Superior radiation and dislocation tolerance of IMM space solar cells

In this work we have evaluated thickness dependent efficiency of IMM solar cells as a function of radiation doses and dislocations and band gap of the bottom metamorphic InGaAs subcell. It is shown that for moderate to high doses of radiation, very high EOL efficiencies can be afforded with substantially higher dislocation densities than those commonly perceived as acceptable for IMM devices. i.e even in the presence of dislocation densities as large as 10⁷cm², for typical 10¹⁵cm² 1MeV electron fluence a remaining power factor of >;85% (ηEOL~29%) can be reached by a careful selection of InGaAs band gap. Finally these finding could in turn be used to simplify manufacturing (thinner graded buffers) or/and increase yield for IMM space cells.