Amorphous carbon (a-C) films were deposited on Si substrates by oxygen plasma-assisted pulsed laser deposition (oxygen PAPLD) technique and were compared with those deposited by PLD in oxygen gas. The film properties were characterized by spectroscopic ellipsometry and X-ray photoclectron spectroscopy. It was shown that the films obtained by the oxygen PAPLD at a substrate temperature, T-sub similar to 150 degrees C, were "diamond-like", while those by PLD in oxygen gas at T-sub = 550-625 degrees C were "graphite-like ". This difference could be explained by a high etching rate of sp(2) bond in a-C films in oxygen plasma. In the optical emission spectra obtained from carbon ablation plumes near substrate in the oxygen PAPLD, the strong emission bands of CO and CO+ were observed, which could be a proof of the etched molecules by atomic oxygen produced in oxygen plasma. (c) 2005 Elsevier B.V. All rights reserved.