CdS Thin Films Deposited by a Modified Chemical Bath Deposition Method
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Abstract
Cds thin films were deposited on glass slide substrates by a modified chemical bath deposition technique using CdSO4 as the cadmium source. SC (NH2)2 as the sulfur source and NH3 as the complexing agent in deionized water bath. The modification to the traditional technique consists in applying the rotated substrate holder with controlled speed instead of using magnetic stirrer or a bath stirred by an impeller. As-deposited films were thermally annealed in a controlled N2 atmosphere. The annealing temperature was varied from 100-500 °C. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) techniques were used to determine the morphology, compositions and crystalline structure of the films. The gradual structural transition from zincblende for the as-deposited CdS to wurtzite structure for the film annealed at 400 °C, the critical point of the phase transformation, was observed by XRD and optical transmission studies. Electrical sheet resistance of CdS thin films as a function of annealing temperature were also investigated. The appearance of the minimum sheet resistance of samples annealed at 200 – 300 °C, being around 4.6 x 104 Ω/square, was obtained in the darkness and under illumination conditions by using an ELH halogen lamp.
Keywords: Cds thin films, chemical bath deposition, optical transmission
Corresponding author: E-mail: kwngamni@kmitl.ac.th
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References
[2] J. Vidal, O. Vigil, O. Melo, N. Lopez, and O. Zelaya – Angel, Accurate Control of Thin Film CdS Growth Process by Adjusting the Chemical Bath Deposition Parameter, Mat. Chem. Phys., 6(3), 1999, 1139-1142.
[3] G. Sasikala, P. Thilakan, and C. Subramanian, Modification in the Chemical Bath Deposition Apparatus, Growth and Characterization of CdS Semiconducting Thin Films for Photovoltaic Applications, Sol. Energy Sol. Cells, 62(1), 2000, 275-293.
[4] M.E. Calixto, and P.J. Sebastian, A Comparison of the Properties of Chemical Vapor Transport Deposited CdS Thin Films Using Different Precursors, Sol. Energy Sol. Cells, 59(2), 1999, 65-74.
[5] T. Yodo, and S. Tanaka, Investigation of CdS Thin Films: Structural, Optical and Electrical Properties, J. Appl. Phys., 72(11), 1992, 2781-2890.
[6] X. Mathew and P.J. Sebastian, Optical Properties of Electrodeposited CdTe Thin Films., Sol. Energy Sol. Cells, 59(10), 1999, 85-98.
[7] U. Rau, and H.W. Schock, Electronic Properties of Cu(In,Ga)Se2 Heterojunction Solar Cells Recent Achievements, Current Understanding, and Future Challenges, Appl. Phys. A, 69(2), 1999, 131-147.
[8] E.P. Warekois, M.C. Lavine, A.N. Mariano, and H.C. Gatos, Structural Investigations of CdS Single Crystal, J. Appl. Phys., 33(2), 1962, 690-696.
[9] J.M. Don, and J. Herrero, Chemical Bath Deposition of CdS Thin Films: An Approach to the Chemical Mechanism Through Study of the Film Microstructure, J. Electrochem. Soc., 144(11), 1997, 4081-4091.
[10] R. Ortega- Borges, and D. Lincot, Mechanism of Chemical Bath Deposition of Cadmium Sulfide Thin Films in the Ammonia Thiourea System, J. Electrochem. Soc., 140(5), 1993, 3464 – 3470.
[11] T. Yamaguchi, Y. Yamamoto, T. Tanaka, and A. Yoshida, Preparation and Characterization of (Cd,Zn)S Thin Films by Chemical Bath Deposition for Photovoltaic Devices, Thin Solid Films, 343 – 344(10), 1999, 516-519.
[12] T. Gaewdang, and Ng. Gaewdang, Properties of Cadmium Sulfide Thin Films Prepared by Chemical Bath Deposition Method, The Journal of Science Khonkaen University, 28(4), 2000, 44-52.
[13] Ng. Gaewdang, T. Wongcharoen and T. Gaewdang, Ibfluence of Nitrogen Annealing on Properties of Cadmium Sulfide Thin Films Prepared by Chemical Bath Deposition Method, 26th Congress on Science and Technology of Thailand, 2000, 246.
[14] O. Zelaya- Angel, J.J. Alvarado- Gil, R. Lozada- Morales, H. Vargas, and A.F. da Silva, Investigations of band Gap Shift on CdS – Annealed Films, Appl. Phys. Lett., 64(2), 1994. 291-293.
[15] L. Hernandez, O. de Melo, O. Zelaya – Angel, R. Lozada – Morales, and E. Puron, Electro-Optical Characterization of Sulfur Annealed Chemical Bath Deposited CdS Films, J. Electrochem. Soc., 141(1), 1994, 3238 – 3242.
[16] M. Ichimura, F. Goto, and E. Arai, Structural and Optical Characterization of CdS Films Grown by Photochemical Deposition, J. Appl. Phys. 85(10), 1999, 7411 – 7417.
[17] S.A. Tomas, O. Vigil, J.J. Alvarado – Gil, R. Lozada- Morales, O. Zelaya – Angel, H. Vargas, and A.F. da Silva, Influence of Thermal Annealings in Different Atmospheres on the Band Gap Shift and Resisticity of CdS Thin Films, J. Appl. Phys., 78(3), 1995, 2204-2206.
[18] T.L. Chu. S. Shirley, S. Chu N. Schultz, C. Wang and C.Q. Wu, Solution Grown Cadmium Sulfide Films for Photovoltaic Devices, J. Electrochem, Soc., 139(9), 1992, 2232-2244.
[19] Ng. Gaewdang and T. Graewdang, Preparation and Some Prperties of Cadmium Sulfide Semiconductor, Journal of Science Ladkrabang, 9(1), 1999, 25-29.