100 nm scale low-noise sensors based on aligned carbon nanotube networks: overcoming the fundamental limitation of network-based sensors.
Nanoscale sensors based on single-walled carbon nanotube (SWNT) networks have been considered impractical due to several fundamental limitations such as a poor sensitivity and small signal-to-noise ratio. Herein, we present a strategy to overcome these fundamental problems and build highly-sensitive low-noise nanoscale sensors simply by controlling the structure of the SWNT networks. In this strategy, we prepared nanoscale width channels based on aligned SWNT networks using a directed assembly strategy. Significantly, the aligned network-based sensors with narrower channels exhibited even better signal-to-noise ratio than those with wider channels, which is opposite to conventional random network-based sensors. As a proof of concept, we demonstrated 100 nm scale low-noise sensors to detect mercury ions with the detection limit of approximately 1 pM, which is superior to any state-of-the-art portable detection system and is below the allowable limit of mercury ions in drinking water set by most government environmental protection agencies. This is the first demonstration of 100 nm scale low-noise sensors based on SWNT networks. Considering the increased interests in high-density sensor arrays for healthcare and environmental protection, our strategy should have a significant impact on various industrial applications.
Lee
Minbaek
M
Department of Physics and Astronomy, Seoul National University, Shilim-Dong, Kwanak-Gu, Seoul 151-742, Korea.
Lee
Joohyung
J
Department of Physics and Astronomy, Seoul National University, Shilim-Dong, Kwanak-Gu, Seoul 151-742, Korea.
Kim
Tae Hyun
TH
Department of Physics and Astronomy, Seoul National University, Shilim-Dong, Kwanak-Gu, Seoul 151-742, Korea.
Lee
Hyungwoo
H
Department of Physics and Astronomy, Seoul National University, Shilim-Dong, Kwanak-Gu, Seoul 151-742, Korea.
Lee
Byung Yang
BY
Department of Physics and Astronomy, Seoul National University, Shilim-Dong, Kwanak-Gu, Seoul 151-742, Korea.
Park
June
J
Department of Physics, Chung-Ang University, Heukseok-Dong, Dongjak-Gu, Seoul 156-756, Korea.
Jhon
Young Min
YM
Korea Institute of Science and Technology, Hawolgok-Dong, Seongbuk-Gu, Seoul 136-791, Korea.
Seong
Maeng-Je
MJ
Department of Physics, Chung-Ang University, Heukseok-Dong, Dongjak-Gu, Seoul 156-756, Korea.
Hong
Seunghun
S
Department of Physics and Astronomy, Seoul National University, Shilim-Dong, Kwanak-Gu, Seoul 151-742, Korea.|Department of Biophysics and Chemical Biology, Seoul National University, Shilim-Dong, Kwanak-Gu, Seoul 151-742, Korea.