RUI: A New Approach for the Synthesis of Heteroatom-Doped Graphene and Lateral Heterojunctions

非技术描述：石墨烯是第一个被发现的具有许多奇异性质的二维材料，然而，它的柔性和实际应用仍然受到其一些特定特性的限制。用杂原子（来自与主体材料原子不同的化学元素的原子）取代掺杂石墨烯是调整石墨烯性质并因此扩展其应用的最吸引人的策略之一。本项目研究了使用含杂原子的源材料合成杂原子掺杂的石墨烯和相关的横向结，这是一种新颖的合成方法，并增强了控制掺杂的能力。这项研究还提供了一个原子尺度的结构和电子特性，以及它们之间的相互关系的理解。杂原子掺杂石墨烯可控合成的实现以及对其性质的原子尺度洞察促进了基于石墨烯的电子、储能和催化器件的发展。该项目加强了加州州立大学北岭分校的材料科学研究，这是一个少数民族服务机构，并为研究生和本科生提供合作研究的机会。此外，当地学校的K-12学生还可以通过暑期活动接触到最前沿的研究活动和先进的科学设施。技术说明：精确控制掺杂性质是石墨烯实际应用的关键。掺杂性质强烈地依赖于合成方法、杂原子源和合成参数。探索新的合成方法和新的杂原子来源，以实现对掺杂策略的加强控制是一项紧迫的任务。此外，二维石墨烯p-n异质结是石墨烯基电子器件的关键组件，这进一步推动了这些异质结自下而上生长方法的发展。本研究的目的是开发优化的合成策略，杂原子掺杂的石墨烯和相关的横向异质结从含杂原子的单一前体，这是一种新颖的和有效的合成方法，以及获得原子尺度的洞察掺杂替代品和电子性质之间的相关性。为了实现这些目标，主要的研究工作包括：（1）在不同的合成条件下，采用一系列前驱体/金属体系优化合成，并确定结构和掺杂性质的依赖关系（浓度、空间分布和构型）对前体、底物和合成参数的影响;（2）探索电子性质（能带结构、电荷载流子密度、功函数），通过结合扫描隧道显微镜（STM）、X射线光电子能谱、拉曼光谱和角度分辨光电子能谱测量;（3）改进使用单一前体的石墨烯横向p-n异质结的合成，并通过STM测量表征横向异质结界面处的原子结构和能带排列。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Nontechnical Description: Graphene is the first discovered two-dimensional material with many exotic properties, however, its flexibility and practical applications remain restrained by some of its specific characteristics. Substitutional doping of graphene with heteroatoms (atoms from chemical elements different from the host material atoms) is one of the most fascinating strategies for tuning graphene's properties and hence expanding its applications. This project investigates the synthesis of heteroatom-doped graphene and related lateral junctions using heteroatom-containing source materials, which is a novel synthesis approach and enhances the capabilities for controlling the doping. This research also provides an atomic-scale understanding of the structural and electronic properties, as well as their interrelations. The realization of controlled synthesis of heteroatom-doped graphene and atomic-scale insights into their properties promote the development of graphene-based devices for electronics, energy storage, and catalysis. This project strengthens the materials science research at California State University Northridge, which is a minority serving institution, and provides collaborative research opportunities for graduate and undergraduate students. In addition, K-12 students from local schools receive exposure to cutting-edge research activities and advanced scientific facilities via summer activities.Technical Description: Precisely controlling the doping properties is pivotal toward practical applications of graphene. Doping properties strongly depend on synthesis approaches, heteroatom sources, and synthesis parameters. It is an urgent task to explore new synthesis approaches and new heteroatom sources in order to achieve enhanced control over the doping strategies. In addition, two-dimensional graphene p-n heterojunctions are the key components for graphene-based electronics, which further motivates the development of bottom-up growth approaches for these heterojunctions. The objectives of this research are to develop optimized synthesis strategies for heteroatom-doped graphene and related lateral heterojunctions from heteroatom-containing sole precursors, which is a novel and effective synthesis approach, as well as to gain atomic-scale insights into the correlations between doping alternatives and electronic properties. To accomplish these goals, the main research activities include: (1) optimize the synthesis by employing a series of precursor/metal systems under varied synthesis conditions and identify the dependence of structural and doping properties (concentration, spatial distribution, and configuration) on precursors, substrates, and synthesis parameters; (2) explore electronic properties (band structure, charge carrier density, work function) by combining scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy, Raman spectroscopy, and angle-resolved photoemission spectroscopy measurements; (3) improve the synthesis of graphene lateral p-n heterojunctions using sole precursors, and characterize the atomic structure and band alignments at the interfaces of lateral heterojunctions by using STM measurements.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.