Carbon nanotube-tungsten nanowire hierarchical structure for augmented field emission performance

An increasing number of emitting sites and higher aspect ratios are constantly being added to field emission systems to further improve their properties. Such an ever-growing demand has thrown light on the development of hierarchical field emitters. Tungsten (W) and carbon nanotubes (CNT) have been commonly reported as potential field emitter materials. The present work focused on constructing a hierarchical field emitter structure of CNTs/W nanowires. The structural characterization has been studied using field emission scanning electron microscopy, high-resolution transmission electron microscopy, and x-ray diffraction to confirm the hierarchical structure formation. The carbon nanotube-tungsten nanowire hierarchical structural emitters have demonstrated high current density (31.5 mA cm^-2), exceptionally low turn-on field (0.068 Vμm^-1), and emission stability for more than 152 h. This excellent performance could be related to the formation of a strong as well as the electrically favourable interface between tungsten nanowires and CNTs.