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Proceedings Paper

Characteristic improvements of vertically aligned columnar quantum dot solar cell with a GaAsSb capping layer
Author(s): Wei-Sheng Liu; Hsin-Lun Tseng; Tien-Hao Huang; Ting-Fu Chu; Po-Chen Kuo; Fu-Hsiang Tsao; Jen-Inn Chyi
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Paper Abstract

This study demonstrates the feasibility of improving the optical properties of a vertically aligned quantum dot (QD) structure and the performance of a quantum dot intermediate band solar cell (QD-IBSC) by capping a GaAsSb layer on the InAs QD. Experimental results indicate that this capping process significantly improves dot-size uniformity because of the strain modification in vertically aligned dot layer growth. A solar cell device with an InAs/GaAsSb columnar dot structure increases the short-circuit current density (Jsc) by 8.8%, compared to a GaAs reference cell. This dot structure also increases quantum efficiency by up to 1200 nm through the absorption of lower-energy photons. The InAs/GaAsSb QD-IBSC also improves the open-circuit voltage (Voc), indicating a reduction in misfit defect density and recombination current density. Power dependent photoluminescence (PL) and time resolved photoluminescence (TRPL) measurement are employed to characterize the optical properties of typical InAs/GaAs type-I and InAs/GaAsSb type-II vertically aligned quantum dot structure. Extended carrier lifetime is demonstrated in the columnar InAs/GaAsSb type-II band structure. The results of this study confirm the ability and thermal stability of a columnar InAs/GaAsSb QD structure to enhance device performance.

Paper Details

Date Published: 31 October 2012
PDF: 10 pages
Proc. SPIE 8471, Next Generation (Nano) Photonic and Cell Technologies for Solar Energy Conversion III, 84710K (31 October 2012); doi: 10.1117/12.929412
Show Author Affiliations
Wei-Sheng Liu, Yuan Ze Univ. (Taiwan)
Hsin-Lun Tseng, Yuan Ze Univ. (Taiwan)
Tien-Hao Huang, Yuan Ze Univ. (Taiwan)
Ting-Fu Chu, Yuan Ze Univ. (Taiwan)
Po-Chen Kuo, Yuan Ze Univ. (Taiwan)
Fu-Hsiang Tsao, Yuan Ze Univ. (Taiwan)
Jen-Inn Chyi, National Central Univ. (Taiwan)

Published in SPIE Proceedings Vol. 8471:
Next Generation (Nano) Photonic and Cell Technologies for Solar Energy Conversion III
Loucas Tsakalakos, Editor(s)

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