title: The pH sensing characteristics of the extended-gate field-effect transistors of multi-walled carbon-nanotube thin film using low-temperature ultrasonic spray method.
abstract: A novel, simple and low-temperature ultrasonic spray method was developed to fabricate the multi-walled carbon-nanotubes (MWCNTs) based extended-gate field-effect transistors (EGFETs) as the pH sensor. With an acid-treated process, the chemically functionalized two-dimensional MWCNT network could provide plenty of functional groups which exhibit hydrophilic property and serve as hydrogen sensing sites. For the first time, the EGFET using a MWCNT structure could achieve a wide sensing rage from pH = 1 to pH = 13. Furthermore, the pH sensitivity and linearity values of the CNT pH-EGFET devices were enhanced to 51.74 mV/pH and 0.9948 from pH = 1 to pH = 13 while the sprayed deposition reached 50 times. The sensing properties of hydrogen and hydroxyl ions show significantly dependent on the sprayed deposition times, morphologies, crystalline and chemical bonding of acid-treated MWCNT. These results demonstrate that the MWCNT-EGFETs are very promising for the applications in the pH and biomedical sensors.
authors.affiliation: Department of Electronics Engineering and Institute of Electronics, National Chiao Tung University, Hsinchu 30010, Taiwan.
authors.forename: Yun-Shan
authors.initials: YS
authors.lastname: Chien
authors.forename: Po-Yu
authors.initials: PY
authors.lastname: Yang
authors.forename: Wan-Lin
authors.initials: WL
authors.lastname: Tsai
authors.forename: Yu-Ren
authors.initials: YR
authors.lastname: Li
authors.forename: Chia-Hsin
authors.initials: CH
authors.lastname: Chou
authors.forename: Jung-Chuan
authors.initials: JC
authors.lastname: Chou
authors.forename: Huang-Chung
authors.initials: HC
authors.lastname: Cheng