A linear calibration method for scattering semiconductors using the Kubelka-Munk function

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Absorption spectroscopy of solids is hindered by strong scattering, which violates assumptions underlying the Beer-Lambert (BL) law. Although calibration approaches have been reported for scattering solids, their mechanistic basis in terms of the absorption and scattering coefficients remains unclear, and their applicability to semiconductors has not been well documented. Here, we measured ultraviolet-visible diffuse reflectance spectra for nine inorganic semiconductors. From reflectance, we calculated pseudo-absorbance and the Kubelka-Munk function (KMF). The results show that absorbance departs from BL linearity but is well described by an expression derived from KMF with mixture additivity of the coefficients. In contrast, KMF increases linearly with mass fraction within a low-loading regime, and the relation persists across distinct morphologies. Compositions of mixtures recovered from KMF agree closely with preparation values. This work underscores a simple, rapid, and non-destructive calibration strategy for scattering semiconductors that uses KMF as a linear axis for composition.