Abstract
This paper reports the aligned growth, characterization and field emission device applications of well-crystalline ZnO nanowires. The aligned ZnO nanowires were grown on silicon substrate without using any templates or seed layer by a simple and facile thermal evaporation process using metallic zinc powder in presence of oxygen. The prepared aligned ZnO nanowires were characterized by several techniques such as field emission scanning electron microscopy attached with energy dispersive spectroscopy, X-ray diffraction, photoluminescence and Raman-scattering spectroscopy. The detailed morphological studies confirmed the high-density growth of aligned ZnO nanowires on silicon substrate. The room-temperature photoluminescence (PL) spectrum of aligned ZnO nanowires exhibited a sharp and strong UV emission with suppressed deep level emission revealed the good optical properties of the grown nanowires. Finally, the grown aligned ZnO nanowires on silicon substrate were used for field emission device applications. The field emission analysis for aligned ZnO nanowires demonstrates a turn-on field of 4.2 V/mu m while the observed threshold field for the fabricated device was 5.8 V/mu m. The calculated field enhancement factor 'beta', from the F-N plot, was found to be similar to 2504.