Heteroepitaxy of AlGaN on bulk AlN substrates for deep ultraviolet light emitting diodes

The authors report the growth of AlGaN epilayers and deep ultraviolet (UV) light emitting diodes (LEDs) on bulk AlN substrates. Heteroepitaxial nucleation and strain relaxation are studied through controlled growth interruptions. Due to a low density of preexisting dislocations in bulk AlN, the comp...

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Bibliographic Details
Published in:Applied physics letters 2007-07, Vol.91 (5), p.051116-051116-3
Main Authors: Ren, Z., Sun, Q., Kwon, S.-Y., Han, J., Davitt, K., Song, Y. K., Nurmikko, A. V., Cho, H.-K., Liu, W., Smart, J. A., Schowalter, L. J.
Format: Article
Language:English
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Summary:The authors report the growth of AlGaN epilayers and deep ultraviolet (UV) light emitting diodes (LEDs) on bulk AlN substrates. Heteroepitaxial nucleation and strain relaxation are studied through controlled growth interruptions. Due to a low density of preexisting dislocations in bulk AlN, the compressive strain during AlGaN heteroepitaxy cannot be relieved effectively. The built-up of strain energy eventually induces either an elastic surface roughening or plastic deformation via generation and inclination of dislocations, depending on the stressor interlayers and growth parameters used. AlGaN LEDs on bulk AlN exhibit noticeable improvements in performance over those on sapphire, pointing to a promising substrate platform for III-nitride UV optoelectronics.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.2766841