Low-cost III–V solar cells grown by hydride vapor-phase epitaxy

The high epitaxial cost of high-efficiency III-V photovoltaic devices has limited these cells to niche markets. In this work, we demonstrate hydride vapor-phase epitaxy (HVPE) growth of III-V materials as a low-cost, high-throughput alternative to conventional metal-organic vapor-phase epitaxy (MOVPE). A brand new, custom-built HVPE reactor was used to obtain high-quality GaAs films at growth rates as high as 1.5 μm/min (90 μm/h). Near-ideal Hall mobilities for both n- and p-type carriers are demonstrated. Preliminary GaAs p-n junctions with unpassivated surfaces show significant rectifying behavior and excellent carrier collection, open-circuit voltage as high as 0.95 V, and fill factors of 86% under AM1.5G illumination. These results show the viability of HVPE for the growth of high-quality III-V devices at significantly lower costs.