This capability makes available experts in the design and growth of complex high-performance III-V semiconductor epitaxial structures and optoelectronic devices, combined with the metal-organic vapor-phase epitaxy (MOVPE) tools on which the experts will fabricate the devices for the end user. The experts have developed a range of devices for photovoltaic and PEC application, including inverted metamorphic four-junction solar cells with record 46% efficiency, and inverted metamorphic two-junction structures forming the foundation of PEC devices with over 15% solar-to-hydrogen efficiency. The experts are accomplished in the implementation of device features including metamorphic layers; tunnel junctions; photovoltaic junctions; and substrate removal. The MOVPE tool instrumentation includes in-situ wafer stress sensing, which is critical for the development of high-performance metamorphic structures. The tools are configured with sources for the growth of arsenide- and phosphide-based semiconductors over a wide range of compositions and dopings; materials include Ga, In, Al, As, P, Sb, N, Zn, Se, Si, C. Structure growth is highly automated; structures of more than one hundred distinct layers are routinely grown. Through the collaborative concept-to-device development process working with the Capability's experts, users would be able to rapidly go from concept of a device structure to its realization without having to acquire the requisite deep expertise in III-V materials and device growth.