Experimental evidence for impurity photovoltaic effect in GaAs/AlGaAs based graded bandgap multi-layer solar cells

DHARMADASA, I, ELSHERIF, O. and TOLAN, G.J. (2010). Experimental evidence for impurity photovoltaic effect in GaAs/AlGaAs based graded bandgap multi-layer solar cells. In: Proceedings of the 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion. EU PVSEC, 583-586.

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Link to published version:: 10.4229/25thEUPVSEC2010-1DV.3.11


A graded bandgap multi-layer solar cell device structure was designed to absorb UV, visible and IR radiation, and to incorporate impact ionisation and impurity photovoltaic effects within one device. The design was experimentally tested with a well researched material system, MOVPE grown GaAs/AlGaAs. Open circuit voltages of ~1175 mV with highest possible FF values (0.83-0.87) have been observed [1,3]. These parameters were independently verified by measuring in five different laboratories in Europe and United States including NREL. While the work is continuing to increase short circuit current density values, these devices were tested to explore the experimental evidence of impurity PV effect, as expected from this design. Responsivity measurements and PV activity in dark conditions have been carried out to investigate impurity PV effect in these devices. Responsivity measurements indicate current collection in the infra-red region confirming the contribution from IR photons. The IV measurements in dark conditions produce open circuit voltages exceeding 750 mV confirming the contribution from surrounding heat radiation. The new features of graded bandgap devices enable impurity PV effect to dominate and create useful charge carriers, suppressing detrimental recombination process. These experimental results will be presented in this paper.

Item Type: Book Section
Research Institute, Centre or Group: Materials and Engineering Research Institute > Thin Films Research Centre > Electronic Materials and Sensors Research Group
Identification Number: 10.4229/25thEUPVSEC2010-1DV.3.11
Depositing User: Hilary Ridgway
Date Deposited: 19 Feb 2015 10:36
Last Modified: 19 Feb 2015 10:36
URI: http://shura.shu.ac.uk/id/eprint/9458

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