Multi-walled carbon nanotubes (MWNTs) were synthesized by irradiating of a CO2 laser in continuous wave mode onto a boron-containing graphite target at room temperature. The pressure of Ar atmosphere was controlled in 50, 150, 400, or 760 Torr. The diameter of obtained MWNTs was in the range of 5-40 nm. The quantity and degree of graphitization of synthesized MWNTs increased with the Ar gas pressure. A large quantity of MWNTs with fine crystalline structure has been synthesized preferentially at the condition of 760 Torr. The MWNTs with the fine crystalinity indicated highly oxidative stability in O-2. We also found that a large area field emission device with MWNT cathodes indicated good beta value of 3.6 x 10(4) cm(-1), and sufficient reliability for long term operations over 150 h, suggesting promising application to field emission devices. (C) 2012 Elsevier B. V. All rights reserved.