Scanning near-field luminescence microscopy of green light emitting GaInN/GaN quantum wells grown on c-plane sapphire and on c-plane bulk GaN

In contrast to blue and violet emitting GaInN quantum well structures grown on sapphire, which show a high internal quantum efficiency (IQE), green emitting structures suffer from relatively low efficiencies. Usually, the large internal polarization fields are made responsible for such reduced efficiencies. For quantum wells with high In content, however, the efficiencies are even lower than expected. In this work we present the results of our near-field optical investigations of the photoluminescence of green emitting GaInN quantum well structures grown on c-plane sapphire and on bulk GaN substrates. Our aim is to clarify the influence of defects on the spatial structure of the luminescence of green emitting quantum wells. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)