Yang Ning, Yang Daoguo, Chen Liangbiao, Liu Dongjing, Cai Miao, Fan Xuejun
The Faculty of Mechanical and Electrical Engineering, Guilin University of Electronic Technology, Guilin, 541004, China.
The Department of Mechanical Engineering, Lamar University, Beaumont, 77706, USA.
Nanoscale Res Lett. 2017 Dec 29;12(1):642. doi: 10.1186/s11671-017-2375-3.
In this work, the work function (WF) of graphenes, which are used as electronic devices, has been designed and evaluated by using the first-principle approach. Different states of graphene were considered, such as surface modification, doping, and defects. Firstly, WF strongly depends on the width of pristine graphene. A bigger width leads to a smaller WF. In addition, the effects of hydroxyls, defects, and positions of hydroxyls and defects are of concern. The WF of the graphene which is modified with hydroxyls is bigger than that of the pristine graphene. Moreover, the WF value increases with the number of hydroxyls. Positions of the hydroxyls and defects that deviated from the center have limited influence on the WF, whereas the effect of the position in the center is substantial. Lastly, B, N, Al, Si, and P are chosen as the doping elements. The n-type graphene doped with N and P atoms results in a huge decline in the WF, whereas the p-type graphene doped with B and Al atoms causes a great increase in the WF. However, the doping of Al in graphene is difficult, whereas the doping of B and N is easier. These discoveries will provide heavy support for the production of graphene-based devices.
在这项工作中，通过第一性原理方法对用作电子器件的石墨烯的功函数（WF）进行了设计和评估。考虑了石墨烯的不同状态，如表面改性、掺杂和缺陷。首先，功函数强烈依赖于原始石墨烯的宽度。宽度越大，功函数越小。此外，羟基、缺陷以及羟基和缺陷的位置的影响也受到关注。用羟基改性的石墨烯的功函数大于原始石墨烯的功函数。而且，功函数值随着羟基数量的增加而增大。偏离中心的羟基和缺陷的位置对功函数的影响有限，而中心位置的影响则很大。最后，选择B、N、Al、Si和P作为掺杂元素。掺杂N和P原子的n型石墨烯导致功函数大幅下降，而掺杂B和Al原子的p型石墨烯则使功函数大幅增加。然而，在石墨烯中掺杂Al困难，而掺杂B和N较容易。这些发现将为基于石墨烯的器件的生产提供有力支持。
