The ion beam sputtering technique was employed to prepare diamondlike carbon (DLC) films at nearly room temperature. Simultaneous ion beam bombardment during film growth was also conducted in order to study the bombardment effects. Raman spectroscopy was used to evaluate the structure property. The sp(3) fraction was found to strongly depend on the bombarding ion energy, giving a highly sp(3) bonded DLC at ion beam bombarding energies around 800 eV. The emission characteristics of these amorphous DEC films were compared. Field emission from DLC deposited with higher bombarding energies exhibit enhanced emission properties. High electron emission current, about 370 mu A over a 1 cm(2) cathode area, was obtained with an electric field of 18.5 V/mu m. The mechanism for electron emission from DLC films is also discussed.