Thermal, structural and optical properties of NiOx thin films deposited by reactive dc-magnetron sputtering

The NiOx thin films were deposited by reactive dc-magnetron sputtering from a nickel metal target in Ar + O-2 with the relative O-2 content 5%. The as-deposited NiOx, thin films could represent a two-component system comprising crystalline NiO particles dispersed in an amorphous Ni2O3. Decomposition temperature of the as-deposited NiO, thin films was at about 263 degrees C. After annealed at 400 degrees C for 30 min in air, the surface morphology of the films became very rough due to the decomposition of the Ni2O3, leading to the changes of the optical properties of the NiO, thin films. The reflectivity of the films annealed at 400 degrees C was lower than that of the as-deposited one and the optical contrast was 52% at 405 nm. (c) 2006 Elsevier B.V. All rights reserved.

Structural change of laser-irradiated Ge2Sb2Te5 films studied by electrical property measurement

Sheet resistance of laser-irradiated Ge2Sb2Te5 thin films prepared by magnetron sputtering was measured by the four-point probe method. With increasing laser power the sheet resistance undergoes an abrupt drop from 10(7) to 10(3) Omega/square at about 580 mW. The abrupt drop in resistance is due to the structural change from amorphous to crystalline state as revealed by X-ray diffraction (XRD) study of the samples around the abrupt change point. Crystallized dots were also formed in the amorphous Ge2Sb2Te5 films by focused short pulse laser-irradiated, the resistivities at the crystallized dots and the non-crystallized area are 3.375 x 10(-3) and 2.725 Omega m, sheet resistance is 3.37 x 10(4) and 2.725 x 10(7) Omega/square respectively, deduced from the I-V Curves that is obtained by conductive atomic force microscope (C-AFM). (C) 2008 Elsevier B.V. All rights reserved.