缓冲气体对激光烧蚀制备掺 Er 纳米 Si 晶薄膜结构特性的影响

采用 XeCl 脉冲准分子激光器,保持激光脉冲比为1:3,分时烧蚀Er靶和高阻抗单晶Si靶,在10 Pa的Ne气环境下沉积了掺Er非晶Si薄膜. 在氮气保护下,分别在1 000℃,1 050 ℃和1 100℃温度下进行30 min热退火处理. 对所得样品的Raman谱测量证实,随着退火温度的升高,薄膜的晶化程度提高;利用扫描电子显微镜观测了所制备的掺Er纳米Si晶薄膜的表面形貌,并与相同实验参数、真空环境下烧蚀并经热退火的结果进行了比较. 结果表明,Ne气的引入,使形成轮廓明显的掺Er纳米Si晶粒的退火温度降低,有利于尺寸均匀的晶粒的形成.

Influence of the Ambient Gas on the Microstructural Properties of Er-doped Nanocrystalline Si Films Fabricated by Pulsed Laser Ablation

Ablating alternately Er and Si targets with the pulse-number-ratio of 1:3 by a XeCl excimer laser,Er-doped amorphous Si films were prepared in Ne gas of 10 Pa or vacuum.The as-formed films,being annealed for 30 minutes at constant temperature of 1 000 ℃,1 050 ℃ or 1 100 ℃ in N_2 gas,were converted into Er-doped nanocrystalline Si films,which were confirmed by the position of Raman spectra peak.Scanning electron microscopy images show that Ne gas,compared to vacuum,induces more uniform-sized Er-doped nanocrystalline Si nanoparticles and lower crystallizing temperature.