飞秒激光辐照Ge_2Sb_2Te_5相变薄膜的拉曼光谱研究

Raman scattering study on Ge_2Sb_2Te_5 phase-change films irradiated by femtosecond laser

室温下,采用磁控溅射镀膜系统在Si(100)基片上制备了Ge2Sb2Te5(GST)薄膜样品.对分别经过不同能量密度的飞秒激光辐照及经退火炉200℃退火处理的样品,进行拉曼光谱测试,通过分析其拉曼光谱峰位的变化来研究GST薄膜从非晶态到晶态转变的相变过程.随着辐照激光能量密度的增加,薄膜的拉曼峰位出现了定向移动.经200℃退火样品的拉曼谱与经24mJ/cm2飞秒激光辐照的样品拉曼谱相似,表明在一定条件下,超快激光光致相变与温控相变具有相似的效果.

Ge2Sb2Te5（GST） alloy films on Si（100） substrate was prepared by a magnetron sputtering system at room temperature.The samples irradiated by femtosecond laser with different energy or annealed at 200℃ in an annealing furnace were studied by Raman spectra measurement,respectively.The dynamic transformation from amorphous state to crystalline state of GST films was analyzed by the changes of their Raman spectra.With the increasing of the laser intensity irradiated on the samples,regular shifts of their Raman peaks were found.Furthermore,the Raman spectra of the samples annealed at 200℃ are similar to that of irradiated by femtosecond laser with intensity of 24 mJ/cm2.The phase change caused by ultrafast laser irradiation is similar to the thermal treatment in this case.