Silicene/Silicene Oxide Nanosheets for Broadband Photodetectors

Nanosheets of silicene, a 2D material made of silicon atoms, have great potential for use in next-generation electronic and optoelectronic devices due to their unique properties. However, issues in the large-scale production of silicene nanosheets and in their degradation still present challenges for these applications. Here, we report a method to obtain large quantities of single to few-layer thick silicene/silicene oxide (“Si nanosheets”) from calcium disilicide (CaSi2). We also show that the silicene nanosheets experience oxidation in air and are highly oxidized after 12 weeks of storage. Density functional theory studies were performed and provide a detailed understanding of this oxidation. Silicene/silicene oxide nanosheet-based photodetector devices were also fabricated for the first time. They show a broadband response in the visible spectral range with outstanding responsivity (14.3 A/W), detectivity (3 × 1010 Jones), and external quantum efficiency (44.6%), demonstrating the promising applications of this material for optoelectronic devices.