Raman scattering and optical absorption measurements have been used to study the structural and electronic properties of a-Sil-xHx films made by homogeneous chemical vapor deposition. The Raman spectra show that the hydrogenated films are more ordered than pure a-Si films. For x ≲0.04 the optical gap E0 correlates with ΔVH-1, the structural order parameter. At higher hydrogen concentrations, however, ΔVH-1 is relatively constant and E0 increases due to alloy rather than structural ordering effects. © 1983.