High performance ultrathin GaAs solar cells

Epitaxially grown III–V compound semiconductors, such as gallium arsenide (GaAs), can provide superior photovoltaic (PV) performance due to many attractive material properties. However, the high cost of growing device-quality epitaxial materials has prevented their widespread adoption in terrestrial applications. In this regard, decreasing thicknesses of constituent epitaxial materials without compromising their photovoltaic performance is one of conceptually viable means to lower the cost. Here we present a type of thin film GaAs PV system with drastically reduced active layer thickness (∼200 nm), where dielectric periodic nanostructures and a metallic reflective element are heterogeneously integrated on the front- and back-surfaces of solar cells for nanophotonic light management to enhance the absorption and photovoltaic performance of ultrathin GaAs solar cells.