A non-destructive n-doping method for graphene with precise control of electronic properties via atomic layer deposition

• Published in: Nanoscale Vol. 8; no. 9; pp. 5000 - 5005
• Main Authors: Han, Kyu Seok, Kalode, Pranav Y, Koo Lee, Yong-Eun, Kim, Hongbum, Lee, Lynn, Sung, Myung Mo
• Format: Journal Article
• Language: English
• Published: England 07.03.2016
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/c5nr08016a

Graphene applications require high precision control of the Fermi level and carrier concentration via a nondestructive doping method. Here, we develop an effective n-doping technique using atomic layer deposition (ALD) of ZnO thin films on graphene through a reactive molecular layer. This ALD doping method is nondestructive, simple, and precise. The ZnO thin films on graphene are uniform, conformal, of good quality with a low density of pinholes, and finely tunable in thickness with 1 Å resolution. We demonstrate graphene transistor control in terms of the Dirac point, carrier density, and doping state as a function of the ZnO thickness. Moreover, ZnO functions as an effective thin-film barrier against air-borne water and oxygen on the graphene, resulting in extraordinary stability in air for graphene devices. ZnO ALD was also applied to other two-dimensional materials including MoS2 and WSe2, which substantially enhanced electron mobility.