Strong interface-induced changes on the numerical calculated Raman scattering in Si/3C-SiC superlattices

Raman spectra of (3C-SiC)(8-delta)/(3C-SiC0.5Si0.5)(delta)/(Si)(8-delta)/(3 C-SiC0.5Si0.5)(delta) superlattices with interfacial transition regions of thickness delta varying from one to three monolayers are calculated. It is shown that severe frequency shifts (up to -86 cm(-1)) and the flattening of the folded optical phonons dispersion curves are due to the interfacial re gions, strongly affecting the Raman spectrum in consequence. With increasin g interface thickness, the Raman peaks are enhanced in the middle frequency range. These effects are mainly attributed to localization of atomic displ acements at the Si/3C-SiC or the 3C-SiC/Si interfacial transition regions. (C) 2000 American Institute of Physics. [S0003- 6951(00)01948-3].