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论文类型：期刊论文
发表时间：2013-09-01
发表刊物：JOURNAL OF TESTING AND EVALUATION
收录刊物：SCIE、Scopus
卷号：41
期号：5
页面范围：798-803
ISSN号：0090-3973
关键字：GaN; metalorganic chemical vapor deposition; stress state; dislocations
摘要：The stress states and influence of two opposite stress types under similar stress intensities on the structural and optical properties of GaN films grown on sapphire and 6H-SiC substrates via metalorganic chemical vapor deposition were investigated. The E-2 (high) phonon shifts of Raman spectra show that tensile stresses exist in the GaN epilayer grown on 6H-SiC, whereas compressive stresses appear in the film grown on sapphire, indicating that the thermal mismatch between the epilayers and the substrates plays a major role in determining the residual stresses in GaN films. Narrower full widths at half-maximum of E2 (high) phonon and double crystal X-ray diffraction peaks and the higher E2 (high) phonon intensity are visible for the GaN film grown on sapphire, illustrating that under almost equivalent stress intensities, tensile stresses have a much more negative influence on the crystalline quality of GaN epilayers. Finally, a numerical relationship between the luminescent band gap and the biaxial stresses of the GaN films is obtained at 10 K.