Optical characterization of lateral epitaxial overgrown GaN layers

• Published in: Applied physics letters 1998-06, Vol.72 (23), p.2990-2992
• Main Authors: Freitas, Jaime A., Nam, Ok-Hyun, Davis, Robert F., Saparin, Gennady V., Obyden, Sergey K.
• Format: Article
• Language: English
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.121517

The optical properties of homoepitaxial GaN layers deposited by organometallic vapor phase epitaxy on stripe-patterned GaN films on 6H-SiC substrates have been investigated. Analysis of the spatially-resolved Raman scattering spectra indicate an improvement in material quality of the overgrown region. Room-temperature color cathodoluminescence imaging and low-temperature photoluminescence measurements indicate that a donor and an acceptor, different from those detected in the underlying GaN/AlN/SiC substrate, have been incorporated in the epitaxial layer. Detailed photoluminescence studies of the near-band-edge emission strongly suggest that Si is the additional donor detected in the homoepitaxial GaN layer. Its occurrence, along with that of an acceptor-related defect which is primarily found in the laterally overgrown region, is discussed.