Characterization of MBE-grown Ga1−xAlxAs alloy films by Raman scattering

✍ Scribed by Hou, Y. T.; Feng, Z. C.; Li, M. F.; Chua, S. J.

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 94 KB
• Volume: 28
• Category: Article
• ISSN: 0142-2421
• DOI: 10.1002/(sici)1096-9918(199908)28:1<163::aid-sia598>3.0.co;2-i

✦ Synopsis

Molecular beam epitaxy (MBE)-grown ternary Ga 1-x Al

x As films, with Al composition x ranging from 0 to 1 in steps of 0.1, have been studied by Raman scattering at room temperature and at 80 K. The observed broadening and asymmetry of the first-order longitudinal-optical phonon spectra induced by alloy disorder are simulated using the spatial correlation model. The obtained correlation length for GaAs-like and AlAs-like modes are observed to decrease as the reduction of Ga composition 1 -x and Al composition x , respectively. It is also shown that the correlation length depends sensitively on the composition. No significant temperature or phonon mode dependence is found. A combination with thermodynamic analysis suggests that the random compositional distribution in alloy seems to be the dominant contribution to this disorder effect.