Abstract
We report temperature dependent measurements of the Raman spectra of microcrystalline free-standing films. The measurements were performed under direct laser heating of the thin films for temperatures up to 1700 K. The temperature dependence of the TO- and LO-phonon frequencies agrees well with that of single-crystal but the Raman lines are considerably broader. We discuss the influence of stacking faults on the linewidth by comparing our results with computer simulated Raman intensity profiles of structures having randomly distributed stacking faults. Good agreement with respect to the linewidth and disorder-induced peak shift is found if the average stacking fault distance is assumed to be 6 Å. We observe an irreversible narrowing of the Raman lines at temperatures above 1900 K, which we ascribe to an annealing of stacking faults in
- Received 29 May 1998
DOI:https://doi.org/10.1103/PhysRevB.58.9858
©1998 American Physical Society