Amorphous GaAsl-xNx （a-GaAsl-xNx） thin films have been deposited at room temperature by a reactive magnetron sputtering technique on glass substrates with different sputtering pressures. The thickness, nitrogen content, carrier concentration and transmittance of the aseposited films were determined experimentally. The influence of sputtering pressure on the optical band gap, refractive index and dispersion parameters （Eo, Ed） has been investigated. An analysis of the absorption coefficient revealed a direct optical transition characterizing the asdeposited films. The refractive index dispersions of the as-deposited a-GaAsl-xNx films fitted well to the Cauchy dispersion relation and the Wemple model.
