Fu, JingShen, XiangXu, YinshengWang, GuoxiangNie, QiuhuaLin, ChangguiDai, ShixunXu, TiefengWang, Rongping2015-12-130167-577Xhttp://hdl.handle.net/1885/71044Ge 2Sb 2Te 5 films were locally crystallized by a tightly focused laser beam and the structural evolution was studied by Raman scatting. The marks recorded by a broad range of laser power were studied by optical microscope. Raman spectra of films with irradiation power of 0.1 mW and 1 mW were consistent with those of films annealed at 140°C and 400°C, respectively. It reveals that both the cubic and hexagonal crystalline phases have been achieved under the irradiation of 488 nm laser in amorphous Ge 2Sb 2Te 5 films. Specifically, the appearance of a new band of ∼141 cm -1 in films with irradiation power larger than 1.25 mW confirms that the over-irradiation causes the segregation of Te crystalline phase in films.Keywords: Crystalline phase; Hexagonal crystalline; Irradiation power; Laser power; Optical microscopes; Raman; Structural evolution; Tightly focused laser beam; XRD; Germanium; Irradiation; Microstructure; Phase transitions; Amorphous films Microstructure; Phase transformation; Raman; XRD201210.1016/j.matlet.2012.08.0512016-02-24