New results on optical, crystallographic and morphological properties of CsI photocathode

Alkali halide materials are of technological importance due to their excellent electron-emitting properties in the ultraviolet (UV), vacuum ultraviolet (VUV), extreme ultraviolet (EUV) and X-ray energy ranges. Among alkali halide photo cathodes, CsI is the best choice, owing to its high quantum efficiency (QE) in the VUV wavelength range. Due to the importance of CsI photocathodes, several thin film preparation methods, such as thermal evaporation, ion beam sputtering, pulsed laser deposition, are used to study the various physical and chemical properties of CsI. However, it has been observed that the thermal evaporation is the best choice forming a stoichiometric Cs: I ratio as well as the highest absolute quantum efficiency (QE) compared to other preparation techniques. In the present work the optical absorbance and transmittance have been investigated by UV-Vis, the structural properties have been studied by XRD and the morphological analysis has been done by AFM