Development of 6-inch GaAs solar cells grown by single-chamber hydride vapor phase epitaxy

In III-V solar cells, reducing manufacturing costs is essential to further expand the applications. Hydride vapor phase epitaxy (HVPE) has gained attention due to its fast growth technique using inexpensive group III precursors. Higher throughput and larger wafer loading are essential to reduce growth costs. However, increasing the size of HVPE equipment has difficulty in terms of temperature distribution, uniformity of gas supply, and controllability of heteroepitaxy. We have developed a high-throughput 6-inch HVPE system for the first time. Although challenges remain with heteroepitaxy, we have demonstrated a GaAs single-junction solar cell grown with GaInP window layer with a conversion efficiency of 13.2%. Furthermore, the open-circuit voltage of the cell was found to be nearly constant at 0.92 V regardless of the growth rate up to 298 µm/h.