Quantum Wire-on-Well (WoW) Cell With Long Carrier Lifetime for Efficient Carrier Transport

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Title: Quantum Wire-on-Well (WoW) Cell With Long Carrier Lifetime for Efficient Carrier Transport
Authors: Sugiyama, M
Fujii, H
Katoh, K
Toprasertpong, K
Sodabanlu, H
Watanabe, K
Alonso Alvarez, D
Ekins-Daukes, NJ
Nakano, Y
Item Type: Conference Paper
Abstract: A quantum wire-on-well (WoW) structure, taking advantage of the layer undulation of an In- GaAs/GaAs/GaAsP superlattice grown on a vicinal substrate, was demonstrated to enhance the carrier collection from the confinement levels and extend the carrier lifetime (220 ns) by approximately 4 times as compared with a planar reference superlattice. Strained InGaAs/GaAs/GaAsP superlattices were grown on GaAs substrates under exactly the same condition except for the substrate misorientation (0o- and 6o- off). The growth on a 6o-off substrate induced significant layer undulation as a result of step bunching and non-uniform precursor incorporation between steps and terraces whereas the growth on a substrate without miscut resulted in planar layers. The undulation was the most significant for InGaAs layers, forming periodically aligned InGaAs nanowires on planar wells, a wire-on-well structure. As for the photocurrent corresponding to the sub-bandgap range of GaAs, the light absorption by the WoW was extended to longer wavelengths and weakened as compared with the planar superlattice, and almost the same photocurrent was obtained for both the WoW and the planar superlattice. Open-circuit voltage for the WoW was not affected by the longer-wavelength absorption edge and the same value was obtained for the two structures. Furthermore, the superior carrier collection in the WoW, especially under forward biases, improved fill factor compared with the planer superlattice.
Issue Date: 14-Sep-2015
Date of Acceptance: 14-Sep-2015
URI: http://hdl.handle.net/10044/1/34034
DOI: http://dx.doi.org/10.4229/EUPVSEC20152015-1AO.3.1
ISBN: 3936338396
Publisher: European Photovoltaic Solar Energy Conference and Exhibition
Start Page: 42
End Page: 47
Journal / Book Title: 31st European Photovoltaic Solar Energy Conference and Exhibition
Copyright Statement: © The Author(s) 2015.
Sponsor/Funder: Commission of the European Communities
Commission of the European Communities
Funder's Grant Number: 283798
Conference Name: 31st European Photovoltaic Solar Energy Conference and Exhibition
Publication Status: Published
Start Date: 2015-09-14
Finish Date: 2015-09-18
Appears in Collections:Physics
Experimental Solid State
Centre for Environmental Policy
Faculty of Natural Sciences

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