Impact of alloyed capping layers on the performance of In As quantum dot solar cells

Utrilla Lomas, Antonio David; Ulloa Herrero, José María; Gacevic, Zarko; Reyes, D.F.; Artacho Huertas, Irene; Ben, T.; González, D.; Hierro Cano, Adrián y Guzmán Fernández-González, Álvaro de (2016). Impact of alloyed capping layers on the performance of In As quantum dot solar cells. "Solar Energy Materials And Solar Cells", v. 144 ; pp. 128-135. ISSN 0927-0248. https://doi.org/10.1016/j.solmat.2015.08.009.

Descripción

Título: Impact of alloyed capping layers on the performance of In As quantum dot solar cells
Autor/es:
  • Utrilla Lomas, Antonio David
  • Ulloa Herrero, José María
  • Gacevic, Zarko
  • Reyes, D.F.
  • Artacho Huertas, Irene
  • Ben, T.
  • González, D.
  • Hierro Cano, Adrián
  • Guzmán Fernández-González, Álvaro de
Tipo de Documento: Artículo
Título de Revista/Publicación: Solar Energy Materials And Solar Cells
Fecha: Enero 2016
Volumen: 144
Materias:
Palabras Clave Informales: Solar cells, Quantum dots, Quantum Wells, Type-II, Carrier transport, Electron trapping
Escuela: E.T.S.I. Telecomunicación (UPM)
Departamento: Electrónica Física
Licencias Creative Commons: Reconocimiento - Sin obra derivada - No comercial

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Resumen

The impact of using thin GaAs(Sb)(N) capping layers (CLs) on InAs/GaAs quantum dots (QDs) is investigated for their application in solar cell devices. We demonstrate the ability to combine strain-balancing techniques with band engineering approaches through the application of such CLs. Extended photo-response is attainable by means of an independent tunability of the electron and hole confinements in the QD. Moreover, the CL acts itself as a quantum well (QW), providing an additional photoresponse, so that the devices work as hybrid QD-QW solar cells. The use of a GaAsSb CL is particularly beneficial, providing devices with efficiencies under AM1.5 conditions 20% higher than standard GaAs-capped QDs. This is mainly due to a significant increase in photocurrent beyond the GaAs bandgap, leading to an enhanced short-circuit current density (J(sc)). The addition of N to the CLs, however, produces a strong reduction in J(sc). This is found to be related to carrier collection problems, namely, hindered electron extraction and retrapping in the CLs. Nevertheless, the application of reverse biases induces a release of the trapped carriers assisted by a sequential tunneling mechanism. In the case of GaAsN CLs, this leads to a complete carrier collection and reveals an even higher QD-QW-related photocurrent than when using a GaAsSb CL. The hindered carrier collection is stronger in the case of the quaternary CLs, likely due to the faster recombination rates in the type-I GaAsSbN/GaAs QW structure as compared to the type-II ternary counterparts. Nevertheless, alternative approaches, such as the use of a thinner CL or a short-period superlattice CL, lead to significant improvements, demonstrating a great potential for the quaternary CLs under a proper device design.

Proyectos asociados

TipoCódigoAcrónimoResponsableTítulo
Gobierno de EspañaMAT2013-47102-C2-2-RSin especificarSin especificarSin especificar
Gobierno de EspañaMAT2010-15206Sin especificarSin especificarSin especificar

Más información

ID de Registro: 45993
Identificador DC: http://oa.upm.es/45993/
Identificador OAI: oai:oa.upm.es:45993
Identificador DOI: 10.1016/j.solmat.2015.08.009
URL Oficial: http://www.sciencedirect.com/science/article/pii/S0927024815003967
Depositado por: Memoria Investigacion
Depositado el: 23 May 2017 16:56
Ultima Modificación: 23 May 2017 16:56
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