Nanoscale physics

Optical-energy properties of CdSe thin film
Ilchuk H.A.1, Petrus R.Yu.1, Kashuba A.I.1,2, Semkiv I.V.1, Zmiiovska E.O.1
1 Lviv Polytechnic National University, 12, S. Bandera Str., Lviv-79013, Ukraine.
E-mail: AndriyKashuba07@gmail.com
2 Ivan Franko National University of Lviv, 107, Tarnavsky Str., Lviv-79005, Ukraine.

CdSe thin films were obtained by close‐spaced sublimation (CSS) at pressure 1·10-6 Torr. The source and substrate material temperature was 900 K and 700 K, respectively. The temperature was controlled using the PID-regulator of temperature PE-202 using a thermocouple of the type "K". The relative error of temperature didn’t exceed 0.2 %. The substrates were 14 mm in diameter were used for deposition CdSe thin films. Before the CdSe film deposition, the substrate surface was cleaned by boiling in a high purity CCl4 solution during 0.25 h.
The phase analysis and crystal structure refinement was examined with using X-ray powder diffraction data on a STOE STADI P diffractometer at the room temperature. Morphology of the samples was examined using REMMA- 102- 02 Scanning Electron Microscope-Analyzer (JCS SELMI, Ukraine). The optical transmission was measured using a spectrophotometer Shimadzu UV-3600.
The theoretical calculations were made using the electron density functional theory (DFT) successfully applied to studying single-crystal samples [1]. Based on the crystal structure of bulk crystal CdSe was built the thin film (~ 10 nm thickness) in the crystallographic a-axis. For ionic potentials, the ultrasoft Vanderbilt pseudo-potentials were used [2]. To describe the exchange-correlation energy of the electron subsystem, the GGA functional with the PBE parameterization [3] was used.
As a result, we present the theoretical and experimental studies of structure, surface and the optical properties at room temperature of CdSe thin film.

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