Optimization of GaAs solar cell performance and growth efficiency at MOVPE growth rates of 100 mm/h
III-V devices outperform all other solar cells in terms of efficiency. However, the manufacturing of these cells is expensive and prevents their use in a number of applications, which would benefit from the high efficiency. A major contribution to the cost is the metal-organic vapor phase epitaxy process for the III-V compounds. Increasing growth rates and, hence, machine throughput, as well as the growth efficiency, are important steps toward reducing the cost of III-V solar cells. We demonstrate the growth of GaAs solar cells at extremely high growth rates of 100 mm/h and achieve a VOC of 1.028 V, a base diffusion length of 6.5 mm, and an efficiency of 23.6% under AM1.5g conditions. Furthermore, we show reactor adjustments leading to growth rates up to 140 mm/h and reach conditions where more than half of the Ga from the precursor is incorporated into the solar cell layers. The results are encouraging and demonstrate a pathway toward lower cost III-V solar cell manufacturing.