Effect of V/III ratio on the growth of (112¯2) AlGaN by metalorganic vapour phase epitaxy
Autor: | Duc V. Dinh, Peter J. Parbrook, Shahab N. Alam |
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Rok vydání: | 2016 |
Předmět: |
010302 applied physics
Low temperature photoluminescence Morphology (linguistics) Materials science business.industry Exciton Analytical chemistry Dangling bond chemistry.chemical_element 02 engineering and technology 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Nitrogen Inorganic Chemistry Wavelength chemistry 0103 physical sciences Materials Chemistry Sapphire Optoelectronics Metalorganic vapour phase epitaxy 0210 nano-technology business |
Zdroj: | Journal of Crystal Growth. 435:12-18 |
ISSN: | 0022-0248 |
Popis: | 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 [ 1 1 ¯ 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 29.5−47.9%, which is lower than the composition of the simultaneously grown (0001) reference layers (30.4−58.0%). 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 60−194 meV, and this shift increases with increasing Al-content (decreasing V/III ratio) correlated to an increased exciton localization. |
Databáze: | OpenAIRE |
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