Near-ideal photodiodes from sintered gold nanoparticle films on methyl-terminated Si(111) surfaces

We report photocurrent-voltage data for improved n-Si/metal devices using CH₃-terminated n-Si(111) and Au nanoparticles (NPs). CH₃-terminated Si(111) surfaces maintain good electronic properties throughout device assembly, while the use of Au NPs as precursors to metal films circumvents the standard issues associated with interfacial reactivity of metals in Schottky barrier formation. Such devices demonstrate excellent photovoltaic properties, with photovoltages that approach the maximum values predicted for photodiodes that are limited by Si bulk diffusion/recombination processes rather than interfacial processes. These devices are compared to standard n-Si/Au devices made via thermally evaporated Au films which are well-known to be limited by junction-based recombination.