AVS 56th International Symposium & Exhibition
    Electronic Materials and Processing Tuesday Sessions
       Session EM-TuP

Paper EM-TuP23
Investigation of Crystal Structure and New Ellipsometric Properties of Hexagonal CdS Epilayers

Tuesday, November 10, 2009, 6:00 pm, Room Hall 3

Session: Electronic Materials and Processing Poster Session
Presenter: D.J. Kim, Mokwon University, Korea
Authors: D.J. Kim, Mokwon University, Korea
Y.D. Choi, Mokwon University, Korea
J.W. Lee, Hanbat National University, Korea
J.C. Sur, Wonkwang University, Korea
Correspondent: Click to Email
High quality hexagonal CdS epilayer was grown on GaAs (111) substrates by the hot-wall epitaxy method. The crystal structure of the grown CdS epilayers was confirmed to be the hexagonal structure by X-ray diffraction pattern (XRD) and scanning electron microscopy (SEM) image. To explore binding states and their potential applications, the hexagonal structured CdS epilayers have been characterized using x-ray photoelectron spectroscopy (XPS). The optical properties of the hexagonal CdS epilayers were investigated in a wide photon energy range between 2.0-8.5 eV using spectroscopic ellipsometry (SE) at room temperature. The data obtained by SE were analyzed to find the critical points of the pseudodielectric function spectra, < ε ( E )>=< ε1( E )>+i< ε2( E )>, such as E0, E1A, E1B, E0', F1, and two E2 structures. In addition, the second derivative spectra, d2ε(E)/dE2, of the pseudodielectric function of hexagonal CdS epilayers were numerically calculated to determine the critical structures. Four structures, such as E0', F1, and two E2 structures, from 6.0 eV to 8.0 eV were observed, for the first time, at 300 K by ellipsometric measurements for the hexagonal CdS epilayers.