{Reference Type}: Journal Article {Title}: Effects of Nanostructured Back Reflectors on the External Quantum Efficiency in Thin Film Solar Cells {Author}: Hsu, Chingmei; Burkhard, George F.; McGehee, Michael D.; Yi, Cui {Journal}: Nano Research {ISBN/ISSN}: 1998-0124 {Year}: 2011 {Volume}: 4 {Issue}: 2 {Pages}: 153-158 {DOI}: 10.1007/s12274-010-0064-y {Keywords}: scattering {Keywords}: Solar cells {Keywords}: solar energy {Keywords}: amorphous silicon {Keywords}: back reflector {Abstract}: Hydrogenated amorphous Si (α-Si: H) is a promising material for photovoltaic applications due to its low cost, high abundance, long lifetime, and non-toxicity. We demonstrate a device designed to investigate the effect of nanostructured back reflectors on quantum efficiency in photovoltaic devices. We adopt a superstrate configuration so that we may use conventional industrial light trapping strategies for thin film solar cells as a reference for comparison. We controlled the nanostructure parameters via a wafer-scale self-assembly technique and systematically studied the relation between nanostructure size and photocurrent generation. The gain/loss transition at short wavelengths showed red-shifts with decreasing nanostructure scale. In the infrared region the nanostructured back reflector shows large photocurrent enhancement with a modified feature scale. This device geometry is a useful archetype for investigating absorption enhancement by nanostructures. {URL}: https://www.sciopen.com/article/10.1007/s12274-010-0064-y {Language}: en