First Demonstration of AlxGa1-xAs/Si Monolithic Tandem Solar Cells Grown by Metalorganic Chemical Vapor Deposition

Abstract
Al0.1Ga0.9As/Si and thin GaAs/Si monolithic two-terminal tandem cells, which are fabricated by thermal diffusion and metalorganic chemical vapor deposition (MOCVD), have exhibited the active area efficiencies of 16.3% and 15.6%, and the total area efficiencies of 13.8% and 13.1%, respectively. The key technologies required to fabricate the successful tandem cell are the formation of the p+-n junction in the Si substrate and the matching of the photocurrents between the top and the bottom cells.