Optical energies of AllnN epilayers

Wang, K. and Martin, R. W. and Amabile, D. and Edwards, P. R. and Hernandez, S. and Nogales, E. and O'Donnell, K. P. and Lorenz, K. and Alves, E. and Matias, V. and Vantomme, A. and Wolverson, D. and Watson, I. M. (2008) Optical energies of AllnN epilayers. Journal of Applied Physics, 103 (7). 073510. ISSN 0021-8979

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    Abstract

    Optical energy gaps are measured for high-quality Al1−xInxN-on-GaN epilayers with a range of compositions around the lattice match point using photoluminescence and photoluminescence excitation spectroscopy. These data are combined with structural data to determine the compositional dependence of emission and absorption energies. The trend indicates a very large bowing parameter of 6 eV and differences with earlier reports are discussed. Very large Stokes' shifts of 0.4-0.8 eV are observed in the composition range 0.13<x<0.24, increasing approximately linearly with InN fraction despite the change of sign of the piezoelectric field