基于微芯片的透射电子显微镜的低温纳米精度电子束刻蚀与原位电学输运性质测量

Nano-scale lithography and in-situ electrical measurements based on the micro-chips in a transmission electron microscope

利用微芯片制备技术制备了带有电极的原位电学薄膜芯片,并结合自制的原位透射电镜样品台,实现了低温下透射电子显微镜聚焦电子束对InAs纳米线的精细刻蚀以及不同温度下的原位电学性能测量.研究发现,随着刻蚀区域截面积的减小,纳米线的电导率也随之减小.当纳米线的截面积从大于10000 nm2刻蚀至约800 nm2时,纳米线电导的减小速率与截面积的减小具有线性关系.同时利用低温聚焦电子束刻蚀,在InAs纳米线上原位制备了一个10 nm的纳米点,并在77与300 K下对该纳米点进行了电学性能测量.通过测量发现在77 K时出现库仑阻塞效应,发生了电子隧穿现象;而300 K时,热扰动提供的能量使这种现象消失.

In this paper, the in-situ membrane chips with the electrodes are fabricated with the micro-chip technique. Using a home-made in-situ holder, the fine lithography on the InAs nanowires is demonstrated by the focused electron beam at low temperature in a transmission electron microscope. It is found that the conductance of the nanowires decreases linearly with the cross section area decreasing from bigger than 10000 nm^2 down to 800 nm^2 by lithography. With this lithography at low temperature, a 10 nm nano-dot is fabricated on an InAs nanowire, and its electrical properties are measured at 77 and 300 K. The coulomb blockade effect is observed at 77 K due to the electron tunneling, while this phenomenon disappears at 300 K due to the stronger thermal fluctuation.