Effect of Thickness and Temperature Variations on Some Structural, Optical and Electrical Properties of Electron Beam Deposited CdS Thin Films
Keywords:
II-VI thin films, CdS, electron beam deposition, activation energy, absorption coefficien, optical spectra, optical bandgap, electrical propertiesAbstract
Thin films of cadmium sulfide (CdS) by electron beam deposition on glass substrate. The structure of the films was investigated by X-ray diffraction (XRD). The CdS films were found to be crystalline and hexagonal with the c-axis perpendicular to the substrate. Annealing in air at 4000C greatly improved the crystallinity of the films as well as increasing their grain size. The optical properties of the films have been studied by transmission/reflection spectroscopy. The CdS films had optical bandgaps in the range 2.35-2.42 eV, which were dependent on the film thickness as well as on temperature. A reduction in the bandgap was also noticed for the annealed films. In addition, the single-effective oscillator parameters have been evaluated and their dependence upon film thickness discussed.
From d.c. electrical conductivity measurements it was found that the conductivity of the CdS films is a function of the thickness of the film, increasing with the thicker films. The electrical conductivity is greatly improved when the film is air-annealed. From values of the activation energy of conduction it was concluded that conduction is dominated by states close to the conduction band.
References
Brian Ray, II-VI Compounds, International Series of Monographs in the Science of the Solid State Vol.2 (1969)
A.S. Lahewil, Y. Al-Douri, U. Hashim, N.M. Ahmed, Structural and optical investigations of cadmium sulfide nanostructures for optoelectronic applications, Solar Energy, 86(11), 3234 (2012)
N. Amin, K. Sopian, M. Konagai, Sol. Energy Mater. Sol. Cells, 91(13), 1202(2007)
Kumar S, Sharma P, Sharma V. CdS nanofilms: Synthesis and the role of annealing on structural and optical properties. J Appl Phys. 2012;111(4)
Tsai K-A, Hsu Y-J. Graphene quantum dots mediated charge transfer of CdSe nanocrystals for enhancing photoelectrochemical hydrogen production. Appl Catal B Environ. 2015
Spirito D, Kudera S, Miseikis V, Giansante C, Coletti C, Krahne R. UV Light Detection from CdS Nanocrystal Sensitized Graphene Photodetectors at kHz Frequencies. J Phys Chem C. 2015;119(42):23859-23864.
Bao Z, Liu L, Yang X, et al. Synthesis and characterization of novel oxygenated CdSe window layer for CdTe thin film solar cells. Mater Sci Semicond Process. 2017;63:12-17
Shah NA, Mahmood W. Physical properties of sublimated zinc telluride thin films for solar cell applications. Thin Solid Films. 2013;544:307-312.
Hegde SS, Kunjomana AG, Prashantha M, Kumar C, Ramesh K. Photovoltaic structures using thermally evaporated SnS and CdS thin films. Thin Solid Films. 2013;545:543-547
Kumar P, Saxena N, Gupta V, Gao K, Singh F, Agarwal A. Effect of swift heavy ions on pulsed laser deposited Ag doped CdS nanocrystalline thin films. Adv Sci Lett. 2014;20(5- 6):977-983
Ferrá-González SR, Berman-Mendoza D, García-Gutiérrez R, et al. Optical and structural properties of CdS thin films grown by chemical bath deposition doped with Ag by ion exchange. Opt - Int J Light Electron Opt. 2014;125(4):1533-1536
K. Sheshan, Handbook of Thin Film Deposition Processes and Techniques, William Andrew Publishing/Noyes (2002)
Mahmood W, Shah NA. Study of cadmium sulfide thin films as a window layers. AIP Conf Proc. 2012;1476:178-182
Tariq GH, Anis-ur-Rehman M. Characterization of Physical Properties of Thermally Evaporated Doped CdS Thin Films for Photovoltaics. Key Eng Mater. 2012;510-511:156- 162
Moualkia H, Hariech S, Aida MS. Structural and optical properties of CdS thin films grown by chemical bath deposition. Thin Solid Films. 2009;518(4):1259-1262.
Aksay S, Polat M, Özer T, Köse S, Gürbüz G. Investigations on structural, vibrational, morphological and optical properties of CdS and CdS/Co films by ultrasonic spray pyrolysis. Appl Surf Sci. 2011;257(23):10072-10077
Cullity, B.D., Elements of X-ray Diffraction, Prentice Hall 2001 (3rd edition)
Max Fox , Optical Properties of Solids, Oxford Master Series in Condensed Matter Physics, OUP (2001)
S.H. Wemple, M. Di Domenico, Phys. Rev. B, 3 1338 (1971)
J. Tauc (ed) Amorphous and liquid semiconductors. (Springer, Berlin, 2012).
S. Mahanty, D. Basak, F. Rueda, M. Leon, Journal of Electronic Materials, 28 (5), 559-562 (1999)
K. El Assali, M. Boustani, A. Khiara, T. Bekkay, A. Outzourhit, E.L. Ameziane, J.C. Bernede, J. Pouzet, Physica Status Solidi, 178 (2) pp. 701-708 (2001)
Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2023 International Journal of Sciences: Basic and Applied Research (IJSBAR)
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
Authors who submit papers with this journal agree to the following terms.