Electroluminescence of atoms in a graphene nanogap

Here, we report light emission from single atoms bridging a graphene nanogap that emit bright visible light based on fluorescence of ionized atoms. Oxygen atoms in the gap shows a peak emission wavelength of 569 nm with a full width at half maximum (FWHM) of 208 nm. The energy states produced by these ionized oxygen atoms bridging carbon atoms in the gap also produce a large negative differential resistance (NDR) in the transport across the gap with the highest peak-to-valley current ratio (PVR = 45) and highest peak current density (similar to 90 kA/cm(2)) ever reported in a solid-state tunneling device. While tunneling transport has been previously observed in graphene nanogaps, the bridging of ionized oxygen observed here shows a low excess current, leading to the observed PVR. On the basis of the highly reproducible light emission and NDR from these structures, we demonstrate a 65,536-pixel light-emitting nanogap array.

Automated summary

This study reports on the emission of bright visible light from single atoms bridging a graphene nanogap, as well as the observation of a negative differential resistance. Ionized oxygen atoms, after bridging carbon atoms in the nanogap, produce a high peak-to-valley current ratio and peak current density, demonstrating highly reproducible light emission.