Effect of Doping Concentration of Potassium (K) on the Crystallographic and Optical Properties of Cesium Iodide Films (CsI)

In this work, we study the properties of cesium iodide (CsI) thin film as a function of potassiumdoping concentrations The X-Ray diffraction of cesium iodide shows polycrystalline in nature with centered cubic (bcc) structure. The optical transmittance of cesium iodide films has been analyzed in the spectral range from 200 nm to 800 nm. The optical gapenergy is calculated from the extrapolation of (h) 2 via (h) for direct transitions, the experimental data show the energy gap decrease with increasing doping concentration from3.85 to 3.79eV.