Liu Y, Weinert M, Li L
Department of Physics, University of Wisconsin, Milwaukee, WI 53211, USA.
Nanotechnology. 2015 Jan 21;26(3):035702. doi: 10.1088/0957-4484/26/3/035702. Epub 2014 Dec 30.
Graphene vacancies are engineered for novel functionalities, however, the charge state of these defects, the key parameter that is vital to charge transfer during chemical reactions and carrier scattering, is generally unknown. Here, we carried out atomic resolution imaging of graphene vacancy defects created by Ar plasma using noncontact atomic force microscopy, and made the first determination of their charge state by local contact potential difference measurements. Combined with density functional theory calculations, we show that graphene vacancies are typically positively charged, with size-dependent charge states that are not necessarily integer-valued. These findings provide new insights into carrier scattering by vacancy defects in graphene, as well as its functionalization for chemical sensing and catalysis, and underline the tunability of these functions by controlling the size of vacancy defect.
石墨烯空位被设计用于实现新功能，然而，这些缺陷的电荷状态，即化学反应过程中电荷转移和载流子散射的关键参数，通常是未知的。在此，我们使用非接触原子力显微镜对由氩等离子体产生的石墨烯空位缺陷进行了原子分辨率成像，并通过局部接触电势差测量首次确定了它们的电荷状态。结合密度泛函理论计算，我们表明石墨烯空位通常带正电，其电荷状态与尺寸有关，不一定是整数值。这些发现为石墨烯中空位缺陷引起的载流子散射、以及其在化学传感和催化方面的功能化提供了新的见解，并强调了通过控制空位缺陷的尺寸来调节这些功能的可能性。
