Proximity doping effects in epitaxial graphene: substrate, growth and post-growth treatment

外延石墨烯的费米能级位置和载流子密度是各种器件应用的关键特性。实现良好定义和高度均匀的载流子密度对于电量子计量的应用至关重要，特别是对于实现低磁场下的量子霍尔标准。另一方面，载流子密度的可控变化将允许实现p-n结，从而实现新的器件应用和克莱因隧道等基本效应。因此，本项目旨在实现具有最高载流子密度控制的大面积外延石墨烯系统。只有在特定的SiC晶面上以低阶跃高度生长大面积石墨烯，才能获得高度均匀的载流子密度，从而在尽可能低的场中实现完全量化。相反，在交替面的生长将探索实现横向掺杂调制和横向p-n结。facet诱导掺杂将与基于聚合物的后生长分子掺杂相结合，实现各种具有优化性能的器件，用于电量子计量和基础实验。

The position of the Fermi level and thus the carrier density of epitaxial graphene is a key property for various device applications. Achieving a well-defined and highly homogeneous carrier density is crucial for applications in electrical quantum metrology, specifically for the realization of quantum Hall standards in low magnetic field. On the other hand, a controlled variation of the carrier density will allow realization of p-n-junctions enabling novel device applications and the access to fundamental effects such as Klein tunneling. Therefore, this project aims at realizing large area epitaxial graphene systems with the highest possible control of the carrier density. Growing large area graphene with low step heights on specific SiC facets, only, will allow to obtain a highly homogeneous carrier density allowing full quantization in lowest possible fields. In contrast, growth on alternating facets will be explored to realize lateral doping modulation and lateral p-n-junctions. The facet induced doping will be combined with polymer-based post-growth molecular doping to realize various devices with optimized properties for both electrical quantum metrology and fundamental experiments.