Spectroscopic ellipsometry (SE) studies on vacuum-evaporated ZnSe thin films

Iodine-doped ZnSe thin films were prepared onto well-cleaned glass substrates using vacuum evaporation technique under a vacuum of 3.4 × 10− 3 Pa. The composition, structural, optical and electrical properties of the deposited films were analyzed using Rutherford Backscattered Spectrometry (RBS), X-ray diffraction (XRD), spectroscopic ellipsometry (SE) and I–V characteristics. In the RBS analysis, the composition of the deposited film was calculated as (ZnSe)I0.003. The structure of the deposited film was identified as cubic, oriented along the (111) direction. The structural parameters such as particle size, strain and dislocation density values were calculated as 28.28 nm, 1.38 × 10− 3 lin− 2 m− 4 and 1.29 × 1015 lin/m2, respectively. Spectroscopic Ellipsometric (SE) measurements were done on the (ZnSe)I0.003 thin films. The spectral data showed three distinct critical-point structures, including weak structures at E0 + Δ0, indicating that the sample has a high crystalline quality. The optical band gap value of the deposited films was calculated as 2.63 eV using optical transmittance measurements. From the I–V characteristics studies, the conduction mechanism was found to be SCLC.