Surface roughness is one of the critical parameters affecting solar module efficiency. These surfaces are often intentionally roughened during the deposition process, as an optimally textured surface will absorb more solar radiation than a perfectly smooth one. kSA BandiT PV can get a relative measure of roughness by looking at the “above-gap” scatter from the surface. In theory, any light that has a wavelength sufficiently above the band gap energy should be completely absorbed by the semiconductor layer(s). The amount of scatter is a direct indication of the relative roughness of the surface. We therefore can sum the “above-gap” intensity to determine a relative roughness metric. This metric may also be calibrated directly against a sample of known surface roughness, providing a real-time, in situ quantitative roughness parameter.