Investigation of optical parameters of thermally evaporated ZnSe thin films

In this work, zinc selenide (ZnSe) thin films were deposited by thermal evaporation method using pure elemental (Zn and Se) sources. The physical properties of the films have been investigated in terms of the structural and optical characterizations depending on the post-annealing process under nitrogen atmosphere in the temperature between 300 and 500 °C for 30 min. The structural and compositional analyses were carried out by means of X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS). The compositional ana- lysis indicated that the deposited films were nearly stoichiometric whereas there was a decrease in Se and increase in the Zn contents. This implies the segregation and/or re-evaporation of Se atoms from the thin film structure. The optical characteristics were studied by using the room temperature transmission measurements. The analysis of transmission values showed that the band gap values changed in between 2.38 and 2.62 eV depending on the annealing temperatures. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)