基于限域纳米尺度液态金属的石墨烯纳米带阵列的调控生长及场效应性能研究

It is of great significance to synthesize graphene nanoribbons with controllable width and edge structure that remarkably determine the material properties. How to achieve quasi one dimensional metal substrate with nanoscale width is a key access to the controllable preparation in the bottom-up way. In this proposal, we design the special “V” shape trenches arrays in the Si substrate, which are geometrically characteristic of nanoscale width gradually increased from bottom to top, flat side wall, regular arrangement, and sharp ditch, to confine the liquid metal for the growth of graphene nanoribbons. This strategy enables the reliable control over the site, space, and length of graphene nanoribbons arrays by the processing of “V” shape trenches. In particular, the width of graphene nanoribbons can be regulated with the width of liquid metal, which is relatively adjusted by the thickness of metal according to the “V” shape geometry; additionally, the edge structure of graphene nanoribbons are expected to be regulated by the interface between liquid metal and side wall of “V” shape trenches. Moreover, we will investigate the performance of field effect transistor (FET) made of the graphene nanoribbons. It is highly desirable that this proposal would open up a novel strategy for accurate control over the nanoscale structure of graphene nanoribbons and elucidation on the structure-performance relationship of graphene nanoribbons-based devices. It is a quotable method to prepare some nanomaterials with special nanoscale structure as well.

制备宽度和边缘结构可控制的石墨烯纳米带具有重大价值。如何直接获得纳米宽度的准一维金属生长基底是采用“自下而上”方法实现石墨烯纳米带控制制备的关键问题所在。本申请拟于硅衬底上构筑具有纳米尺寸宽度、幅宽由底端至顶端逐渐递增、侧壁平整、规则排列、底端尖锐的特定几何结构的“V”型沟槽阵列，以此限域液态金属作为生长基底，通过对“V”型沟槽阵列的设计实现石墨烯纳米带阵列的生长位置、间距、长度的精确控制；通过改变沟槽内部的催化金属的厚度来调节用于石墨烯纳米带生长的液态催化金属表面的宽度，实现石墨烯纳米带宽度的调控；通过液态生长金属与“V”型沟槽的界面优化有望探索出石墨烯纳米带边缘构象的调控途径。进而，研究石墨烯纳米带的纳观结构对场效应晶体管（FET）效能的影响规律。本申请为实现石墨烯纳米带结构的精密控制生长和相关器件的构性规律研究提供了新颖可行的策略，对特定结构纳米材料的控制制备具有重要参考意义。

石墨烯纳米带结构能够利用量子限域效应及边缘效应产生可调带隙，是拓展石墨烯材料在光、电、磁领域应用的重要途径之一。制备宽度和边缘结构可控制的石墨烯纳米带具有重大价值。当前研究中基于“自上而下”策略制备纳米带，在纳米带的结晶质量、边缘结构、宽度等方面缺乏有效控制途径，如何直接获得纳米宽度的准一维金属生长基底是采用“自下而上”方法实现石墨烯纳米带控制制备的关键问题所在。本项目主要研究内容是：（1）纳米尺寸宽度催化生长金属的制备研究。在硅衬底上构筑具有纳米尺寸宽度、幅宽由底端至顶端逐渐递增、侧壁平整、规则排列、底端尖锐的特定几何结构的“V”型沟槽阵列；（2）石墨烯纳米带的CVD生长研究。以此限域液态金属作为生长基底，通过对“V”型沟槽阵列的设计可以实现石墨烯纳米带阵列的生长位置、间距、长度的精确控制；通过改变沟槽内部的催化金属的厚度来调节用于石墨烯纳米带生长的液态催化金属表面的宽度，通过液态生长金属与“V”型沟槽的界面优化探索出石墨烯纳米带边缘构象的调控途径；（3）石墨烯纳米带基场效应晶体管（FET）的效能研究，通过石墨烯纳米带基FET的制造和测试，探究石墨烯纳米带的结构对FET器件效能的影响规律。重要研究成果概括如下：（1）通过反应参数优化，研究了“V”型沟槽与金属基底相互作用对金属基底宽度的影响，制备出纳米尺度石墨烯纳米带阵列；（2）研究了石墨烯纳米带的FET场效应晶体管、低温荧光、电容等性能；（3）研究了氢气对碳原子在金属生长基底的吸附、溶解、扩散、沉积步骤的影响机制；（4）探索了石墨烯纳米结构和层数可控石墨烯的可控合成，为石墨烯带隙调控拓展可靠途径。本项目相关研究成果可为实现石墨烯纳米带结构的精密控制生长和相关器件的构性规律研究提供新颖可行的策略，对特定结构纳米材料的控制制备具有重要参考意义。