Data for "Compositional dependence of direct transition energies in SiGeSn alloys lattice-matched to Ge/GaAs"

Spectroscopic ellipsometry data (raw data and optical constants extracted from data fitting, and R and Python scripts for analysis and plotting) for SixGe1-x-ySny alloys at six different compositions. Accompanies the paper "Compositional dependence of direct transition energies in SiGeSn alloys lattice-matched to Ge/GaAs" (authors: Phoebe M. Pearce, Sheau Wei Ong, Andrew D. Johnson, Eng Soon Tok, Nicholas J. Ekins-Daukes).