Ali Asif, Kim So-Young, Hussain Muhammad, Jaffery Syed Hassan Abbas, Dastgeer Ghulam, Hussain Sajjad, Anh Bach Thi Phuong, Eom Jonghwa, Lee Byoung Hun, Jung Jongwan
HMC (Hybrid Materials Center), Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 05006, Korea.
Center for Semiconductor Technology Convergence, Department of Electrical Engineering, Pohang University of Science and Technology, Cheongam-ro 77, Nam-gu, Pohang 37673, Korea.
Nanomaterials (Basel). 2021 Nov 9;11(11):3003. doi: 10.3390/nano11113003.
The electronic properties of single-layer, CVD-grown graphene were modulated by deep ultraviolet (DUV) light irradiation in different radiation environments. The graphene field-effect transistors (GFETs), exposed to DUV in air and pure O, exhibited p-type doping behavior, whereas those exposed in vacuum and pure N gas showed n-type doping. The degree of doping increased with DUV exposure time. However, n-type doping by DUV in vacuum reached saturation after 60 min of DUV irradiation. The p-type doping by DUV in air was observed to be quite stable over a long period in a laboratory environment and at higher temperatures, with little change in charge carrier mobility. The p-doping in pure O showed ~15% de-doping over 4 months. The n-type doping in pure N exhibited a high doping effect but was highly unstable over time in a laboratory environment, with very marked de-doping towards a pristine condition. A lateral pn-junction of graphene was successfully implemented by controlling the radiation environment of the DUV. First, graphene was doped to n-type by DUV in vacuum. Then the n-type graphene was converted to p-type by exposure again to DUV in air. The n-type region of the pn-junction was protected from DUV by a thick double-coated PMMA layer. The photocurrent response as a function of Vg was investigated to study possible applications in optoelectronics.
在不同辐射环境下，通过深紫外（DUV）光照射对化学气相沉积（CVD）生长的单层石墨烯的电子特性进行了调制。暴露于空气中和纯氧气中的DUV的石墨烯场效应晶体管（GFET）表现出p型掺杂行为，而暴露于真空中和纯氮气中的则表现出n型掺杂。掺杂程度随DUV暴露时间增加。然而，真空中DUV的n型掺杂在DUV照射60分钟后达到饱和。在实验室环境和较高温度下，空气中DUV的p型掺杂在很长一段时间内相当稳定，载流子迁移率变化很小。纯氧气中的p型掺杂在4个月内显示出约15%的去掺杂。纯氮气中的n型掺杂表现出高掺杂效应，但在实验室环境中随时间高度不稳定，向原始状态的去掺杂非常明显。通过控制DUV的辐射环境，成功实现了石墨烯的横向pn结。首先，真空中的DUV将石墨烯掺杂为n型。然后，再次将n型石墨烯暴露于空气中的DUV，将其转换为p型。pn结的n型区域通过厚的双层聚甲基丙烯酸甲酯（PMMA）层保护免受DUV影响。研究了作为Vg函数的光电流响应，以研究其在光电子学中的可能应用。
