Flexible and lightweight epitaxial lift-off GaAs multi-junction solar cells for portable power and UAV applications

Epitaxial lift-off (ELO) is a process technology that can enable substantial performance enhancement and cost reduction for epitaxially grown III–V devices. [1]–[4] In particular, GaAs-based inverted metamorphic multijunction (IMM) solar cells are an attractive technology that provides flexible, light-weight and high-efficiency solar panels for portable-power and unmanned aerial vehicle (UAV) applications. ELO is a process that involves selectively etching a “release” layer to detach the epitaxially grown functional III–V material from the substrate on which it is grown. The flexible ELO solar cell device layers are temporarily mounted on rigid carriers for standard, high-volume semiconductor processing methods, followed by release and integration into flexible panel formats.