Open AccessImpact of defects in self-assembled monolayer on humidity sensing by molecular functionalized transistors
Author(s) -
Takahisa Tanaka,
Takeaki Yajima,
Ken Uchida
Publication year - 2020
Publication title -
japanese journal of applied physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 129
eISSN - 1347-4065
pISSN - 0021-4922
DOI - 10.35848/1347-4065/ab80dc
Subject(s) - monolayer , molecule , transistor , self assembled monolayer , dipole , materials science , threshold voltage , chemical physics , penetration (warfare) , optoelectronics , polarization (electrochemistry) , nanotechnology , voltage , chemistry , molecular physics , organic chemistry , physics , quantum mechanics , operations research , engineering
For highly sensitive and selective sensors, numerical study of transistors functionalized with a defected self-assembled monolayer (SAM) was performed. Adsorption of water molecules on the defected SAM was treated by molecular dynamics (MD) calculations. Based on time dependent atomic positions and charges derived from the MD calculations, carrier concentration and threshold voltage of defected-SAM-functionalized transistors were derived from the Poisson equation. The defects of the SAM caused a penetration of water molecules. Due to a strong polarization of water molecules, the water molecules penetrating the defects were stacked in the same direction. The alignment of the water molecules in the defects generated a large electrical dipole, and the threshold voltage of the transistors were shifted.