Research Institute for Interdisciplinary Science, Okayama University, Okayama, 700-8530, Japan.
Hanamaki Satellite, Research Center for Industrial Science, Iwate University, Iwate, 025-0312, Japan.
Sci Rep. 2017 Sep 12;7(1):11322. doi: 10.1038/s41598-017-11822-9.
A band gap is opened in bilayer graphene (BLG) by applying an electric field perpendicular to the layer, which offers versatility and controllability in graphene-based electronics. The presence of the band gap has been confirmed using double-gated BLG devices in which positive and negative gate voltages are applied to each side of BLG. An alternative method to induce the electric field is electron and hole doping of each side of BLG using electron-transfer adsorbates. However, the generation of the band gap by carrier doping is still under investigation. Here, we determined whether the electron/hole doping can produce the electric field required to open the band gap by measuring the temperature dependence of conductivity for BLG placed between electron-donor self-assembled monolayers (SAMs) and electron-acceptor molecules. We found that some devices exhibited a band gap and others did not. The potentially irregular and variable structure of SAMs may affect the configuration of the electric field, yielding variable electronic properties. This study demonstrates the essential differences between gating and doping.
在双层石墨烯 (BLG) 中施加垂直于层的电场会在基于石墨烯的电子学中提供多功能性和可控性，从而打开带隙。已经使用双门 BLG 器件证实了带隙的存在，其中正栅极和负栅极电压施加到 BLG 的每一侧。使用电子转移吸附剂对 BLG 的每一侧进行电子和空穴掺杂是诱导电场的另一种方法。然而，载流子掺杂产生带隙的情况仍在研究中。在这里，我们通过测量放置在电子供体自组装单层 (SAM) 和电子受体分子之间的 BLG 的电导率随温度的变化，确定了电子/空穴掺杂是否可以产生打开带隙所需的电场。我们发现，一些器件表现出带隙，而另一些则没有。SAM 的潜在不规则和可变结构可能会影响电场的配置，从而产生可变的电子特性。这项研究表明了门控和掺杂之间的基本区别。
