Spatial variation of luminescence in thick GaN films

F. Bertram, S. Srinivasan, Fernando Ponce, T. Riemann, J. Christen, R. J. Molnar

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Abstract

The spatial variation of the optical properties of hydride vapor-phase epitaxial GaN layers of various thickness has been studied using scanning cathodoluminescence microscopy. A strong improvement of these properties with film thickness is observed in plan view. Cross-sectional studies show a strong redshift of the luminescence in the vicinity of the substrate within a typical thickness of about 2 μm, reflecting a high local impurity content. Above this initial growth region, a strong blueshift is observed up to the energy of fully relaxed high-purity GaN, indicating vertical strain relaxation as well as depletion of residual donors. This is accompanied by a sharp increase in the lateral spectral homogeneity, indicative of a significant improvement in crystalline quality.

Original languageEnglish (US)
Pages (from-to)1222-1224
Number of pages3
JournalApplied Physics Letters
Volume78
Issue number9
DOIs
StatePublished - Feb 26 2001

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ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

Cite this

Bertram, F., Srinivasan, S., Ponce, F., Riemann, T., Christen, J., & Molnar, R. J. (2001). Spatial variation of luminescence in thick GaN films. Applied Physics Letters, 78(9), 1222-1224. https://doi.org/10.1063/1.1350594