Fabrication and Characterization of ZnO Nanoneedles Based Field Emission Device

摘要

This paper reports the facile non-catalytic growth of well-crystalline ZnO nanoneedles on silicon substrate by thermal evaporation process. The as-grown nanoneedles were characterized in detail in terms of their morphological, compositional, structural and optical properties using several techniques. The detailed morphological characterizations confirmed that the grown material possess needle-shaped morphologies which are grown in high density over the whole substrate surface. The observed compositional and structural properties confirmed that the grown nanoneedles are pure ZnO and possess well-crystallinity and wurtzite hexagonal phase. The presence of a sharp and strong UV emission in the room-temperature PL spectrum confirmed that the grown nanoneedles possess good optical properties. Finally, field emission properties of as-grown nanoneedles was examined. The observed turn-on field of 2.5 V/mu m at the current density of 0.051 mA/cm(2). The calculated field enhancement factor 'beta', from the F-N plot, was found to be 3111.