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Showing papers by "Keisuke Ohdaira published in 2006"

Journal Article•DOI•
Influence of stacked Ge islands on the dark current–voltage characteristics and the conversion efficiency of the solar cells

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Arnold C. Alguno1, Noritaka Usami1, Keisuke Ohdaira1, Wugen Pan1, Misumi Tayanagi1, Kazuo Nakajima1 •
Tohoku University1
05 Jun 2006-Thin Solid Films
TL;DR: In this article, the authors used a two-diode model to analyze the dark J-V characteristics of Ge island solar cells and found that the minority carrier diffusion and the recombination current components increase as a function of the stacked Ge island layers.

3 citations

Journal Article•DOI•
High-Efficiency Concave and Conventional Solar Cell Integration System Using Focused Reflected Light

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Keisuke Ohdaira1, Kozo Fujiwara, Wugen Pan, Noritaka Usami, Kazuo Nakajima •
Japan Advanced Institute of Science and Technology1
08 Mar 2006-Japanese Journal of Applied Physics
TL;DR: In this paper, a concave Si single crystal prepared by mechanical polishing was successfully processed to a solar cell with a conversion efficiency of 14.7% and the total efficiency of this system became as high as 16.3%.
Abstract: A concave Si single crystal prepared by mechanical polishing was successfully processed to a solar cell with a conversion efficiency of 14.7%. The concave cell could focus its reflection to a small spot, which generated further output in a conventional Si solar cell placed at the focal point. The total efficiency of this system became as high as 16.3%. The calculation results clearly show that there is room for further improvement of the total conversion efficiency by the correspondence between the small cell area and the focused spot size as well as the increase in concentration ratio.

3 citations