Department of Electrical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan.
Nano Lett. 2012 Mar 14;12(3):1379-84. doi: 10.1021/nl204024k. Epub 2012 Feb 16.
Direct deposition of high-quality graphene layers on insulating substrates such as SiO(2) paves the way toward the development of graphene-based high-speed electronics. Here, we describe a novel growth technique that enables the direct deposition of graphene layers on SiO(2) with crystalline quality potentially comparable to graphene grown on Cu foils using chemical vapor deposition (CVD). Rather than using Cu foils as substrates, our approach uses them to provide subliming Cu atoms in the CVD process. The prime feature of the proposed technique is remote catalyzation using floating Cu and H atoms for the decomposition of hydrocarbons. This allows for the direct graphitization of carbon radicals on oxide surfaces, forming isolated low-defect graphene layers without the need for postgrowth etching or evaporation of the metal catalyst. The defect density of the resulting graphene layers can be significantly reduced by tuning growth parameters such as the gas ratios, Cu surface areas, and substrate-to-Cu distance. Under optimized conditions, graphene layers with nondiscernible Raman D peaks can be obtained when predeposited graphite flakes are used as seeds for extended growth.
直接在 SiO2 等绝缘衬底上沉积高质量的石墨烯层为开发基于石墨烯的高速电子学铺平了道路。在这里，我们描述了一种新的生长技术，该技术能够在 SiO2 上直接沉积与使用化学气相沉积 (CVD) 在 Cu 箔上生长的石墨烯相比具有潜在可比性的石墨烯层。我们的方法不是将 Cu 箔用作衬底，而是在 CVD 过程中利用它们提供升华的 Cu 原子。所提出技术的主要特点是使用漂浮的 Cu 和 H 原子进行远程催化，用于烃类的分解。这允许在氧化物表面上直接使碳自由基石墨化，形成孤立的低缺陷石墨烯层，而无需进行后生长蚀刻或金属催化剂的蒸发。通过调整生长参数（例如气体比、Cu 表面积和衬底与 Cu 的距离），可以显著降低所得石墨烯层的缺陷密度。在优化条件下，当使用预先沉积的石墨片作为扩展生长的种子时，可以获得不可分辨的 Raman D 峰的石墨烯层。
