石墨烯掺杂的研究进展_张芸秋

综述

Review

* E-mail: zhoujx@http://m.sodocs.net/doc/8e8deafd59eef8c75ebfb3d5.html

Received February 6, 2014; published February 27, 2014.

Project supported by the NUAA Fundamental Research Funds (No. NS2013096). 项目受南京航空航天大学基本科研业务费(No. NS2013096)资助.

Acta Chim. Sinica 2014, 72, 367—377 © 2014 Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences http://m.sodocs.net/doc/8e8deafd59eef8c75ebfb3d5.html 367

化 学 学 报

ACTA CHIMICA SINICA

石墨烯掺杂的研究进展

张芸秋 梁勇明 周建新*

(纳智能材料器件教育部重点实验室 机械结构力学及控制国家重点实验室 南京航空航天大学航空宇航学院

南京 210016)

摘要 石墨烯的p 型和n 型掺杂调控对于石墨烯基功能器件的构筑至关重要. 近年来, 随着化学气相沉积(CVD)石墨烯技术的发展和广泛应用, CVD 石墨烯掺杂技术及相应性能调控的研究也取得了极大进展. 本文主要介绍了近几年来石墨烯, 特别是CVD 生长石墨烯掺杂研究的发展, 讨论了金属电极接触、气体小分子吸附、氧化性及还原性极性分子吸附及晶格掺杂等多种石墨烯掺杂的方法, 同时介绍了近期出现的对双层石墨烯能带调控以及制造石墨烯p-n 结的研究, 展望了石墨烯掺杂对于其功能器件研究的作用和发展前景. 关键词 石墨烯; 掺杂; 半导体; 带隙

Recent Progress of Graphene Doping

Zhang, Yunqiu Liang, Yongming Zhou, Jianxin*

(Intelligent Nano Materials and Devices , State Key Laboratory of Mechanics and Control for Mechanical Structures , Nanjing

University of Aeronautics and Astronautics , College of Aerospace Engineering NUAA , Nanjing 210016) Abstract Doping is the most feasible and convenient method to modulate the band structure of graphene from semimetal to p-type or n-type material. In recent years, the chemical vapor deposition methods have been well developed to grow graphene layer with high quality and large area. This paper briefly reviews the recent research progress on doping methods of CVD graphene, including the doping effects by metals, small molecules, chemical reactions and replacement of lattice atoms. The methods of bilayer graphene band regulation as well as the fabrication of graphene p-n junction are also introduced, and the future tendency and potential applications of doped graphene are proposed. For graphene, it is relatively easy to produce p-type doping via surface absorption, exposing pristine graphene in those molecules with electron withdrawing groups (H 2O, O 2, N 2, NO 2, PMMA et al.) will lead to evident p-type doping, and graphene of this kind of p-type doping can rapidly recover to its original state when doping molecules are removed. If boron source was introduced into the CVD growth process of graphene, substitutional p-doping that some carbon atoms in graphene hexagonal lattice are replaced by boron atoms can be formed. Compared to the p-type doping, stable n-type doping is not facile for graphene. It has been proved that some elec-tron-donating molecules such as ammonia, potassium, phosphorus, hydrogen and poly(ethyleneimine) (PEI) can produce n-type doping in graphene through surface electron transfer, but these doping effects are unstable. By introducing nitro-gen-containing precursors in growth approach, small part of lattice carbon atoms will be replaced by nitrogen atoms which can result in effectively n-doping effect. Combine the p-type and n-type doping method together, the p-n junction can be produced in mono- or bi-layer graphene, a series of novel functional devices like photothermoelectric devices have been con-structed using these hetero-doped graphene p-n junctions. Keywords graphene; doping; semiconductor; bandgap

1 引言

自2004年石墨烯(Graphene)被以机械剥离的方法制备并被揭示出独特的物性以来, 世界上物理、化学、材料、电子以及工程领域的科学家都对其投注了巨大的研究兴趣. 其研究发起者安德烈•海姆和康斯坦丁•诺沃肖洛夫也因其开创性的工作获得了2010年诺贝尔物理学奖[1]. 石墨烯是一种由单层碳原子组成的平面二维结构, 与石墨类似, 碳原子4个价电子中的3个以sp 2杂化[2]

的形式与最近邻三个碳原子形成平面正六边形连接的蜂巢结构, 另一个垂直于碳原子平面的σz 轨道电子在晶格平面两侧如苯环一样形成高度巡游的大π键. 这种二元化的电子价键结构决定了石墨烯独特而丰富的性能: sp 2键有高的强度和稳定性, 这使其组成的平面六角晶格有极高的强度和热导[3], 实验测得石墨烯的杨氏模量可达近1 TPa 、热导率可达3000 W•m -1•K -1, 与金刚石十分接近; 另一方面, 晶格平面两侧高度巡游的大π键电子又使其具有零带隙半导体和狄拉克载流子特性, 表现出良好的导电性、极高的电子迁移率(2.5×105 cm 2•

DOI: 10.6023/A14020093

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