Polarized Raman scattering studies of nonpolara-plane GaN films grown onr-plane sapphire substrates by MOCVD

✍ Scribed by Gao, Haiyong ;Yan, Fawang ;Li, Jinmin ;Wang, Junxi ;Yan, Jianchang

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 270 KB
• Volume: 203
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/pssa.200622306

✦ Synopsis

Abstract

Nonpolar (11$ \bar 2 $0) a ‐plane GaN thin films were grown on r ‐plane (1$ \bar 1 $02) sapphire substrates by low‐pressure metal organic chemical vapor deposition (MOCVD). The stress characteristics of the a ‐plane GaN films were investigated by means of polarized Raman scattering spectra in backscattering configurations. The experimental results show that there are strong anisotropic in‐plane stresses within the epitaxial a ‐plane GaN films by calculating the corresponding stress tensors. The temperature dependence of Raman scattering spectra was studied in the range from 100 K to 550 K. The measurements reveal that the Raman phonon frequencies decrease with increasing temperature. The temperature at which nonpolar a ‐plane GaN films are strain free is discussed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)