H. Selke et al., Compositional inhomogeneities in InGaN studied by transmission electron microscopy and spatially resolved cathodoluminescence, MAT SCI E B, 59(1-3), 1999, pp. 279-282
The structural and optical properties of InGaN epilayers grown by different
molecular beam epitaxy (MBE) techniques were studied with high spatial res
olution. Mappings of the local emission wavelength obtained by cathodolumin
escence (CL) spectroscopy indicate lateral and spectral inhomogeneities in
the luminescence of InGaN epilayers grown with continuous In and Ga fluxes.
These results agree well with variations in the chemical composition in th
e lateral and in the growth direction seen in mappings of the local composi
tion which were obtained by energy-dispersive X-ray (EDX) microanalysis in
cross-sectional transmission electron microscopy (TEM). Possible origins of
these variations are discussed. In comparison, epilayers grown with altern
ating deposition of (In, Ga)N and (Ga)N are more homogeneous. (C) 1999 Else
vier Science S.A. All rights reserved.