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N‐Doped Graphene Field‐Effect Transistors with Enhanced Electron Mobility and Air‐Stability
Author(s) -
Xu Wentao,
Lim TaeSeok,
Seo HongKyu,
Min SungYong,
Cho Himchan,
Park MinHo,
Kim YoungHoon,
Lee TaeWoo
Publication year - 2014
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201303768
Subject(s) - graphene , materials science , doping , field effect transistor , electron mobility , transistor , optoelectronics , electron , nanotechnology , induced high electron mobility transistor , chemical physics , chemistry , electrical engineering , physics , voltage , engineering , quantum mechanics
Although graphene can be easily p‐doped by various adsorbates, developing stable n‐doped graphene that is very useful for practical device applications is a difficult challenge. We investigated the doping effect of solution‐processed (4‐(1,3‐dimethyl‐2,3‐dihydro‐1 H ‐benzoimidazol‐2‐yl)phenyl)dimethylamine (N‐DMBI) on chemical‐vapor‐deposited (CVD) graphene. Strong n‐type doping is confirmed by Raman spectroscopy and the electrical transport characteristics of graphene field‐effect transistors. The strong n‐type doping effect shifts the Dirac point to around ‐140 V. Appropriate annealing at a low temperature of 80 ºC enables an enhanced electron mobility of 1150 cm 2 V −1 s −1 . The work function and its uniformity on a large scale (1.2 mm × 1.2 mm) of the doped surface are evaluated using ultraviolet photoelectron spectroscopy and Kelvin probe mapping. Stable electrical properties are observed in a device aged in air for more than one month.