单双层石墨烯的制备及电导特性调控

Abstract

石墨烯二维材料有着优异的物理、化学特性,在多个科学领域展现出广阔的应用前景.采用化学气相沉积方法在Cu-nI合金表面制备了二维石墨烯薄膜并揭示其生长机制;研究生长时间、温度等对石墨烯覆盖度和晶格质量的影响.通过优化生长条件,成功制备了大面积单层及具有强烈层间耦合作用的Ab堆叠双层石墨烯薄膜.进一步运用表面沉积技术在单层石墨烯上构建零维Au团簇和二维Au薄膜,研究其对石墨烯电导特性的影响;并结合第一性原理计算,揭示Au的形态及覆盖度影响石墨烯电导特性的规律.据此制作了石墨烯场效应晶体管器件,通过精确控制Au的覆盖度,实现石墨烯电导类型和载流子浓度的有效调控,拓展了其在微电子领域的应用.

A hot wall chemical vapor deposition(CVD)system is used to synthesize two-dimensional graphene films on Cu-Ni alloy foils.Growth parameters are modulated to investigate their effects on graphene coverage.By understanding the growth mechanism and optimizing growth parameters,large-area uniform monolayer and strong coupling bilayer graphene are successfully achieved.Based on the monolayer graphene,Au nanoparticles and films are deposited respectively,displaying a size-dependent electronic characteristic:isolated Au nanoparticles produce n-type doping of graphene,while continuous Au films produce p-type doping.First-principle calculations suggest that different doping properties of Au-graphene system are induced by interactions between grapheme and different Au configurations.Accordingly,graphene field effect transistors(FET)are fabricated,with the in situ measurements suggesting the tunable conductivity type and level by well controlling the Au configurations.