Xu, S. J.Wang, H. J.Cheung, S. H.Li, Q.Dai, X. Q.Xie, M. H.Tong, S. Y.2015-12-032015-12-030003-6951http://hdl.handle.net/1885/16991A number of wurtzite GaN epilayers directly grown on 4H-SiC-(0001) misoriented by 0, 3.5°, 5°, 8°, and 21° with plasma-assisted molecular-beam epitaxy were optically characterized with photoluminescence and excitation spectra. An intense shallow-defect emission peak locating at energy position ~70 meV lower than the near band edge emission peak at 3.47 eV is found in the emission spectra of the GaN films on 4H-SiC misoriented by 8° and 21°. Stacking mismatch boundaries are supposed to be the candidate causing the optical transition. Combined with the low-temperature photoluminescence excitation spectra of the films, the location of the electronic level induced by the structural defect is determined to be about 100 meV above the valence-band maximum of GaN.The work was supported by HK-RGC CERG Grant ~No. HKU 7036/03P! and partly supported by NSFC/RGC Joint Research Scheme ~N–HKU028/ 00).3 pages© 2003 American Institute of Physics Publishing. This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. The following article appeared in Applied Physics Letters and may be found at http://doi.org/10.1063/1.1623006 http://publishing.aip.org/authors/copyright-reuse http://www.sherpa.ac.uk/romeo/issn/0003-6951 Author can archive publisher's version/PDF (Sherpa/Romeo as of 3/12/2015).wurtzite GaN epilayers4H-SiC ~0001misoriented by 0, 3.5°, 5°, 8°, and 21°plasma-assisted molecular-beam epitaxyphotoluminescenceexcitation spectra2003-10-2710.1063/1.1623006