非晶N:GeSb薄膜的光致晶化及其相干声子谱表征

利用对微结构变化非常灵敏的相干声子光谱技术研究了非晶N:GeSb薄膜的光致相变特征。发现当激光辐照能流达到某个阈值时,出现了一个新的声子模,表明相变的发生。同时,退火晶化的N:GeSb薄膜也出现此新的声子模,表明激光照射的确导致了薄膜的晶化。相干光学声子谱的抽运能量密度依赖实验结果表明光致晶化的N:GeSb薄膜的相干光学声子的寿命和频率均随抽运能量密度增加而减小,与晶体中的依赖关系一致。结果表明N:GeSb薄膜的光致晶化质量较好,具有相变光存储应用潜力。

Femtosecond Laser irradiated Crystallization of Amorphous N:GeSb Film and Its in-Situ Characterization by Coherent Phonon Spectroscopy

Laser irradiation induced phase change of a new amorphous N:GeSb film is studied by coherent phonon spectroscopy, which is very sensitive to its microstructure. It is found that a new coherent optical phonon(COP) occurs as laser irradiation fluence reaches some threshold, implying laser-induced phase change emerged. Meanwhile, this new phonon also occurs in annealed crystallized N:GeSb film, which proves that the laser irradiation does lead to the crystallization of the N:GeSb film. Pump fluence dependence of COP dynamics of laser-induced crystallized N:GeSb film shows that the frequency and life time of COP decrease as pump energy density increases, which is in accordance with the annealed crystallized N:GeSb film. So it implies the high crystalline quality of the laser-induced phase-change film and the potential application of N:GeSb films in optical phase change memory.