铜箔表面形貌对CVD法生长石墨烯质量的影响

Effect of Copper Foil Surface Morphology on the Quality of Graphene Grown by CVD

为了制备高质量、少层数的石墨烯薄膜,分别用25%HCl、2 mol/L FeCl_3腐蚀液及电化学抛光法处理铜箔,改善其表面平整度,然后利用化学气相沉积法在其表面生长石墨烯。通过调整2 mol/L Fe Cl3腐蚀铜箔的时间和电化学抛光铜箔的参数,根据SEM表征结果确定出腐蚀时间为30 s,抛光电压为10 V,抛光时间为60 s时,铜箔表面最为平整。这些方法处理铜箔后生长的石墨烯经拉曼光谱表征后得出,随着铜箔表面逐渐平整,铜箔表面更易生长出少层数,高质量的石墨烯薄膜。实验中还通过调整化学气相沉积(CVD)炉中通乙烯的时间来制备石墨烯。经SEM和拉曼光谱表征可知,延长生长时间,石墨烯薄膜的层数变厚,生长时间过短则石墨烯生长不连续。生长时间为30 s时,可生长出单层高质量的石墨烯薄膜,且石墨烯薄膜均匀致密;生长时间为60 s时,铜箔表面沉积一层石墨。所以生长单层石墨烯,控制生长时间是必要的。

High-quality and few-layered graphene was grown by chemical vapor deposition（CVD） on copper foils, which were pre- treated by etching with 25% HCl or 2 mol/L FeCl_3 and then electrochemical polishing in order to improve their surface smoothness. The surface morphology of the copper foils and the deposited graphene were characterized by means of Raman spectroscopy, XRD and SEM etc. The results showed that copper foils with desired surface smoothness would be acquired through etching with2 mol/L FeCl_3 for 30 s and then electrochemical polishing for 60 s by applied voltage of 10 V; Films of layered graphene with less defects could be deposited on the pre-treated copper foils. The thickness of graphene films increased with the increasing time, however for a short deposition time the formed graphene films were discontinuous with poor quality. The monolayered high- quality graphene films could be prepared by depositing for 30 s, whilst the deposition time increased to 60 s a graphite film could form on the surface. In other word, it is necessary to control the deposition on time for growing the desired monolayered graphene films.