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International Journal of Photoenergy
Volume 2013 (2013), Article ID 539765, 5 pages
http://dx.doi.org/10.1155/2013/539765
Research Article

Enhanced Efficiency of GaAs Single-Junction Solar Cells with Inverted-Cone-Shaped Nanoholes Fabricated Using Anodic Aluminum Oxide Masks

1Department of Electrical and Computer Engineering, Ajou University, Suwon 443-749, Republic of Korea
2Institute of Applied Materials Science, Vietnam Academy of Science and Technology, Ho Chi Minh 70999, Vietnam
3Department of Energy Systems Research, Ajou University, Suwon 443-749, Republic of Korea

Received 15 June 2013; Accepted 10 July 2013

Academic Editor: Leonardo Palmisano

Copyright © 2013 Kangho Kim 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

The GaAs solar cells are grown by low-pressure metalorganic chemical vapor deposition (LP-MOCVD) and fabricated by photolithography, metal evaporation, annealing, and wet chemical etch processes. Anodized aluminum oxide (AAO) masks are prepared from an aluminum foil by a two-step anodization method. Inductively coupled plasma dry etching is used to etch and define the nanoarray structures on top of an InGaP window layer of the GaAs solar cells. The inverted-cone-shaped nanoholes with a surface diameter of about 50 nm are formed on the top surface of the solar cells after the AAO mask removal. Photovoltaic and optical characteristics of the GaAs solar cells with and without the nanohole arrays are investigated. The reflectance of the AAO nanopatterned samples is lower than that of the planar GaAs solar cell in the measured range. The short-circuit current density increased up to 11.63% and the conversion efficiency improved from 10.53 to 11.57% under 1-sun AM 1.5 G conditions by using the nanohole arrays. Dependence of the efficiency enhancement on the etching depth of the nanohole arrays is also investigated. These results show that the nanohole arrays fabricated with an AAO technique may be employed to improve the light absorption and, in turn, the conversion efficiency of the GaAs solar cell.