Type II GaSb/GaAs quantum rings with extended photoresponse for efficient solar cells

Carrington, Peter James and Montesdeoca Cardenes, Denise and Fujita, Hiromi and James Asirvatham, Juanita Saroj and Wagener, Magnus and Botha, Johannes Reinhardt and Marshall, Andrew Robert Julian and Krier, Anthony (2016) Type II GaSb/GaAs quantum rings with extended photoresponse for efficient solar cells. Proceedings of SPIE, 9937: 993708. ISSN 0277-786X

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The introduction of GaSb quantum dots (QDs) within a GaAs single junction solar cell is attracting increasing interest as a means of absorbing long wavelength photons to extend the photoresponse and increase the short-circuit current. The band alignment in this system is type-II, such that holes are localized within the GaSb QDs but there is no electron confinement. Compared to InAs QDs this produces a red-shift of the photoresponse which could increase the short-circuit current and improve carrier extraction. GaSb nanostructures grown by molecular beam epitaxy (MBE) tend to preferentially form quantum rings (QRs) which are less strained and contain fewer defects than the GaSb QDs, which means that they are more suitable for dense stacking in the active region of a solar cell to reduce the accumulation of internal strain and enhance light absorption. Here, we report the growth and fabrication of GaAs based p-i-n solar cells containing ten layers of GaSb QRs. They show extended long wavelength photoresponse into the near-IR up to 1400 nm and enhanced short-circuit current compared to the GaAs control cell due to absorption of low energy photons. Although enhancement of the short-circuit current was observed, the thermionic emission of holes was found to be insufficient for ideal operation at room temperature.

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Proceedings of SPIE
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P. J. Carrington; D. Montesdeoca; H. Fujita; J. James; M. C. Wagener; J. R. Botha; A. R. J. Marshall; A. Krier Type II GaSb/GaAs quantum rings with extended photoresponse for efficient solar cells Proc. SPIE 9937, Next Generation Technologies for Solar Energy Conversion VII, 993708 (23 September 2016); doi: 10.1117/12.2236957 Copyright 2016 Society of Photo Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.
?? solar cellsgasbmolecular beam epitaxyphotoluminescence ??
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18 Oct 2016 10:56
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03 Feb 2024 00:37