Seidel, U. ; Schimper, H.-J. ; Sagol, E. ; Bloeck, U. ; Schwarzburg, K. ; Hannappel, T.: InGaAs/GaAsSb tunnel junction employed in a low band gap tandem solar cell. In: Poortman, J. [u.a.] [Eds.] : Twentyfirst European Photovoltaic Solar Energy Conference : proceedings of the international conference held in Dresden, Germany, 4 - 8 September 2006. München: WIP Renewable Energies, 2006. - ISBN 3-936338-20-5, p. 426-429
Abstract:
Monolithically, MOCVD-grown low band gap tandem solar cells composed of InGaAs (Eg=0.75 eV) and InGaAsP (Eg=1.05 eV), lattice-matched to InP were investigated. The subcells in the tandem structure are connected in series via a tunnel diode using n-InGaAs and p-GaAsSb. For improving the growth process and, thus, improving the cell performance the InGaAs/GaAsSb hetero interface was studied with low energy electron diffraction (LEED) and x-ray photoemission spectroscopy (XPS). Secondly, the growth conditions for the GaAsSb/InP hetero interface were investigated. First measurements of the low band gap tandem solar cells are shown. The low band gap tandem structure has been designed for operation below a high band gap tandem cell (GaAs).