聚焦电子束诱导碳沉积实现纳米线表面可控修饰

Controllable surface modification of nanowires by focused-electron-beam-induced deposition of carbon

作为一种典型的准一维纳米材料,纳米线具有纳米材料所特有的小尺寸效应或纳米曲率效应,经表面修饰的纳米线一般具有不同于普通纳米线的特殊性质.利用实验室发展成熟的透射电子显微镜原位辐照技术,以透射电子显微镜中残留的有机气体分子为前驱体,成功地在纳米线表面可控沉积了非晶碳纳米颗粒和碳纳米棒,以及局域凸起的非晶碳膜并形成局域肿大的同轴结构.实验结果表明,该方法能够方便地通过控制聚焦电子束的束斑尺寸、辐照方式、辐照时间以及辐照位置等参数,在纳米线表面精确可控地沉积各种非晶碳纳米结构,从而实现纳米线的表面可控修饰.对聚焦电子束辐照下基于纳米线的各种碳纳米结构的可能沉积机理作了进一步地探索,并针对透射电子显微镜中如何减少因电子束辐照诱导非晶碳沉积造成的样品污染提出了几点建议.

Surface-modified nanowires generally own some additional properties,and thus in this paper,the authors particularly studied the surface modification of nanowires via irradiation of focused electron beam in a Tecnai F-30 field emission transmission electron microscope （TEM）.It was observed that controllable deposition of all kinds of amorphous carbon nanostructures,such as carbon particles,carbon rods and carbon films with local bulging,could be got on the surface of nanowires after intentional irradiation.In details,the controllable deposition of carbon nanostructures could be easily and precisely controlled by changing of some irradiation parameters such as beam spot diameter,irradiation manner,irradiation time and irradiation position.The possible deposition mechanisms of carbon nanostructures on the wire surface as induced by irradiation of focused electron beam in TEM were further discussed.In addition,some suggestions were also proposed on reducing of specimen pollution caused by undesired deposition of amorphous carbon materials during the irradiation.