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采用飞秒激光辐照硅和硅锗样品,用扫描电子显微镜(SEM)观察样品,发现样品上产生了某些低维结构。用飞秒激光作用产生等离子体相干驻波对硅和硅锗表面的融蚀模型来解释低维结构的形成机制,发现硅的表面周期约为400 nm的光栅结构在波长719 nm处有较强的光致荧光(PL)峰。该光致荧光的发光强度较小,其机制可从激光的脉宽和重复率两个方面来分析。当激光辐照的能量明显超过硅的融蚀阈值时,光栅形状消失,另一种锥状结构开始形成。控制加工条件,可以获得用于衍射和微分束的纳米光栅。
Samples of silicon and silicon germanium were irradiated with femtosecond laser and observed under a scanning electron microscope (SEM). Some low-dimensional structures were observed on the samples. The formation mechanism of the low-dimensional structure is explained by the ablation model of plasma coherent standing wave with the femtosecond laser on the surface of silicon and silicon germanium. It is found that the grating structure with silicon surface period of about 400 nm is stronger at the wavelength of 719 nm Photoluminescence (PL) peak. The photoluminescence fluorescence intensity is small, the mechanism from the laser pulse width and repetition rate of two aspects to analyze. When the laser irradiation energy significantly exceeds the silicon melt threshold, the grating shape disappears, and another cone-shaped structure begins to form. By controlling the processing conditions, it is possible to obtain nanorods for diffraction and differential beam.