The use of high resolution electron-energy-loss spectroscopy for refining the infrared optical constants of GaS, GaSe, and InSe

Abstract Cleaved surfaces of III–VI lamellar semiconducting compounds GaS, GaSe, and InSe have been studied by high resolution electron-energy-loss spectroscopy (HREELS). The infrared optical constants of the materials were retrieved by using the dielectric theory taking account of the resonance frequencies published from infrared reflectivity (IRS) data. The limitations of the HREELS and IRS measurements in the case of these materials are discussed in detail. However, it is shown that, by combining the informations from both spectroscopies, it is possible to refine some of the oscillator strengths of these materials.