温度对石墨烯褶皱形成影响的理论研究  

Temperature-dependent graphene wrinkle formation:A theoretical study

作　　者：赵超 丁峰 Chao Zhao;Feng Ding(Shenzhen Institute of Advanced Technology,Chinese Academy of Sciences,Shenzhen 518055,China;Faculty of Materials Science and Energy Engineering,Shenzhen University of Advanced Technology,Shenzhen 518055,China)

机构地区：[1]Shenzhen Institute of Advanced Technology,Chinese Academy of Sciences,Shenzhen 518055,China [2]Faculty of Materials Science and Energy Engineering,Shenzhen University of Advanced Technology,Shenzhen 518055,China

出　　处：《Science China Materials》2024年第7期2210-2216,共7页中国科学（材料科学）（英文版）

基　　金：support of the HighTalent Grant from Shenzhen Institute of Advanced Technology(SIATSE3G0991010);the startup grant from Shenzhen Institute of Advanced Technology and the National Natural Science Foundation of China(22333005).

摘　　要：关于超平整、无褶皱石墨烯的制备的课题目前已引起科学家们的极大关注.理解褶皱形成的机理对于制备超平整、无褶皱石墨烯至关重要.本文通过分子动力学(MD)模拟,研究了单层石墨烯在单层和多层铜衬底上化学气相沉积(CVD)生长过程中的降温过程.结果显示,在单层铜衬底上,石墨烯从1300 K冷却到630 K时,初步观察到了褶皱,而在多层铜衬底上,褶皱形成的起始温度约为1080 K.基于这些模拟,我们提出了褶皱形成过程:首先在铜衬底上形成山丘状原子结构,有利于褶皱成核,然后褶皱在这些位置扩展.此外,我们发现褶皱产生的临界温度与石墨烯层和铜衬底之间的粘附力成反比.我们还探讨了摩擦对褶皱密度的影响,并确定了残余压缩应变与相邻两褶皱之间的距离呈近似线性关系.基于石墨烯与Cu(111)衬底之间的摩擦力与外部压缩载荷之间的平衡关系,我们提出了一个理论模型.模拟结果和理论模型均表明,随着摩擦力的增加,相邻两褶皱之间的距离会减小.The topic of wrinkle-free graphene has currently garnered significant attention from scientists.Understanding the mechanism of wrinkle formation is imperative for fabricating ultra-flat graphene sheets.Here,molecular dynamics(MD)simulations were conducted for graphene on single and multi-layer Cu substrates,respectively,to mimic the cooling process in chemical vapor deposition(CVD)growth.Wrinkles were initially observed in graphene on a single-layer Cu substrate during cooling from 1300 to 630 K,while the initiation temperature for wrinkle formation on a multi-layer Cu surface was approximately 1080 K.Based on these simulations,we proposed a two-step wrinkle formation process:Hill-shaped atomic structures first form on the Cu substrate for wrinkle nucleation,followed by wrinkle propagation at these locations.Moreover,we found a linear decrease in the critical temperature corresponding to the adhesion between the graphene layer and Cu substrate.Notably,we explored the impact of friction on wrinkle density and determined that residual compressive strain was approximately linearly related to distance from the wrinkle.Consequently,we developed an analytical model that considered the frictional forces between graphene and the Cu(111)substrate balanced with external compressive loads.Both simulation results and the analytical model demonstrate that the distance between neighboring wrinkles decreases with increasing friction.

关 键 词：WRINKLES GRAPHENE molecular dynamics simulation chemical vapor deposition 

分 类 号：O613.71[理学—无机化学]