339-010-5594-3
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DOI: https://doi.org/10.1007/s00339-010-5594-3