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

该项目探索了在基底上以可控方式合成石墨烯的概念，这些基底为晶圆尺寸的扩大提供了很大的潜力。实验的关键部分是通过氧化钇稳定的氧化锆（YSZ）缓冲层在Si（111）上生长的单晶金属薄膜。铂族金属（Ir、Rh、Ru）是用于通过化学气相沉积（CVD）生长石墨烯的优异基底。Ni、Cu和CuxNiy提供了额外的优点，即它们可以被温和的试剂蚀刻，从而使石墨烯保持完整。作为第二个主题，将研究在Ir/YSZ/Si（111）上外延生长的（111）取向金刚石膜的sp3-sp2转换，作为生成外延石墨烯的手段，工作的一个重点是在4英寸Si晶片上合成所需的具有最小镶嵌扩展和低表面粗糙度的单晶质量的无孪晶金属膜。在CVD工艺中，像Ir/YSZ/Si这样的多层结构可以很容易地承受1000°C以上的高温。对于像Cu这样的金属，其对于转移概念是优选的，将探索策略以增加热稳定性，防止在高温下分层，从而允许沉积高质量的石墨烯。石墨烯在金属薄膜上的CVD生长将在奥格斯堡进行研究，并与各种项目合作伙伴合作。作为先前计划的扩展，还打算制备离轴金属和金刚石层。它们的自组织台阶结构有助于诱导石墨烯层的横向图案化。对于从金属生长表面转移到电介质支撑体的三种不同概念将被研究，包括化学以及离子蚀刻技术和机械去除。显微拉曼光谱和LEED将被应用于评估转移膜的结构质量。生长研究的结果将被转移到一个新的CVD设置，允许完整的金属/YSZ/Si（111）晶片的处理。

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.