Carbon defects as sources of the green and yellow luminescence bands in undoped GaN

By Michael A. Reshchikov, D. Demchenko, A. Usikov, H. Helava, Y. Makarov. 2014

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In high-purity GaN grown by hydride vapor phase epitaxy, the commonly observed yellow luminescence (YL) band gives way to a green luminescence (GL) band at high excitation intensity. We propose that the GL band with a maximum at 2.4 eV is caused by transitions of electrons from the conduction band to the 0 / + level of the isolated C N defect. The YL band, related to transitions via the − / 0 level of the same defect, has a maximum at 2.1 eV and can be observed only for some high-purity samples. However, in less pure GaN samples, where no GL band is observed, another YL band with a maximum at 2.2 eV dominates the photoluminescence spectrum. The latter is attributed to the C N O N complex.

Subfields: Condensed Matter Physics, Electronic, Optical and Magnetic Materials, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/c8fb8ca258d280864413d1eacf56e3e18879f659