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 107 to 103 Ω/□ 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 × 10−3 and 2.725 Ω m, sheet resistance is 3.37 × 104 and 2.725 × 107 Ω/□ respectively, deduced from the I–V curves that is obtained by conductive atomic force microscope (C-AFM).