Investigation of nanoscale composition fluctuations in InGaN using optical transmission spectroscopy and near-field scanning optical microscopy
ABSTRACT Nanoscale composition fluctuations in InGaN alloy epitaxial layers have been investigated by optical transmission spectroscopy and near-field scanning optical microscopy. A spatial variation of the optical transmission at 488 nm is observed, which is attributed to an inhomogeneous indium distribution. Both the characteristic wavelength and the normalized root mean square magnitude of the compositional fluctuations increase with increasing In concentration. The fluctuations are well described in terms of a spinodal decomposition model.