Ultrashort pulsed laser deposition of ITO thin films

摘要

Pulsed Laser Deposition of indium tin oxide in the femtosecond regime has been performed in our laboratory. Plume diagnostics has been carried out by means of a fast Intensified Coupled Charge Device (ICCD) camera. Optical emission spectroscopy has been applied to characterize the transient species produced in the femtosecond regime. The time evolution of emission lines has been discussed and compared with that obtained for nanosecond regime. The films, deposited on glass substrates, has been analysed by scanning electron microscopy, energy dispersive x ray analysis, x ray photoelectron spectroscopy and x ray diffraction. The results obtained from femtosecond ablation show that the processes in the short pulse regimes are very different from the nanosecond one. In particular the plume angular distribution shows a characteristic high cosine exponent and the composition of the deposits is completely stoichiometric and independent from the laser fluence, even if to obtain crystalline films a substrate temperature of 600℃ is needed. Preliminary data indicate that the deposited films are suitable for gas sensor applications.