Raman scattering study of amorphous Si-Ge interfaces

We have used amorphous superlattice structures to increase the vibrational Raman scattering signal from interfaces between a-Si:H and a-Ge:H. By modeling the Raman spectrum of superlattices as the linear superposition of a-Si:H, a-Ge:H, and a-${\mathrm{Si}}_{0.55}$${\mathrm{Ge}}_{0.45}$:H spectra we have shown that the interface between as-grown a-Si:H and a-Ge:H prepared by plasma-assisted chemical vapor deposition consists of ∼1 monolayer of randomly mixed Si and Ge bounded by pure materials.