Epitaxial multilayers as substrates for the large area growth of graphene: Metal/YSZ/Si(111) and Diamond/Ir/YSZ/Si(111)

该项目探索了在衬底上以受控方式合成石墨烯的概念，这些衬底具有扩大到晶片尺寸的高潜力。实验的关键部件是在Si(111)衬底上通过YSZ缓冲层生长的单晶金属薄膜。铂族金属(Ir、Rh、Ru)是化学气相沉积(CVD)生长石墨烯的良好衬底。镍、铜和铜镍还有一个额外的优点，那就是它们可以用温和的试剂腐蚀，保持石墨烯的完整性。作为第二个主题，我们将研究在Ir/YSZ/Si(111)衬底上外延生长的(111)取向金刚石薄膜的SP3-SP2转化，作为一种产生外延石墨烯的方法。工作的一个重点是在4英寸的硅片上合成所需的单晶质量、最小马赛克扩散和低表面粗糙度的无孪晶金属薄膜。像Ir/YSZ/Si这样的多层结构在CVD工艺中可以很容易地维持1000°C以上的高温。对于铜这样更适合转移概念的金属，将探索提高热稳定性的策略，防止在允许沉积高质量石墨烯的高温下分层。将在奥格斯堡与各种项目伙伴合作，研究石墨烯在金属薄膜上的化学气相沉积生长。作为先前计划的延伸，它还打算制备离轴金属层和金刚石层。它们的自组织阶梯结构有助于诱导石墨烯层的横向图案化。为了从金属生长表面转移到介质载体，我们将研究三个不同的概念，包括化学和离子刻蚀技术以及机械去除。微拉曼光谱和LEED将被用来评估转移膜的结构质量。生长研究的结果将被转移到新的CVD装置中，该装置允许加工完整的金属/YSZ/Si(111)晶片。

The project explores concepts to synthesize graphene in a controlled way on substrates that offer a high potential for an up-scaling to wafer dimensions. The key component for the experiments are single crystal metal films grown via yttria-stabilized zirconia (YSZ) buffer layers on Si(111). Metals of the platinum group (Ir, Rh, Ru) are excellent substrates for growth of graphene by chemical vapor deposition (CVD). Ni, Cu, and CuxNiy offer the additional advantage that they can be etched by mild reagents that leave the graphene intact. As a second topic the sp3-sp2 conversion of (111) oriented diamond films grown epitaxially on Ir/YSZ/Si(111) as a means to generate epitaxial graphene will be studied.One focus of the work is the synthesis of the required twin-free metal films in single crystal quality with minimum mosaic spread and with low surface roughness on 4-inch Si wafers. Multilayer structures like Ir/YSZ/Si can easily sustain high temperatures above 1000°C in the CVD process. For metals like Cu, which are preferable for transfer concepts, strategies will be explored to increase the thermal stability, preventing delamination at high temperatures which allow deposition of high quality graphene. CVD growth of graphene on the metal films will be studied in Augsburg and in cooperation with various project partners. As an extension to the previous plans it is intended to prepare also off-axis metal and diamond layers. Their self-organized step structure could help to induce a lateral patterning of the graphene layers.For the transfer from the metallic growth surface to a dielectric support three different concepts will be investigated which comprise chemical as well as ion etching techniques and mechanical removal. Micro-Raman spectroscopy and LEED will be applied to assess the structural quality of the transferred films. The results of the growth studies will be transferred to a new CVD setup that allows processing of complete metal/YSZ/Si(111) wafers.