MicroLink Devices

MicroLink Devices is a US-based developer and manufacturer of ultra-lightweight flexible III-V multi-junction solar cells using Epitaxial Lift-Off (ELO) technology — a proprietary process that grows high-efficiency III-V semiconductor solar cell stacks on a reusable substrate wafer and then mechanically releases the sub-30 micrometer thin film, yielding cells with specific power exceeding 3,000 W/kg — more than five times lighter than conventional germanium-substrate solar cells used on most spacecraft.

Conventional space solar cells are grown on a germanium (Ge) wafer that serves as both substrate and bottom junction, resulting in cell thickness of 140-180 micrometers and specific power (power output per unit mass) typically in the range of 500-800 W/kg. MicroLink's ELO process grows the same high-efficiency triple-junction AlInGaP / InGaAs / Ge (or four-junction) photovoltaic stack on a GaAs substrate, then chemically separates (lifts off) the sub-30 micrometer active layers using a release etch — leaving the substrate intact and reusable for subsequent cell growths, dramatically reducing material cost — while the thin-film cell itself weighs a fraction of a conventional monolithic cell.

The resulting flexible, lightweight cells achieve 37-38% beginning-of-life efficiency under AM0 in the best four-junction configurations, while the mass advantage is transformative for power-mass-constrained applications: solar array panels using MicroLink cells can deliver the same power in significantly less mass, or equivalently larger deployed area and power in the same mass budget. This is particularly valuable for small satellites and CubeSats where mass is severely limited, stratospheric pseudo-satellite (HAPS) aircraft like AeroVironment's Sunglider that need maximum power per kilogram for perpetual solar-powered flight, and lunar surface rovers operating far from electrical infrastructure.

The reusable substrate aspect of ELO is also economically significant: if GaAs wafer costs can be amortized across multiple cell growth cycles (MicroLink has demonstrated wafer reuse for 20+ cycles), the cost per watt of III-V solar cells — historically 50-100x more expensive than silicon — could approach price points accessible for broader terrestrial concentrating PV and specialized applications.

MicroLink competes with conventional space solar cell manufacturers Spectrolab, SolAero/Rocket Lab, and AZUR SPACE in the satellite power market, while occupying a distinct niche in the ultra-lightweight flexible cell segment alongside Emcore's thin-film offerings.