III-V Semiconductor Epi-Structure and Device Design and Fabrication


National Renewable Energy Laboratory (NREL)

Capability Expert

Myles Steiner


Material Synthesis
Process and Manufacturing Scale-Up

Node Readiness Category

1: Photoelectrochemical (PEC)


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.

Capability Bounds‎

Epi-structures are grown on up to two-inch-diameter wafers.

Unique Aspects‎

This is the only capability within the national lab system with demonstrated capability for development and fabrication of ultrahigh efficiency photovoltaic devices with efficiencies of 46%. This capability's development and fabrication of inverted metamorphic two-junction PEC devices is similarly unique.


Device structures are designed by the Capability Operations Scientists in close collaboration with the user to meet the user's needs, and fabricated by the Capability Operations Technicians. The capability is well-subscribed and calibrated by current stakeholders. Effective prioritization makes this equipment moderately available for HydroGEN user experiments that are deemed to align with this capability's broader mission.


This capability would allow users to go very rapidly from concept to realization of complex high-efficiency PEC structures, in support of HydroGEN goals.


Photograph of one of the Capability's two MOVPE growth tools. The tools incorporate a large variety of materials sources as noted above, and are built to be flexible and reconfigurable.


1. 2. France et al, "Design Flexibility of Ultra-High Efficiency 4-Junction Inverted Metamorphic Solar Cells," IEEE J. Photovolt. v. 6, pp. 578-583 (2016).