Field Emission from TiO_2/Ti Nanotube Array Films Modifiedwith Carbon Nanotubes

摘要

Well-aligned TiO_2/Ti nanotube array films were synthesized by using anodic oxidation of titaniumin 0.5-wt% HF and were modified with carbon nanotubes (CNTs) assembled by using catalyzedchemical vapor deposition (CVD) at 650 °C. The morphology and the quality of the films wereassessed with field emission scanning electron microscopy and Raman spectrometry (325 nm). Thefield emission characteristics of such TiO_2/Ti nanostructures were investigated before and afterbeing modified with CNTs. The results show that the TiO_2/Ti nanotube arrays possess a moderateturn-on electric field of 7.4 V/μm, a field emission current density of 2.7 mA/cm~2at 23 V/μm. It isnoteworthy that the turn-on field of the TiO_2/Ti nanotube arrays modified with CNTs is decreasedsignificantly to 1.3 V/μm, and the emission current density is increased to 10 mA/cm~2at 5.6 V/μm.This novel structure shows high emission efficiency as a field emitter.