Lateral absorption measurements of InAs/GaAs quantum dots stacks: potential as intermediate band material for high efficiency solar cells

Cánovas, E., Martí, A., Luque, A., Farmer, C.D., Stanley, C.R., Sánchez, A.M., Ben, T. and Molina, S.I. (2010) Lateral absorption measurements of InAs/GaAs quantum dots stacks: potential as intermediate band material for high efficiency solar cells. Energy Procedia, 2(1), pp. 27-34. (doi: 10.1016/j.egypro.2010.07.006)

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Abstract

Prototypes based on InAs/GaAs QDs have been manufactured in order to realize the theoretically predicted high efficiency intermediate band solar cells (IBSCs). Unfortunately, until now, these prototypes have not yet demonstrated the expected increase in efficiency when compared with reference samples without IB material. One of the main arguments explaining this performance is the weak photon absorption in the QD-IB material, arising from a low density of QDs. In this work, we have analyzed the absorption coefficient of the IB material by developing a sample in an optical wave-guided configuration. This configuration allows us to illuminate the QDs laterally, increasing the path length for photon absorption. Using a multi-section metal contact device design, we were able to measure an absorption coefficient of ∼100 cm−1 around the band edge (∼1 eV ) defined by the VB◊IB transition in InAs/GaAs QD-IB materials. This figure, and its influence on the IBSC concept, is analyzed for this system.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Farmer, Dr Corrie and Stanley, Professor Colin
Authors: Cánovas, E., Martí, A., Luque, A., Farmer, C.D., Stanley, C.R., Sánchez, A.M., Ben, T., and Molina, S.I.
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
Journal Name:Energy Procedia
ISSN (Online):1876-6102
Published Online:04 August 2010

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