Multiphoton photoemission of gold nanopillars fabricated by carbon nanotube templates

High-aspect ratio metallic nanopillars are promising as electron emitters in frequency ranges of terahertz and higher. However, producing nanopillars with aspect ratio of more than a factor of 10 by lithographic methods is still a challenge. Here, the authors report the fabrication of Au nanopillars using carbon nanotube forests as templates and a study on their near infrared photocurrent characterization. The pillars had the diameter of 100 nm and the aspect ratio up to 28. The authors observed an increase in the photocurrent from Au nanopillars with the increase in the nanopillar height. The observed photocurrent is compatible with the multiphoton photoemission and is uncorrelated to the pillar density. The results indicate that our proposed method is promising to produce electron sources for high frequency vacuum nanoelectronic devices.