Physico-Chemical nanomaterials science

Influence of the thickness on optical properties
of CdSe thin films
Kashuba A.I.1, Petrus R.Y.1, Ilchuk H.A.1, Semkiv I.V.1, Andriyevsky B.2, Piasecki M.3, Kashuba N.Y.1, Malyi T.S.4
1Department of General Physic, Lviv Polytechnic National University, 
Bandera Str., 12, Lviv-79046, Ukraine
E-mail: andrii.i.kashuba@lpnu.ua
2Faculty of Electronics and Computer Sciences, Koszalin University of Technology, Sniadeckich Str., 2, Koszalin 75-453, Poland
3Faculty of Science and Technology, Jan Dlugosz University Czestochowa,
Armii Krajowej Al., 13/15, Czestochowa 42-201, Poland
4 Department of Experimental Physics, Ivan Franko National University of Lviv, Kyryla and Mefodiya Str., 8a, Lviv-79005, Ukraine

Cadmium sulfide thin films with different thickness were deposited on quartz substrates by the method of high-frequency magnetron sputtering using a VUP-5M vacuum station (Selmi, Ukraine). Commercial target of 99.99 % purity was used for deposition. The target–substrate distance was equal to 60 mm. The start and end of the sputtering process were controlled by means of a movable shutter. The phase analysis and crystal structure refinement was examined with X-ray diffraction data (XRD) obtained on DRON-2.0M diffractometer at room temperature with the Kα radiation (λ= 1.936087 Å) of Fe. The spectral dependence of optical transmittance and reflection of the obtained samples were measured in the visible and near infrared regions (300-1500 nm) at room temperature using the spectrometer Shimadzu UV-3600.
Crystal structure of CdSe thin films has been determined from XRD. Cadmium sulfide thin film crystallizes in hexagonal structure (structure type - ZnO, space group P63mc (No. 186)). No additional peaks (by X-ray analysis) belonging to other phases can be detected, which indicates the formation of a pure single phase of CdSe.
The optical properties of a thin film (refractive index n(λ), absorption coefficient α(λ), extinction coefficient k(λ), dielectric functions ε(λ) and thickness d) can be easily evaluated from a transmission spectrum with interference effects using the envelope method.