科研之友
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摘要
Semiconductor nanomaterials have recently fueled numerous photonic scientific fields. Arrays of nanopillars (NPs) have been examined by the photovoltaic (PV) community as highly efficient solar absorbers, with potential material/cost reductions compared to planar architectures. Despite modeled predictions, experimental efficiencies are limited by surface recombination and poor light management, once integrated in a practical PV device. In this Letter, we correlate optoelectronic modeling with experimental results for direct-bandgap arrays of core-multishell GaAs NPs grown by selective area, catalyst-free epitaxy and capped by epitaxial window layers, with efficiencies of 7.43%. Electrically, improved open-circuit voltages are yet partly affected by residual surface state density after epitaxial passivation. Optically, dome-shaped indium-tin-oxide (ITO) top electrode functions as a two-dimensional (2-D) periodic array of subwavelength lenses that focus the local density of optical states within the NP active volume. These devices provide a path to high-efficiency NP-based PVs by synergistically controlling the heteroepitaxy and light management of the final structure.
- 出版日期2013-4
