Reducing carrier escape in the InAs/GaAs quantum dot intermediate band solar cell

Antolín, E., Martí, A., Farmer, C., Linares, P. G., Hernández, E., Sánchez, A. M., Ben, T., Molina, S. I., Stanley, C. and Luque, A. (2010) Reducing carrier escape in the InAs/GaAs quantum dot intermediate band solar cell. Journal of Applied Physics, 108(6), 064513. (doi: 10.1063/1.3468520)

Abstract

Intermediate band solar cells (IBSCs) fabricated to date from In(Ga)As/GaAs quantum dot arrays (QD-IBSC) exhibit a quantum efficiency (QE) that extends to below bandgap energies. However, the production of sub-bandgap photocurrent relies often on the thermal and/or tunneling escape of carriers from the QDs, which is incompatible with preservation of the output voltage. In this work, we test the effectiveness of introducing a thick GaAs spacer in addition to an InAlGaAs strain relief layer (SRL) over the QDs to reduce carrier escape. From an analysis of the QE at different temperatures, it is concluded that escape via tunneling can be completely blocked under short-circuit conditions, and that carriers confined in QDs with an InAlGaAs SRL exhibit a thermal escape activation energy over 100 meV larger than in the case of InAs QDs capped only with GaAs.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Farmer, Dr Corrie and Stanley, Professor Colin
• Authors: Antolín, E., Martí, A., Farmer, C., Linares, P. G., Hernández, E., Sánchez, A. M., Ben, T., Molina, S. I., Stanley, C., and Luque, A.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Journal Name: Journal of Applied Physics
• Journal Abbr.: J. Appl. Phys.
• ISSN: 0021-8979
• ISSN (Online): 1089-7550
• Published Online: 23 September 2010