BN/Graphene/BN sandwiches for high mobility nanodevices

用于高迁移率纳米器件的 BN/石墨烯/BN 三明治

• 批准号: 242357908
• 负责人: Privatdozent Dr. Charles Gould
• 金额: --
• 依托单位: Lehrstuhl für Experimentelle Physik III
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/242357908?language=en
• 关键词: BN; Graphene; sandwiches; mobility; nanodevices

The mobility of carriers in graphene is commonly used as a figure of merit for the quality of a device. Typical mobilities of up to 10000 cm.V-1s-1 can be achieved in macroscopic structures on SiO2 substrates and up to 200.000 cm.V-1s-1 has been reported in large suspended structures, however this method significantly reduces lithographic options. The search for a more suitable substrate dielectric has recently resulted in a major breakthrough when hexagonal boron nitride (h-BN) was found to significantly increase the electronic quality of graphene devices yielding mobilities of about 140.000 cm.V-1s-1 close to the charge neutrality point. While BN has therefore been seen as a success in terms of material quality, recent experiments on nanostructures of graphene BN substrates revealed no significant improvement in mobilities and disorder density compared to similar structures on SiO2. A general speculation in the field is that the quality is limited by edge disorder, which plays an increasing role as devices are made smaller. While this is a possibility, it has never been confirmed experimentally, and it is also well know that the mobility of even large devices can be seriously deteriorated by anything less than ultra-clean lithography. We therefore postulate that the limiting factor in these BN-graphene nanostructures is indeed lithographically induced, and propose a new processing scheme, based on the basic idea of sandwiching the graphene layer between two protective BN sheets, in order to allow an essentially perfectly clean process, and hopefully produce nanodevices of unprecedented mobility.

石墨烯中载流子的迁移率通常用作器件质量的品质因数。在SiO2衬底上的宏观结构中可以实现高达10000 cm.V-1 s-1的典型迁移率，并且在大型悬浮结构中已经报道了高达200.000 cm.V-1 s-1的迁移率，然而这种方法显著减少了光刻选项。最近，当发现六方氮化硼（h-BN）显著提高石墨烯器件的电子质量，产生接近电荷中性点的约140.000 cm.V-1 s-1的迁移率时，对更合适的衬底电介质的研究取得了重大突破。虽然BN因此被视为在材料质量方面的成功，但最近对石墨烯BN衬底的纳米结构的实验显示，与SiO2上的类似结构相比，迁移率和无序密度没有显着改善。该领域的一个普遍推测是，质量受到边缘无序的限制，随着器件的尺寸越来越小，边缘无序的作用越来越大。虽然这是一种可能性，但它从未被实验证实，而且众所周知，即使是大型设备的移动性也会被任何低于超净光刻的东西严重恶化。因此，我们假设这些BN-石墨烯纳米结构中的限制因素确实是光刻诱导的，并提出了一种新的处理方案，基于将石墨烯层夹在两个保护性BN片之间的基本思想，以允许基本上完全清洁的过程，并有望产生前所未有的移动性的纳米器件。