Characterization of Physical Properties of Thermally Evaporated Doped CdS Thin Films for Photovoltaics

Abstract:

Polycrystalline thin films of Cadmium Sulfide (CdS) have been extensively studied for application as a window layer in CdTe/CdS and CIGS/CdS thin film solar cells. Higher efficiency of solar cells is possible by a better conductivity of a window layer, which can be achieved by doping these films with suitable elements. CdS thin films were deposited on properly cleaned glass substrate by thermal evaporation technique under vacuum2×10-5mbar. Films were structurally characterized by using X-ray diffraction. The X-ray diffraction spectra showed that the thin films were polycrystalline in nature. Aluminum was doped chemically in as deposited and annealed thin films by immersing films in AlNO33.9H2O solutions respectively. Comparison between the effects of different doping ratios on the structural and optical properties of the films was investigated. Higher doping ratios have improved the electrical properties by decreasing the resistivity of the films and slightly changed the bandgap energy Eg. The grain size, strain, and dislocation density were calculated for as-deposited and annealed films.

• Periodical: Key Engineering Materials (Volumes 510-511)
• Pages: 156-162
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.510-511.156
• Online since: May 2012
• Authors: G.H. Tariq, Muhammad Anis-ur-Rehman
• Keywords: Aluminum (Al), CdS, Polycrystalline, Thermal Evaporation, Window Layer

References

[1] M.G. Faraj, K. Ibrahim and M.H. Eisa: Mat Sci Semicond Process (2011), doi: 10. 1016/j. mssp. (2010). 12. 016.

[2] M. Cao, Y. Sun, J. Wu, X. Chen, N. Dai: Journal of Alloys and Compounds 508 (2010), p.297.

[3] A.A. Yadav, E.U. Masumdar: J. Alloys Compd. (2011), doi: 10. 1016/j. jallcom. (2011). 02. 061.

[4] J. Han, C. Liao, T. Jiang, G. Fu, V. Krishnakumar, C. Spanheimer, G. Haindl, K. Zhao, A. Klein, W. Jaegermann: Materials Research Bulletin 46 (2011), p.194.

DOI: 10.1016/j.materresbull.2010.11.014

[5] K. Senthil, D. Mangalaraj, S.K. Narayandass: Applied Surface Science 169-170 (2001), p.476.

DOI: 10.1016/s0169-4332(00)00732-7

[6] K. El Assali, M. Boustani, A. Khiara, T. Bekkay, A. Outzourhit, E.L. Ameziane, J.C. Bernede, J. Pouzet: Physica Status Solidi A 178 (2000), p.701.

DOI: 10.1002/1521-396x(200004)178:2<701::aid-pssa701>3.0.co;2-3

[7] G. Sasikala, R. Dhnasekaran, C. Subramanian: Thin Solid Films 302 (1997), p.71.

[8] G. Brunthaler, M. Lang, A. Forstner, C. Giftge, D. Schikora, S. Fereira, H. Sitter, K. Lischka: Journal of Crystal Growth 138 (1994), p.559.

DOI: 10.1016/0022-0248(94)90868-0

[9] H. Moualkia, S. Hariech, M.S. Aida: Thin Solid Films 518 (2009), p.1259.

DOI: 10.1016/j.tsf.2009.04.067

[10] K. Ravichandran, P. Philominathan: Solar Energy 82 (2008), p.1062.

[11] X.L. Tong, D.S. Jiang, Y. Li, Z. M. Liu, M.Z. Luo: Physica Status Solidi A (2006); 203(8): 1992–8.

[12] H.C. Chou and A. Rohatgi: Journal of Electronic Materials 23 (1994), p.31.

[13] H. Chavez, M. Jordan, J.C. McClure, G. Lush, V.P. Singh: Journal of Mate- rials Science: Materials in Electronics 8 (1997), p.151.

[14] B. D. Cullity and S. R. Stock: Elements of X-Ray Diffraction 3rd Ed., Prentice Hall, NY (2001).

[15] P.K. Kalita, B.K. Sarma and H.L. Das: Bull. Mater. Sci., Vol. 23 (4) (2000), p.313.

[16] S. Lalitha, R. Sathyamoorthy, S. Senthilarasu, A. Subbarayan and K. Natarajan: Solar Energy Materials & Solar Cells Vol. 82 (2004), p.187.

DOI: 10.1016/j.solmat.2005.04.015

[17] M.A. Mahdi, S.J. Kasem, J.J. Hassen, A.A. Swadi, S.K.J. Al-Ani: Int. J. Nanoelectronics and Materials 2 (2009), p.163.

[18] S.D. Sartale, B.R. Sankapal, M.L. Steiner, A. Ennaui: Thin Solid Films 480 (2005), p.168.

[19] H. Khallaf, G. Chai, O. Lupan, L. Chowa, S. Park, A. Schulte: Applied Surface Science 255 (2009), p.4129.

[20] S.J. Ikhmayies, R.N. Ahmad-Bitar: Jordan Journal of Mechanical and Industrial Engineering, 4 (2010), p.111.

[21] A.A.J. Al-Douri, F.Y. Al-Shakily, M.F.A. Alias, and A.A. Alnajjar: Advances in Condensed Matter Physics Volume 2010, Article ID 947684, 5 pages doi: 10. 1155/2010/ 947684.

DOI: 10.1155/2010/947684

[22] J.C. Orlianges, C. Champeaux, P. Dutheil, A. Catherinot, T. Merle Mejean: Thin Solid Films (2011), doi: 10. 1016/j. tsf. 2010. 12. 139.

DOI: 10.1016/j.tsf.2010.12.139

[23] Z. He, G. Zhao, W. Weng, P. Du, G. Shen, G. Han: Vacuum 79 (2005) 14.

[24] F. Atay, V. Bilgin, I. Akyuz, S. Kose: Mater. Sci. Semicond. Process. 6 (2003) 197.