Differential Reflection Spectra of Heavily Doped Silicon and Germanium in the Ultraviolet Spectral Region

The effect of heavy doping on the reflection spectra of silicon and germanium is investigated by measuring the fractional change in reflectance, ΔR/R, between pure and doped materials. This effect arises from the narrowing of the forbidden gap in heavily doped materials. The form of the ΔR/R spectrum allows to reveal the critical points of the band structure, as in electro-, piezo-, or thermoreflectance measurements. [Russian Text Ignored].