pISSN 0374-4914 eISSN 2289-0041

## Research Paper

New Physics: Sae Mulli 2006; 53: 240-246

Published online September 1, 2006

## The Optical Properties of a Cubic CdS Epilayer Obtained by Using Spectroscopic Ellipsometry

D. J. KIM1*, T. G. KOO2, Y. D. CHOI3

1Institute of Science and Thecnology, Mokwon University, Daejeon 302-729
2Department of Physics, Chungnam National University, Daejeon 305-764
3Department of Optical & Electronic Physics, Mokwon University, Daejeon 302-729

Correspondence to:djkim@mokwon.ac.kr

### Abstract

Cubic CdS epilayers were grown on GaAs(100) substrates by using a hot-wall epitaxy method. The crystal structure of the grown epilayer was confirmed to be a cubic structure by using Xray diffraction, and the optical properties of the layer were studied over a wide photon energy range from 1.0 to 8.5 eV at room temperature by using spectroscopic ellipsometry. The obtained data were analyzed for the critical points of the pseudodielectric function spectra, $<\varepsilon(E)>$ = $<\varepsilon_1(E)>$ + i $<\varepsilon_2(E)>$, such as the $E_0$, $E_1$, $E_2$, $E_0^{\prime}$, $E_1^{\prime}$ structures. Also, the pseudodielectric-function-related optical constants of CdS, such as the refractive index $n(E)$, the extinction coefficient $k(E)$, the reflectivity $R(E)$, and the absorption coefficient $\alpha(E)$, are presented and analyzed. Note that all the structures were observed, for the first time, at 300 K by using ellipsometric measurements.

Keywords: CdS, Spectroscopic ellipsometry, Hot-wall epitaxy, Dielectric functionCdS, Spectroscopic ellipsometry, Hot-wall epitaxy, Dielectric function