激光诱导生成锗纳米晶体量子点

Germanium quantum dots formed by oxidation of SiGe alloys

采用氧化和析出的方法在氧化硅中凝聚生成锗纳米晶体量子点结构。其形成的锗晶体团簇没有突出的棱角和支晶结构,锗晶体团簇的轮廓较圆混,故可以用球形量子点模型来模拟实际的锗晶体团簇。对比了在高温(800℃-1000℃)条件下和在低温(200℃-500℃)用激光照射条件下所生成的锗纳米晶体结构的PL 光谱和对应的锗纳米晶体团簇的尺寸分布。低温用激光照射条件下所生成的锗纳米晶体较小,其PL光谱出现蓝移。用量子点受限模型计算了锗纳米晶体团簇的能隙结构,用Monte Carlo方法模拟了PL光谱和对应的锗纳米晶体团簇的尺寸分布,分别与实验结果吻合较好。

We report the investigation on the oxidation behavior of Sil-xGex alloys （x=0.05, 0.15, and 0.25）. In the PL spectra of germanium quantum dots formed by the oxidation of Si1-xGex substrate, it is clear that there are several peaks at 724 nm, 769 nm, 810 nm and 861 nm wavelength along the emission band, which are correlated the quantum confinement effect with 3.98 nm, 4.17 nm, 4.35 nm and 4.62 nm diameter of the germanium clusters, respectively. The simulation result with MC method demonstrates that the germanium clusters in above diameters are more stable under above conditions. A quantum confinement model has been set, and some calculations with the UHFR method and the quantum confinement analysis have been proposed to explain the PL spectra.