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

Utrilla Lomas, Antonio David and Reyes, D.F. and Llorens Molina, Juan Antonio and Artacho Huertas, Irene and Ben, T. and González Lamuño, D. and Gacevic, Zarko and Kurtz de Griñó, Alejandro and Guzmán, Luis Alberto and Hierro Cano, Adrián and Ulloa Herrero, José María (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:
  • Utrilla Lomas, Antonio David
  • Reyes, D.F.
  • Llorens Molina, Juan Antonio
  • Artacho Huertas, Irene
  • Ben, T.
  • González Lamuño, D.
  • Gacevic, Zarko
  • Kurtz de Griñó, Alejandro
  • Guzmán, Luis Alberto
  • Hierro Cano, Adrián
  • Ulloa Herrero, José María
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

TypeCodeAcronymLeaderTitle
Madrid Regional GovernmentS2013/MAE-2780MADRID-PVAntonio Martí VegaMateriales, dispositivos y tecnología para el desarrollo de la industria fotovoltaica
Government of SpainTEC2015-64189-C3-2-RUnspecifiedUnspecifiedUnspecified
Government of SpainMAT2013-47102-C2-2-RUnspecifiedUnspecifiedUnspecified
Government of SpainAIC-B_2011-0806UnspecifiedUnspecifiedUnspecified

More information

Item ID: 46040
DC Identifier: http://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/S0927024816303427
Deposited by: Memoria Investigacion
Deposited on: 24 May 2017 15:38
Last Modified: 20 Mar 2019 18:18
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