Electron Energy-Loss Spectra of ZnS, ZnSe, and ZnTe

A study has been made of the electron energy-loss spectra of the three $\mathrm{II}B-\mathrm{VI}A$ compounds ZnS, ZnSe, and ZnTe. These spectra have been obtained both by electron-reflection and electron-transmission techniques. The electron-reflection measurements were made from freshly cleaved single-crystal surfaces of all three compounds in an ultrahigh-vacuum atmosphere. Changes in these spectra were observed as the surface was slowly contaminated. The electron-transmission measurements were made only on ZnTe using flash-evaporated thin films. The quality of these films was established by means of x-ray-diffraction, optical-reflectivity, and optical-absorption measurements. The peaks observed in these spectra have been interpreted in terms of interband transitions, surface plasmons, and bulk plasmons. The results are compared with optical-reflectivity measurements and x-ray-induced electron-emission measurements.