Pulsed laser deposition of graphite in air and in vacuum for field emission studies

A comparative study of pulsed laser deposition (PLD) based carbon films when deposited either, in atmospheric air, or under vacuum, has been performed. Micro-structural characterization of deposited films was carried out employing X-ray diffraction and Raman spectroscopic techniques. While, nanocrystalline graphite phase was observed in carbon films deposited in air, PLD films deposited under vacuum were largely amorphous in nature. Field emission (FE) properties of films deposited in air and under vacuum were investigated. Superior FE behavior characterized by a lower turn-on field (2.72 V/μm) and high field enhancement factor (∼2580) was observed for PLD films deposited in air. This improved field emission demonstrated by carbon films deposited via PLD in air can be attributed to presence of nanocrystalline graphite aggregates in such carbon films and local field enhancement near the sp2 sites. Our results therefore, establish PLD in air as a simple technique for deposition of carbon films having good field emission capability.