Ultrathin, microscale epitaxial compound semiconductor solar cells

Abstract

Compound semiconductors offer significant advantages over silicon in photovoltaics due to their direct bandgaps, ability to form multijunction solar cells, as well as superior radiation hardness. However, costs for growth and integration of these materials have been prohibitively high, thereby limiting their large-scale implementation in terrestrial photovoltaics. Here we review materials growth and fabrication strategies that were recently developed to address many of these challenges by employing device-quality, multilayer epitaxial assemblies of compound semiconductors in the manner that enables sequential release of respective functional layers as well as reuse of the growth substrate. This new approach combined with techniques of micro-transfer printing provides a practical and cost-effective route to implement high quality compound semiconductors in terrestrial photovoltaics but also opens up new application possibilities and modes of use that have not been possible with conventional technologies.