Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8149455 | Journal of Crystal Growth | 2016 | 7 Pages |
Abstract
The effect of V/III ratio on the growth and properties of AlGaN layers grown on (112¯2) AlN templates grown on (101¯0) sapphire by metalorganic vapour phase epitaxy was studied. The surface morphology of the (112¯2) AlGaN layers and the (112¯2) AlN templates showed an undulation along [11¯00]AlGaN,AlN. The Al-content and thickness of the layers increased with decreasing V/III ratio due to a reduction in the parasitic reactions of the precursors. The Al-content of the (112¯2) layers was found to be in the range of 29.5â47.9%, which is lower than the composition of the simultaneously grown (0001) reference layers (30.4â58.0%). This was attributed to a higher density of cation (nitrogen) dangling bonds on the (112¯2) surface. Low temperature photoluminescence measurements of the (112¯2) layers showed an emission wavelength that shifts gradually from 273 nm to 306 nm with increasing V/III ratio. A decreased PL intensity of the layers with decreasing V/III ratio was attributed to an increase in cation vacancies. The Stokes-shift of the (112¯2) layers was estimated to be about 60â194 meV, and this shift increases with increasing Al-content (decreasing V/III ratio) correlated to an increased exciton localization.
Keywords
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Condensed Matter Physics
Authors
Duc V. Dinh, S.N. Alam, P.J. Parbrook,