High-density uniformly aligned silicon nanotip arrays and their enhanced field emission characteristics

High-density (∼108/cm2), uniformly aligned silicon nanotip arrays are synthesized by a plasma-assisted hot-filament chemical vapor deposition process using mixed gases composed of hydrogen, nitrogen and methane. The silicon nanotips grow along 〈112〉, and are coated in situ with a ∼3 nm thick amorphous carbon film by increasing the methane concentration in the source gases. In comparison to the uncoated silicon nanotips arrays, the coated tips have enhanced field emission properties with a turn-on field of 1.6 V/μm (for 10 μA/cm2) and threshold field of 3 V/μm (for 10 mA/cm2), suggesting their potential applications for flat panel displays.