Formation of tunable diamond micro- and nanopillars for field effect enhancement applications

We developed a process for the fabrication of tunable single crystal diamond micro- and nanopillars , with tip widths ranging from 40 to 460 nm, densities ranging from 0.5 to 53.5 pillars/μm 2 , and heights greater than 4.5 μm. A self-assembled Au nanodot ensemble etch mask was formed from an annealed Au thin film . The nanodot diameter and density can be tuned using the initial film thickness. The pillars were etched from the nanodot mask using an RIE O 2 plasma, which has infinite selectivity for the diamond when applied at low RF powers (50 W). Finally, the pillars can be sharpened to ∼40 nm tip widths by annealing in air at 650 °C. These pillars can be used for applications such as field effect enhancement of diamond photocathode devices, enhancement of optical emission from N-V centers, and antireflective coatings. • Diamond nanopillar geometry can be tuned by modulating Au etch mask thickness and applying plasma and thermal oxygen etching. • Au film thickness can be modulated to tune the density and size of micropillars etched into diamond. • Diamond pillars can be sharpened in oxygen down to 40 nm wide at the tip by thermal etching. • Low etching powers produces a near infinite selectivity between diamond and a Au etch mask.