Origins of Light Emission and Efficiency Saturation of the Photoluminescence of GaN Nanocrystallites


The photoluminescence (PL) properties of GaN nanorods were studied utilizing UV micro-photoluminescence. The room temperature PL of the GaN nanorods exhibits one strong emission line. The PL intensity as a function of the laser power was investigated in order to determine whether this emission originates from an excitonic or a bandgap recombination process. Our analysis indicates that the PL of the rods is excitonic-like and very similar to the behavior of the free exciton A in GaN thin films. However, for a relatively large and compact ensemble of rods, the PL intensity exhibits a significant saturation occurring already at relatively low laser power. We attribute the intensity saturation to the laser heating and heat trapping which takes place in the enclosure of the ensemble.

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Leah Bergman gratefully acknowledges NSF CAREER DMR-0238845, NSF-EPS-0132626. Andrew Purdy gratefully acknowledges the Office of Naval Research.

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Correspondence to Xiang-Bai Chen.

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Chen, XB., Morrison, J.L., Penner, M.K. et al. Origins of Light Emission and Efficiency Saturation of the Photoluminescence of GaN Nanocrystallites. MRS Online Proceedings Library 798, 659–664 (2003).

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