Characterization and enhanced field emission properties of carbon nanotube bundle arrays coated with N-doped nanocrystalline anatase TiO2

Anatase TiO2 nanocrystals (NCs) were deposited onto patterned carbon nanotube (CNT) bundle arrays to form a TiO2/CNT composite using metal organic chemical vapor deposition (MOCVD) using titanium-tetraisopropoxide (Ti(OC3H7)(4)) as a source reagent. The N-doped TiO2/CNT composite was then fabricated using nitrogen plasma treatment. The structural and spectroscopic properties of TiO2/CNT composites were characterized by field-emission scanning electron microscopy, micro-Raman spectroscopy and X-ray photoelectron spectroscopy. The combined geometrical structure and low electron affinity effects of N-doped TiO2 led to a low turn-on field of 1.0 V mu m(-1) at a current density of 10 mu A cm(-2), a low threshold field of 1.9 V mu m(-1) at a current density of 1 mA cm(-2), a high field enhancement factor of 3.0 x 10(3), and long-term stability for the N-doped TiO2/CNT composite. The results revealed that the N-doped TiO2/CNT composite can be a potential candidate for field emission devices. (C) 2013 Elsevier B.V. All rights reserved.