Structured Epitaxial Graphene and Semiconducting Graphene for Advanced Digital Electronics

石墨烯是由单层碳原子组成的蜂窝状结构，它可以在碳化硅（家用LED照明使用的材料）上自发形成。佐治亚理工学院的研究表明，这种形式的石墨烯可以用来制造晶体管，而晶体管是固态电子产品的基本组成部分。然而，由于石墨烯的基本物理性质，目前石墨烯晶体管仅限于非数字应用。本文提出的研究通过对石墨烯进行创新修饰，克服了这一基本问题，从而使石墨烯晶体管能够用于数字电子产品。如果这项提议的目标成功实现，那么石墨烯可能会通过提供无处不在的硅基电子产品的替代品，对电子工业产生重大影响。基于石墨烯的电子产品可能比基于硅的电子产品更快、更节能，因此它们对社会具有重要意义。这项研究的目的是在碳化硅平台上开发数字石墨烯电子产品。关键目标是证明：(1)场效应晶体管的高通断比(2)场效应晶体管的开关速度与硅基晶体管相当或超过硅基晶体管。(3)功耗低。研究范围如下：50年来，数字电子产品的性能一直呈指数级增长，但由于硅的物理限制，这种增长很快就会结束，而电子工业几乎完全依赖于硅。这种“摩尔定律终结”的情况已经出现了一段时间，而且没有找到可行的替代方案。2003年，佐治亚理工学院的研究人员首次提出，在电子级碳化硅上外延生长的石墨烯是最有希望取代硅的竞争者之一。本研究旨在提供一个原理证明，通过证明高速和低功率场效应晶体管是可行的。这项研究建立在佐治亚理工学院在外延石墨烯领域长达十年的工作基础上。在那个时候，高速晶体管被展示出来。然而，由于石墨烯中缺乏带隙，这些晶体管不能完全关闭，因此它们不节能。最近的研究发现了两种方法来克服这个问题。一种方法是观察到生长在六边形碳化硅端硅面上的石墨烯层实际上是半导体。如果它的移动性足够好，那么它就可以用于高性能的数字电子产品。第二种方法依赖于观察电荷载流子有效地量子力学隧穿石墨烯带的物理间隙。利用静电栅极可调谐隧道电流，形成超薄体场效应隧道晶体管。原则上，这种类型的晶体管有望以非常高的速度和低功耗运行。如果这项研究成功地实现了其最终目标，那么它就有可能彻底改变电子工业，开启人们期待已久的“石墨烯电子时代”。即使这一崇高的技术目标没有实现，这项研究也将代表石墨烯科学的重大进步。

Graphene is a single sheet of carbon atoms arranged in a honeycomb structure and it spontaneously forms on silicon carbide (the same material used for household LED lighting). Research at the Georgia Institute of Technology has shown that this form of graphene can be used to make transistors, which are fundamental components of solid-state electronics. However, currently graphene transistors are limited to non-digital applications because of a fundamental physical property of graphene. The research proposed here overcomes this fundamental problem using innovative modifications of graphene, thereby enabling graphene transistors to be used in digital electronics. If the objectives of this proposal are successfully achieved then graphene may have a significant impact in the electronics industry by providing an alternative to the ubiquitous silicon-based electronics. Graphene-based electronics may be faster and more energy-efficient than silicon-based electronics, and they are therefore of significant importance for society. This research aims to develop digital graphene electronics on a silicon carbide platform. The key goals are to demonstrate:(1) high on-to-off ratios in field effect transistors(2) field effect transistor switching speeds that are comparable to or exceed those of silicon based transistors. (3) low power consumption.The scope of the research is presented below;For 5 decades, digital electronics has seen a relentless exponential growth in performance, but the growth will soon end, due to the physical limitations of silicon, on which the electronics industry almost exclusively relies. This "end of Moores law" scenario has been looming for some time, and no viable alternatives have been found. As first proposed by researchers at the Georgia Institute of Technology in 2003, graphene that is epitaxially grown on electronics grade silicon carbide is one of the most promising contenders to succeed silicon. This research aims to provide a proof of principle, by demonstrating that high-speeds and low power field effect transistors are feasible. The methods and approaches to be usedThis research builds on a decade of work at the Georgia Institute of Technology in the field of epitaxial graphene. In that time, high-speed transistors were demonstrated. Due to a lack of a bandgap in graphene, however, these transistors cannot be fully turned off and therefore they are not energy efficient. Recent research has found two ways to overcome this problem. One relies on the observation that a graphene layer grown on the silicon-terminated face of hexagonal silicon carbide is actually a semiconductor. If its mobility turns out to be sufficiently great, then it can be used for high performance digital electronics. The second method relies on the observation that charge carriers efficiently quantum mechanically tunnel over physical gaps in graphene ribbons. The tunneling current can be tuned using electrostatic gates to form ultra-thin body field effect tunneling transistors. In principle, this type of transistor is expected to operate at very high speed with low power consumption. The intellectual significance of the activityIf this research successfully achieves its ultimate goal, then it has the potential to revolutionize the electronics industry and to kick-off the long awaited "age of graphene electronics." Even if this lofty technological goal is not reached, then none-the-less, this research will represent a significant advance in graphene science.