Enhancement of Mobility and Modulation of Carrier Concentration in Graphene Field-Effect Transistors via Molecular Doping
Journal
Advanced Materials Interfaces
Journal Volume
8
Journal Issue
19
Date Issued
2021
Author(s)
Abstract
This study demonstrates a molecular doping method by physical vapor molecule adsorption using several functional group compounds. Among these dopants, the amine groups include o-phenylene diamine (OPD), diethylenetriamine (DETA), and tetraethylenepentamine (TEPA); the hydroxyl groups include phenol, catechol, and tetraglycol. A positive correlation between the doping level and the number of functional groups is confirmed in this study. Additionally, it is found that the spatial structure of the dopant molecule is another determinant factor affecting the doping degree and mobility. Thus, the planar dopants with an aromatic ring can be easily rearranged to maximize the interaction with graphene, resulting in a stronger p-doping effect. The work function of graphene is efficiently tuned from 4.3 to 3.83 eV for TEPA-doped graphene and to 4.73 eV for catechol-doped graphene. Molecules with alkyl chains (DETA and tetraglycol) act as compensators that partially neutralize the randomly charged impurity centers in the substrate, increasing the graphene electron mobility from 3068 to 9700 cm2 V–1 s–1 and the hole mobility from 3161 to 3650 cm2 V–1 s–1 compared with that of pristine graphene. © 2021 Wiley-VCH GmbH
Subjects
amine groups; carrier concentration; electron mobility; graphene; hole mobility; hydroxyl groups
Other Subjects
Amines; Carrier concentration; Field effect transistors; Gas adsorption; Graphene transistors; Hall mobility; Hole mobility; Molecules; Phenols; Determinant factors; Diethylenetriamine; Graphene field-effect transistors; Molecular doping; Phenylenediamines; Positive correlations; Spatial structure; Tetraethylenepentamine; Graphene
Type
journal article