Thin GaAsSb capping layers for improved performance of InAs/GaAs quantum dot solar cells

Utrilla Lomas, Antonio David, Reyes, D.F., Llorens Molina, Juan Antonio, Artacho Huertas, Irene ORCID: https://orcid.org/0000-0003-0213-2966, Ben, T., González Lamuño, D., Gacevic, Zarko ORCID: https://orcid.org/0000-0003-0552-2169, Kurtz de Griñó, Alejandro, Guzmán, Luis Alberto, Hierro Cano, Adrián ORCID: https://orcid.org/0000-0002-0414-4920 and Ulloa Herrero, José María ORCID: https://orcid.org/0000-0002-5679-372X (2016). Thin GaAsSb capping layers for improved performance of InAs/GaAs quantum dot solar cells. "Solar Energy Materials and Solar Cells", v. 159 ; pp. 282-289. ISSN 0927-0248. https://doi.org/10.1016/j.solmat.2016.09.006.

Description

Title: Thin GaAsSb capping layers for improved performance of InAs/GaAs quantum dot solar cells
Author/s:
Item Type: Article
Título de Revista/Publicación: Solar Energy Materials and Solar Cells
Date: January 2016
ISSN: 0927-0248
Volume: 159
Subjects:
Freetext Keywords: Solar cells; Quantum dots; GaAsSb; Capping layers; Type-II; Carrier collection efficiency
Faculty: E.T.S.I. Telecomunicación (UPM)
Department: Ingeniería Electrónica
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

This work reports on the benefits from using thin GaAsSb capping layers (CLs) on InAs/GaAs quantum dot (QD) solar cells. The application of such CLs allows the tunability of the QD ground state, switching the QD-CL band alignment from type I to type II for high Sb contents and extending the photoresponse beyond 1.5 µm. Two different structures with ~10% and ~20% Sb contents in the CL (type-I and type-II band alignments, respectively) are explored, leading to efficiency improvements over a reference InAs/GaAs QD solar cell of 20% and 10%, respectively. In general, a significant increase in short-circuit current density (Jsc) is observed, partially due to the extended photocurrent spectrum and the additional contribution of the CL itself. Particularly, for a moderate Sb content, an improved carrier collection efficiency is also found to be a main reason for the Jsc increase. Calculations from an 8×8 k·p method suggest the attribution of such an improvement to longer carrier lifetimes in the wetting layer-CL structure due to the transition to a type-II band alignment. Open-circuit voltages (Voc) exceeding that of a reference QD solar cell are demonstrated under light concentration using GaAsSb CLs, which proves that the Voc is not limited by the low bandgap CLs. Moreover, the highest value is obtained for the high Sb content type-II structure, despite the higher accumulation of strain and the lower effective bandgap. Indeed, the faster Voc increase with light power found in the latter case leads to an Voc even larger than the effective bandgap.

Funding Projects

Type
Code
Acronym
Leader
Title
Madrid Regional Government
S2013/MAE-2780
MADRID-PV
Antonio Martí Vega
Materiales, dispositivos y tecnología para el desarrollo de la industria fotovoltaica
Government of Spain
TEC2015-64189-C3-2-R
Unspecified
Unspecified
Unspecified
Government of Spain
MAT2013-47102-C2-2-R
Unspecified
Unspecified
Unspecified
Government of Spain
AIC-B_2011-0806
Unspecified
Unspecified
Unspecified

More information

Item ID: 46040
DC Identifier: https://oa.upm.es/46040/
OAI Identifier: oai:oa.upm.es:46040
DOI: 10.1016/j.solmat.2016.09.006
Official URL: http://www.sciencedirect.com/science/article/pii/S...
Deposited by: Memoria Investigacion
Deposited on: 24 May 2017 15:38
Last Modified: 30 Nov 2022 09:00
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