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Identification of a Cubic Phase in Epitaxial Layers of Predominantly Hexagonal GaN

1996; Cambridge University Press; Volume: 1; Linguagem: Inglês

10.1557/s1092578300002167

1092-5783

Uwe Strauß, H. Tews, H. Riechert, R. Averbeck, M. Schienle, B. Jobst, D. Volm, T. Streibl, B. K. Meyer, W. W. Rühle,

Ga2O3 and related materials

Epitaxial layers of GaN on c-plane sapphire are analyzed by continuous-wave and time-resolved photoluminescence at 4K and by X-ray diffraction. Besides the well-known emissions from hexagonal GaN we observe luminescence bands at 3.279 and 3.15 to 3.21 eV which are identified as the transition of the donor bound exciton and the donor-acceptor pair recombination in cubic GaN, respectively. Measurements of the luminescence decay times are essential for the clarification of the emission processes. Due to the probing depth of about 200 nm in PL we find that the fraction of cubic phase typically decreases with layer thickness. In our best samples, however, we do not detect the cubic phase at all.