Investigation of Two-Dimensional h-BCN Semiconductors

该项目基于最近发现的二维半导体h-BCN可能取代石墨烯作为二维电子器件的候选材料的假设。h-BN的二维晶格结构与石墨烯相同，但石墨烯的位置被硼、氮和碳原子占据。初步测量结果显示，六方BCN具有1.0 ~ 1.5 eV的直接电子带隙。然而，迄今为止，h-BCN的确切原子结构尚不清楚；计算模型预测，在热脱氢后，前体分子双bn环己烷有几种连接形成共价二维层的可能性，迄今为止在实验研究中无法区分。本项目的目标是建立h-BCN的材料科学基础。我们将对h-BCN形成过程中的反应动力学、支撑基质在生长过程中的作用、决定生长的参数空间、局部电导率和全k空间分辨电子带结构有一个基本的了解。实验方法依赖于超高真空下最先进的表面科学显微镜和光谱学方法。该项目的高风险和高回报部分是可行性研究，从基板上剥离h-BCN，用于原型器件制造。探讨h-BCN作为纳米模板在纳米结构生长中的适用性。这项研究的影响预计将是巨大的，因为具有中等电子带隙的石墨烯类材料的可用性，可与硅和砷化镓相媲美，最终可以加速2D电子设备的开发和实施。

This project is based on the hypothesis that the recently discovered 2D semiconductor h-BCN may replace graphene as a candidate material for 2D electronics. The 2D lattice structure of h-BN is identical to that of graphene, but with the graphenic sites occupied by atoms of boron, nitrogen and carbon. Hexagonal BCN exhibits a direct electronic band gap of 1.0 - 1.5 eV in preliminary measurements. However, the exact atomic structure of h-BCN is thus far unknown; computational modelling predicts that there are several possibilities to connect the precursor molecules, bis-BN cyclohexane, to form a covalent 2D layer after thermal dehydrogenation, which thus far have been indistinguishable in experimental studies. The goal of this project is to establish the materials-scientific basis of h-BCN. We will develop a fundamental understanding of the reaction kinetics during the h-BCN formation, the role of the supporting substrate during growth, the parameter space that determines the growth, local conductivities and the full k-space resolved electronic band structure. The experimental approach relies on state-of-the-art surface-scientific microscopy and spectroscopy methods under ultrahigh vacuum. The high risk and high reward component of this project are feasibility studies to exfoliate h-BCN from the substrate for prototype device fabrication. The suitability of h-BCN as nanotemplate for nanostructure growth will be explored. The impact of this study is expected to be huge, as the availability of graphene-like material with a moderate electronic bandgap, comparable to that of silicon and GaAs, could ultimately accelerate the development and implementation of 2D electronic devices.