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Comparison of Luminescence and Physical Morphologies of GaN Epilayers
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- Journal:
- Materials Research Society Internet Journal of Nitride Semiconductor Research / Volume 2 / 1997
- Published online by Cambridge University Press:
- 13 June 2014, e31
- Print publication:
- 1997
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In this paper we examine a series of four GaN epilayers grown by MOVPE on sapphire substrates with different AlN buffer layer thicknesses. We examine the effect of the buffer layer thickness on the physical and optical properties of the samples via optical microscopy, cathodoluminescence imaging and photoluminescence and cathodoluminescence spectroscopy. While the morphological and optical properties of all the films (excepting that with the thinnest buffer layer of 30 nm) are good, i.e., the films are smooth and the luminescence is dominated by excitonic luminescence, a number of circular island like features are observed in all the films whose density decrease with increasing buffer layer thickness. A large circular island present on the sample with the thinnest buffer layer and surrounded by cracks in the
directions, displays some interesting acceptor related luminescence.
directions, displays some interesting acceptor related luminescence.