Very high peak current CBE grown InGaAs tunnel junction for InP/InGaAs tandem cells fabricated on InP, GaAs, and Si substrates

For the first time high quality In/sub 0.53/Ga/sub 0.47/As tunnel junctions were grown at relatively low temperatures (450/spl deg/C to 530/spl deg/C) using chemical beam epitaxy (CBE). p/sup ++n/sup ++/ In/sub 0.53/Ga/sub 0.47/As tunnel junctions were realized on InP, GaAs, and GaAs/Si substrates. Homoepitaxial devices (grown on InP) exhibit excellent room temperature I-V characteristics. Peak current density exceeding 1000 A.cm/sup -2/ with specific resistivities in the range of 10/sup -4/ /spl Omega/.cm/sup 2/ were obtained. Heteroepitaxial devices fabricated on GaAs (4% lattice mismatch) and Si (8% lattice mismatch) exhibit peak current densities similar to their homoepitaxial counterparts. Finally no degradation of the tunnel device performance is observed after the subsequent CBE growth of state of the art InP solar cells.<
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