In this paper, we investigate tandem amorphous/microcrystalline silicon solar cells with asymmetric intermediate reflectors grown in the n-i-p substrate configuration. We compare different types of substrates with respect to their light-trapping properties as well as their influence on the growth of single-junction microcrystalline cells. Our most promising back reflector combines a textured zinc oxide film grown by low-pressure chemical vapor deposition, a silver film for reflection, and a zinc oxide buffer layer. Grown on this substrate, microcrystalline cells exhibit excellent response in the infrared while keeping high open-circuit voltage and fill factor, leading to efficiencies of up to 10.0%. After optimizing the morphology of the asymmetric intermediate reflector, we achieve an n-i-p micromorph solar cell stabilized efficiency of 11.6%, using 270 nm and 1.7 mu m of silicon for the absorber layer of the amorphous top cell and the microcrystalline bottom cell, respectively. Using this original device architecture, we reach efficiencies close to those of state-of-the-art n-i-p and p-i-n micromorph devices, demonstrating a promising route to deposit high-efficiency thin-film silicon solar cells on opaque substrates. (C) 2013 Elsevier B.V. All rights reserved.