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International Journal of Photoenergy
Volume 2012 (2012), Article ID 206174, 5 pages
http://dx.doi.org/10.1155/2012/206174
Research Article

Characteristics of GaN/InGaN Double-Heterostructure Photovoltaic Cells

1Institute of Microelectronics and Department of Electrical Engineering, Advanced Optoelectronic Technology Center, Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 70101, Taiwan
2Graduate Institute of Precision Engineering, National Chung Hsing University, Taichung 402, Taiwan
3Electronics and Optoelectronics Research Laboratories, Industrial Technology Research Institute, Chutung, Hsinchu 310, Taiwan
4Department of Electronic Engineering, Chang-Gung University, Taoyuan 333, Taiwan

Received 29 March 2012; Revised 18 June 2012; Accepted 26 June 2012

Academic Editor: Wayne A. Anderson

Copyright © 2012 Ming-Hsien Wu 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 p-GaN/i-InxGa1xN/n-GaN double-heterostructure photovoltaic (PV) cells have been fabricated and the theoretical photovoltaic properties were also calculated in this work. From theoretical simulation, higher efficiency can be obtained in GaN/InGaN double-heterostructure photovoltaic cells with higher In composition in i-InGaN intrinsic layer. GaN/InGaN double-heterostructure photovoltaic cells with In compositions of 10%, 12%, and 14% were fabricated and characterized for demonstrating with the simulated results. The corresponding photoelectrical conversion efficiency of fabricated GaN/InGaN photovoltaic cells with In compositions of 10%, 12%, and 14% is 0.51%, 0.53%, and 0.32% under standard AM 1.5G measurement condition, respectively. GaN/InGaN photovoltaic cells with In composition of 10% showed high open-circuit voltage (Voc) of 2.07 V and fill factor (F.F.) of 80.67%. The decrease of Voc and FF was observed as In composition increasing from 10% to 14%. For comparing with the fabricated GaN/InGaN photovoltaic cells, theoretical conversion efficiency of GaN/InGaN photovoltaic cells with In compositions of 10%, 12%, and 14%, is 1.80%, 2.04%, and 2.27%, respectively. The difference of GaN/InGaN photovoltaic properties between theoretical simulation and experimental measurement could be attributed to the inferior quality of InGaN epilayer and GaN/InGaN interface generated as the increase of In composition.