Preparation of Chain-like Carbon Nano-tubes Film and Its Field Emission Properties

摘要

Chain-like Carbon Nano-tubes films have been synthesized by microwave plasma enhanced chemical vapor deposition (MWPECVD). The titanium-coated ceramic substrate was placed in a stainless steel reaction chamber of MPCVD system. Prior to deposition, The substrates were grinded with SiO_2 powder with Fe dopant . The mixture gas of methane (CH4) and hydrogen (H_2) was introduced into the chamber. The flow rates of CH_4/H_2 were controlled at 14/100 sccm by mass flower, respectively. The total pressure in the chamber was kept at 6.2kPa during the deposition. The microwave power of 1700w, worked at a frequency of 2450Mhz, was applied during deposition. The deposition time was only 1minute. The nano-structure of the deposited films was analyzed by SEM, TEM and Raman spectroscopy. The chain-like nano-tubes randomly distributed on the substrates. The nano-tubes are multi-wall with diameter of about 60 nm. The field electron emission characteristics of the Chain-like Carbon Nano-tubes films were measured under the vacuum of 10~(-5)Pa. The low turn-on field of 0.74V/μm and emission current density of 8.5mA/cm~2 at electric field 2.9V//μm were obtained. The mechanism of its field emission properties was also discussed.