Resistance considerations for stacked small multi-junction photovoltaic cells

摘要

In this paper we propose a stacked multi-junction solar cell design that allows the intimate contact of the individual cells while maintaining low resistive losses. The cell design is presented using an InGaP and GaAs multi-junction cell as an illustrative example. However, the methodologies presented in this paper can be applied to other III-V cell types including InGaAs and InGaAsP cells. The main benefits of the design come from making small cells, on the order of 2×10⁻³ cm². Simulations showed that series resistances should be kept to less than 5 Ω for devices up to 400 μm in diameter to keep resistance power losses to less than 1%. Low resistance AuBe/Ni/Au ohmic contacts to n-type InGaP are also demonstrated with contact resistivity of 5×10−6 Ωcm⁻² when annealed at 420°C.