Monolithic, two-terminal InP/Ga0.47In0.53As tandem solar cells

Recent research has been directed towards the development of two-terminal, i.e., series-connected, monolithic InP/Ga_0.47In _0. tandem cells. Two fundamental problems must be addressed to realize high-performance, two-terminal cells. First, an ohmic electrical interconnect between the top and bottom subcells must be integrated into the monolithic structure to connect the subcells in series. The optical and joule losses in the interconnect should be negligible compared to the tandem cell output. Second, because the subcells are connected in series, techniques for matching the subcell photocurrents, and maximizing the tandem cell photocurrent, under relevant solar spectra, are necessary to achieve the highest tandem cell efficiency. The authors describe preliminary progress towards solving these problems, and outline directions for future work