gamma- and alpha-Al2O3 films were prepared by chemical vapor deposition using CO2, Nd:YAG, and InGaAs lasers to investigate the effects of varying the laser wavelength and deposition conditions on the phase composition and microstructure. The CO2 laser was found to mostly produce alpha-Al2O3 films, whereas the Nd:YAG and InGaAs lasers produced gamma-Al2O3 films when used at a high total pressure. gamma-Al2O3 films had a cauliflower-like structure, while the alpha-Al2O3 films had a dense and columnar structure. Of the three lasers, it was the Nd:YAG laser that interacted most with intermediate gas species. This promoted gamma-Al2O3 nucleation in the gas phase at high total pressure, which explains the cauliflower-like structure of nanoparticles observed. (C) 2015 Elsevier B.V. All rights reserved.