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在氩气的保护下,用具有振镜扫描系统的500 W光纤激光器辐照预置在单晶硅基体上的纳米石墨颗粒。探究了不同激光能量密度下,受激光辐照后的转变产物显微形貌和晶体结构。用透射电镜(TEM)、拉曼光谱、X射线衍射(XRD)分析了所获产物的显微形貌和晶体度。当激光能量密度达到3.33kJ/cm~2时,转变产物的尺寸与原始颗粒尺寸相比有所增大;当激光能量密度达到4.17kJ/cm~2时,可以在样品颗粒表面观察到线状形貌;而当激光能量密度达到8.33kJ/cm~2时,产物由原始的多晶结构转变成了块状的晶体结构。实验结果表明:激光能量密度对单晶硅基体上纳米石墨颗粒显微形貌和晶体结构的转变有很大的影响。
Under the protection of argon, the nano-graphite particles pre-arranged on the monocrystalline silicon substrate are irradiated by a 500 W fiber laser with a galvanometer scanning system. The microstructure and crystal structure of the transformed product after laser irradiation were investigated under different laser energy densities. The morphology and crystallinity of the obtained product were analyzed by transmission electron microscopy (TEM), Raman spectroscopy and X-ray diffraction (XRD). When the laser energy density reaches 3.33kJ / cm ~ 2, the size of the transformed product increases with the original particle size. When the laser energy density reaches 4.17kJ / cm ~ 2, the linear Morphology. When the laser energy density reaches 8.33 kJ / cm ~ 2, the product changes from the original polycrystalline structure to a bulk crystal structure. The experimental results show that laser energy density has a great influence on the morphology and crystal structure of nanocrystalline graphite particles on a single crystal silicon substrate.