title: The realistic energy yield potential of GaAs-on-Si tandem solar cells: a theoretical case study.
abstract: Si based tandem solar cells represent an alternative to traditional compound III-V multijunction cells as a promising way to achieve high efficiencies. A theoretical study on the energy yield of GaAs on Si (GaAs/Si) tandem solar cells is performed to assess their energy yield potential under realistic illumination conditions with varying spectrum. We find that the yield of a 4-terminal contact scheme with thick top cell is more than 15% higher than for a 2-terminal scheme. Furthermore, we quantify the main losses that occur for this type of solar cell under varying spectra. Apart from current mismatch, we find that a significant power loss can be attributed to low irradiance seen by the sub-cells. The study shows that despite non-optimal bandgap combination, GaAs/Si tandem solar cells have the potential to surpass 30% energy conversion efficiency.
authors.forename: Haohui
authors.initials: H
authors.lastname: Liu
authors.forename: Zekun
authors.initials: Z
authors.lastname: Ren
authors.forename: Zhe
authors.initials: Z
authors.lastname: Liu
authors.forename: Armin G
authors.initials: AG
authors.lastname: Aberle
authors.forename: Tonio
authors.initials: T
authors.lastname: Buonassisi
authors.forename: Ian Marius
authors.initials: IM
authors.lastname: Peters