Zhou K.,CAS Institute of Semiconductors |
Zhou K.,CAS Suzhou Institute of Nano Technology and Nano Bionics |
Zhou K.,Key Laboratory of Nanodevices and Applications |
Liu J.,CAS Suzhou Institute of Nano Technology and Nano Bionics |
And 12 more authors.
Journal of Crystal Growth | Year: 2015
Surface morphology of homoepitaxial GaN (0001) grown by metalorganic vapor phase epitaxy was studied. Selective growth was observed on the homoepitaxial GaN layer grown on as-received GaN substrate and was attributed to the existence of substrate surface defects. The steps were pinned by defects and meandered. Due to the pinning effect, the step pattern developed to a wavy surface with a strip-like feature along the [112¯0] direction during the subsequent growth of a thick n-GaN layer. Because of the surface undulations, the emission of InGaN/GaN multiple quantum wells grown on the n-GaN layer was inhomogeneous. The surface defects on GaN substrate could be removed by dry etching and the homoepitaxial layer on the etched substrate showed a smooth morphology and straight atomic steps. As a result, the emission of the InGaN/GaN MQWs became homogeneous. © 2015 Elsevier B.V. All rights reserved.