Upright and Inverted Single-Junction GaAs Solar Cells Grown by Hydride Vapor Phase Epitaxy

Hydride vapor phase epitaxy (HVPE) is a low-cost alternative to conventional metal-organic vapor phase epitaxy (MOVPE) growth of III-V solar cells. In this work, we show continued improvement of the performance of HVPE-grown single-junction GaAs solar cells. We show over an order of magnitude improvement in the interface recombination velocity between GaAs and GaInP layers through the elimination of growth interrupts, leading to increased short-circuit current density and open-circuit voltage compared with cells with interrupts. One-sun conversion efficiencies as high as 20.6% were achieved with this improved growth process. Solar cells grown in an inverted configuration that were removed from the substrate showed nearly identical performance to on-wafer cells, demonstrating the viability of HVPE to be used together with conventional wafer reuse techniques for further cost reduction. These devices utilized multiple heterointerfaces, showing the potential of HVPE for the growth of complex and high-quality III-V devices.