Title

Characterization of gallium-doped CdS thin films grown by chemical bath deposition

Authors

Authors

H. Khallaf; G. Chai; O. Lupan; L. Chow; S. Park;A. Schulte

Abstract

Ga-doped CdS thin films, with different [Ga]/[Cd] ratios, were grown using chemical bath deposition. The effect of Ga-doping on optical properties and bandgap of CdS films is investigated. Resistivity, carrier density, and mobility of doped films were acquired using Hall effect measurements. Crystal structure as well as crystal quality and phase transition were determined using X-ray diffraction (XRD) and Micro-Raman spectroscopy. Film morphology was studied using scanning electron microscopy, while film chemistry and binding states were studied using X-ray photoelectron spectroscopy (XPS). A minimum bandgap of 2.26 eV was obtained at [Ga]/[Cd] ratio of 1.7 x 10(2). XRD studies showed Ga3+ ions entering the lattice substitutionally at low concentration, and interstitially at high concentration. Phase transition, due to annealing, as well as induced lattice defects, due to doping, were detected by Micro-Raman spectroscopy. The highest carrier density and lowest resistivity were obtained at [Ga]/[Cd] ratio of 3.4 x 10(2). XPS measurements detect an increase in sulfur deficiency in doped films. (C) 2008 Elsevier B. V. All rights reserved.

Journal Title

Applied Surface Science

Volume

255

Issue/Number

7

Publication Date

1-1-2009

Document Type

Article

First Page

4129

Last Page

4134

WOS Identifier

WOS:000262245500039

ISSN

0169-4332

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