The CdO:F samples have been deposited onto microscope glass substrates at 250 degrees C by ultrasonic spray pyrolysis method. With the incorporation of fluorine into CdO, the direct optical transition has shifted towards the shorter wavelengths, and the transparency of the material has increased at a given wavelength above the fundamental absorption edge. The shift in the absorption edge is explained by means of the Moss-Burstein effect, which is also supported with the results of the current-voltage characteristics. Here, a correlation has been established between the band broadening and the increase in conductivity due to the increase in carrier density. (C) 2007 Elsevier B.V. All rights reserved.