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International Journal of Photoenergy
Volume 2015 (2015), Article ID 483147, 8 pages
http://dx.doi.org/10.1155/2015/483147
Research Article

Improving Performance of CIGS Solar Cells by Annealing ITO Thin Films Electrodes

1Department of Photonics Engineering, Yuan Ze University, 135 Yuan-Tung Road, Chungli 320, Taiwan
2Department of Physics, Fu Jen Catholic University, 510 Zhongzheng Road, Xinzhuang District, New Taipei 242, Taiwan

Received 19 July 2015; Revised 11 October 2015; Accepted 22 October 2015

Academic Editor: Elias Stathatos

Copyright © 2015 Chuan Lung Chuang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Indium tin oxide (ITO) thin films were grown on glass substrates by direct current (DC) reactive magnetron sputtering at room temperature. Annealing at the optimal temperature can considerably improve the composition, structure, optical properties, and electrical properties of the ITO film. An ITO sample with a favorable crystalline structure was obtained by annealing in fixed oxygen/argon ratio of 0.03 at 400°C for 30 min. The carrier concentration, mobility, resistivity, band gap, transmission in the visible-light region, and transmission in the near-IR regions of the ITO sample were  cm−3,  cm2/Vs,  Ohm-cm, 3.2 eV, 89.1%, and 94.7%, respectively. Thus, annealing improved the average transmissions (400–1200 nm) of the ITO film by 16.36%. Moreover, annealing a copper-indium-gallium-diselenide (CIGS) solar cell at 400°C for 30 min in air improved its efficiency by 18.75%. The characteristics of annealing ITO films importantly affect the structural, morphological, electrical, and optical properties of ITO films that are used in solar cells.