Behrooz Ghozati | University of Zimbabwe (original) (raw)
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Papers by Behrooz Ghozati
Radiation Physics and Chemistry, 2017
Despite extensive use of GaAs cells in space, silicon cells are still being used. The reason is t... more Despite extensive use of GaAs cells in space, silicon cells are still being used. The reason is that not only they provide a good compromise between efficiency and cost, but also some countries do not have the required technology for manufacturing GaAs. Behavior of a silicon cell under any levels of charged particle irradiation could be deducted from the results of a damage equivalent 1 MeV electron irradiation using the NASA EQflux open source software package. In this paper for the first time, we have studied the behavior of a silicon cell before and after 1 MeV electron irradiation with 10 14 , 10 15 and 10 16 electrons-cm −2 fluences, using SILVACO TCAD simulation software package. Simulation was carried out at room temperature under AM0 condition. Results reveal that open circuit voltage and efficiency decrease after irradiation while short circuit current shows a slight increase in the trend around 5 × 10 16 electrons-cm −2 , and short circuit current loss plays an important role on efficiency changes rather than open circuit voltage.
Solar Energy Materials and Solar Cells, 1998
Despite the commercial success of buried-contact solar cells, the performance of early generation... more Despite the commercial success of buried-contact solar cells, the performance of early generations of these devices has been limited by an effective high rear-surface recombination velocity. For a number of years, the double-sided buried-contact bifacial (DSBCB) solar cells have demonstrated improved rear-surface passivation with corresponding improvements in current and voltage. In the past, however, the fill factors of these devices have been significantly degraded due to shunting of the rear floating junction. These limitations have been overcome through the use of much higher sheet resistivities for the rear n-type layer. Experimental devices based on this new approach have achieved fill factors approaching 82% while simultaneously achieving open-circuit voltages in the vicinity of 670mV. Efficiencies in the range 17–18% without texturing, anti-reflection coatings, any form of light trapping, or even rear reflector have ben achieved on float-zone material.
DESCRIPTION Laboratory Instruments installation, commissioning, repair, upgrade and maintenance
Theoretical and experimental demonstrations have shown that excellent rear surface passivation ca... more Theoretical and experimental demonstrations have shown that excellent rear surface passivation can be attained by using a floating junction. The extent to which the rear is passivated, however, can be difficult to ascertain, particularly when there exist parasitic shunts across the floating junction. This paper presents a new experimental technique suitable for bifacial floating junction solar cells, that determines two
Radiation Physics and Chemistry, 2017
Despite extensive use of GaAs cells in space, silicon cells are still being used. The reason is t... more Despite extensive use of GaAs cells in space, silicon cells are still being used. The reason is that not only they provide a good compromise between efficiency and cost, but also some countries do not have the required technology for manufacturing GaAs. Behavior of a silicon cell under any levels of charged particle irradiation could be deducted from the results of a damage equivalent 1 MeV electron irradiation using the NASA EQflux open source software package. In this paper for the first time, we have studied the behavior of a silicon cell before and after 1 MeV electron irradiation with 10 14 , 10 15 and 10 16 electrons-cm −2 fluences, using SILVACO TCAD simulation software package. Simulation was carried out at room temperature under AM0 condition. Results reveal that open circuit voltage and efficiency decrease after irradiation while short circuit current shows a slight increase in the trend around 5 × 10 16 electrons-cm −2 , and short circuit current loss plays an important role on efficiency changes rather than open circuit voltage.
Solar Energy Materials and Solar Cells, 1998
Despite the commercial success of buried-contact solar cells, the performance of early generation... more Despite the commercial success of buried-contact solar cells, the performance of early generations of these devices has been limited by an effective high rear-surface recombination velocity. For a number of years, the double-sided buried-contact bifacial (DSBCB) solar cells have demonstrated improved rear-surface passivation with corresponding improvements in current and voltage. In the past, however, the fill factors of these devices have been significantly degraded due to shunting of the rear floating junction. These limitations have been overcome through the use of much higher sheet resistivities for the rear n-type layer. Experimental devices based on this new approach have achieved fill factors approaching 82% while simultaneously achieving open-circuit voltages in the vicinity of 670mV. Efficiencies in the range 17–18% without texturing, anti-reflection coatings, any form of light trapping, or even rear reflector have ben achieved on float-zone material.
DESCRIPTION Laboratory Instruments installation, commissioning, repair, upgrade and maintenance
Theoretical and experimental demonstrations have shown that excellent rear surface passivation ca... more Theoretical and experimental demonstrations have shown that excellent rear surface passivation can be attained by using a floating junction. The extent to which the rear is passivated, however, can be difficult to ascertain, particularly when there exist parasitic shunts across the floating junction. This paper presents a new experimental technique suitable for bifacial floating junction solar cells, that determines two