Annealing effect in a nitrogen atmosphere on structural and optical properties of In 2 Te 5 thin films

In2Te5 films were deposited by the magnetron sputtering method. The structural properties of both the as-deposited and annealed films have been studied respectively by Xray diffractometer and Raman spectrometer. As a result, the formation of the Te-Te bond was observed in Raman spectra of the film sample annealed at 400 degrees C. A spectroscopic ellipsometer was employed to measure the optical constants of the films. The optical band gap of the films varies with the annealing temperatures, which is attributed to the Burstein-Moss effect. In the meantime, the nonlinear optical characterization of the films was investigated by the open-aperture Z-scan technique, and it shows an apparent reverse saturation absorption. The effect of the nonlinear absorption coefficient should be related with the unsaturated defects and free carrier absorption. (C) 2017 Optical Society of America