Graphene p-n Vertical Tunneling Diodes
Graphene p-n Vertical Tunneling Diodes
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DOI：
10.1021/nn400899v
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发表时间：
2013-06-01
期刊：
影响因子：
17.1
通讯作者：
Hwang, Euyheon
中科院分区：
文献类型：
--
作者：
Kim, Sung;Shin, Dong Hee;Hwang, Euyheon
石墨烯p-n结的形成和表征是特别感兴趣的，因为p-n结在各种各样的电子/光子系统中用作构建块。石墨烯p-n结以前已经通过使用几种技术形成，但大多数研究都是基于横向型p-n结，没有显示整流行为。在这里，我们报告了一种新型的石墨烯p-n结。我们首先制备并表征了具有两个终端的垂直型石墨烯p-n结。垂直结的最重要的特性之一是不对称整流行为，其在低于+/-10 V的偏置电压下显示出类似于10（3）的开/关比，而在更高的n掺杂浓度下没有选通，这对于实际器件应用可能是有用的。相反，在较低的n掺杂浓度下，p-n结是欧姆的，与克莱因隧道效应一致。所观察到的整流可能是由于在较高的n掺杂浓度下在金属p-石墨烯片和n-石墨烯片之间形成强烈波纹状的绝缘或半导体夹层，其实际上是像金属绝缘体金属或金属半导体金属隧穿二极管的结构。即使在制造后6个月，二极管的特性几乎不变。
Formation and characterization of graphene p-n junctions are of particular interest because the p-n junctions are used in a wide variety of electronic/photonic systems as building blocks. Graphene p-n junctions have been previously formed by using several techniques, but most of the studies are based on lateral-type p-n junctions, showing no rectification behaviors. Here, we report a new type of graphene p-n junction. We first fabricate and characterize vertical-type graphene p-n junctions with two terminals. One of the most Important characteristics of the vertical junctions is the asymmetric rectifying behavior showing an on/off ratio of similar to 10(3) under bias voltages below +/- 10 V without gating at higher n doping concentrations, which may be useful for practical device applications. In contrast, at lower n doping concentrations, the p-n junctions are ohmic, consistent with the Klein-tunneling effect. The observed rectification results possibly from the formation of strongly corrugated Insulating or semiconducting interlayers between the metallic p- and n-graphene sheets at higher n doping concentrations, which is actually a structure like a metal Insulator metal or metal semiconductor metal tunneling diode. The properties of the diodes are almost invariant even 6 months after fabrication.