Memorias de investigación
Research Publications in journals:
Thin GaAsSb capping layers for improved performance of InAs/GaAs quantum dot solar cells
Year:2016
Research Areas
  • Solar cells
Information
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.
International
Si
JCR
Si
Title
Solar Energy Materials And Solar Cells
ISBN
0927-0248
Impact factor JCR
5,03
Impact info
Volume
159
10.1016/j.solmat.2016.09.006
Journal number
From page
282
To page
289
Month
SIN MES
Ranking
Participants
Research Group, Departaments and Institutes related
  • Creador: Grupo de Investigación: Grupo de Dispositivos Semiconductores del ISOM
  • Centro o Instituto I+D+i: Instituto Universitario de Sistemas Optoelectrónicos y Microtecnología
  • Grupo de Investigación: Silicio y Nuevos Conceptos para Células Solares
  • Departamento: Ingeniería Electrónica