We report the field-assisted H 2 O etching that enabled us to fabricate nano-tips from polycrystalline <1 1 0> oriented tungsten wires at room temperature. We optimized the sharpening procedure in order to obtain field emissions (FEs) with high collimation. The typical tip apex was composed of a large base and a nano-protrusion with a radius of curvature less than 3.5 . The narrowest opening angle (full width at half maximum) of the FE was 4.3° at 150 pA. We prepared two types of tips using two different applied bias voltages during the H 2 O etching. The electron microscope images and the analysis of Fowler-Nordheim (FN) plots revealed that the sizes of the individual bases depended on the fixed bias voltages during the H 2 O etching and affected their FE properties. In addition, we could confirm that the FE current from the nano-tip was more stable than that of the normal tip.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Physics and Astronomy(all)
- Surfaces and Interfaces
- Surfaces, Coatings and Films