摘要：Hyd.ogenated.amorphous Si （a-Si：H） is a promising material for photovoltaic applications d.e to its low cost, high abund.nce, long lifetime, and.non-toxicity. We d.monstrate a d.vice d.signed.to investigate the effect of nanostructured.back reflectors on quantum efficiency in photovoltaic d.vices. We ad.pt a superstrate configuration so that we may use conventional ind.strial 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 stud.ed.the relation between nanostructure size and.photocurrent generation. The gain/loss transition at short wavelengths showed.red.shifts with d.creasing nanostructure scale. In the infrared.region the nanostructured.back reflector shows large photocurrent enhancement with a mod.fied.feature scale. This d.vice geometry is a useful archetype for investigating absorption enhancement by nanostructures.