1. A method comprising: receiving a spectral response of an unfinished, multi-layer semiconductor wafer across a first spectral range; determining an optical dispersion metric of a first layer of the multi-layer semiconductor wafer based at least in part on the spectral response by one or more computing systems; determining a band structure characteristic indicative of an electrical performance of the first layer of the multi-layer semiconductor wafer based at least in part on the dispersion metric of the multi-layer semiconductor wafer across a second spectral range within the first spectral range by the one or more computing systems; and determining an estimate of the electrical performance of the multi-layer semiconductor wafer based at least in part on the band structure characteristic by the one or more computing systems.