The Optical Properties of Thin Single-Crystal CdS Films in a Wide Spectral Interval,

For reflection, absorption, and dispersion measurements, single-crystal CdS thin films of various thickness were used. The thickness of the particular thin film used was determined. Reflection curves were measured by the normal incidence of light on the crystal studied. For the measurements of the absorption and dispersion curves, photographic, photoelectric, and interference methods were used. The curves obtained are discussed in detail, and the measured value compared with calculated values. There is essentially no difference between the surface and the bulk layers of CdS crystals, insofar as the optical properties are concerned. The use of thin single-crystal films makes it possible to measure the spectral distribution of absorption and dispersion in a polarized light in a wide region beyond the absorption limit, corresponding to the excitation of the depth of the conduction band. Based on these data, certain conclusions can be made relative to the intensity and the polarization of structural absorption, which then makes this a convenient and useful method for the study of band structure of crystals. Author