Near-field cathodoluminescence studies on n-doped gallium nitride films



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Nogales Díaz, Emilio and Joachimsthaler, I. and Heiderhoff, R. and Piqueras de Noriega, Javier and Balk, L.J. (2002) Near-field cathodoluminescence studies on n-doped gallium nitride films. Journal of Applied Physics, 92 (2). pp. 976-978. ISSN 0021-8979

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Near-field cathodoluminescence (NFCL) has been used to characterize hydride vapor phase epitaxy grown n-GaN films. This technique can obtain high resolution luminescence images and perform local measurements of the diffusion length for minority carriers in different parts of the sample. NFCL contrast observed in round growth hillocks at the sample surface, with a diameter of less than 10 mum, is compared with that observed by conventional cathodoluminescence in scanning electron microscope (CLSEM) techniques. In particular NFCL images reveal features not detected by CLSEM which is explained by the fact that under near field conditions the signal arises from a depth of only several tens of nanometers and is then directly related to the surface hillocks. Diffusion lengths of about 0.4 and 4 mum have been found for the holes in different regions of the samples at room temperature. The order of magnitude of these minority carriers diffusion lengths is in good agreement with previous measurements performed at different GaN samples with other techniques. The NFCL contrast and the differences in the measured diffusion lengths are discussed and explained by variations in local trap concentrations.

Item Type:Article
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© 2002 American Institute of Physics.
This work was supported by MCYT /Project MAT2000-2119).

Uncontrolled Keywords:Gan Epilayers, Luminescence, Defects
Subjects:Sciences > Physics > Materials
ID Code:26282
Deposited On:17 Jul 2014 11:29
Last Modified:17 Jul 2014 11:29

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