title: Size and surface modification effects on the pH response of Si nanowire field-effect transistors.
abstract: We investigated the effects of Si nanowire (SiNW) dimensions and their surface modifications on the pH-dependent electronic transport characteristics of SiNW Electrolyte-insulator-Semiconductor Field-Effect Transistors (EISFETs). The threshold voltages, Vth's, of all devices were extracted from the Id-Vg characteristics with Vg applied to the reference electrode immersed in different pH solutions, and their pH-dependences were analyzed for various devices. We found that our devices produce the systematic pH-dependence of Vth with respect to the SiNW's length and show significant changes in a linear pH region and a pH sensitivity upon the Si surface modifications. Particularly in the case of the APTES-treated surface, the linear variation was observed in the wide region of pH = 2 to approximately 11 with the sensitivity of 54.7 +/- 0.6 mV/pH. Also we compared our data to a theoretical result based on the Gouy-Chapmam-Stern-Graham model and found a reasonable agreement between them.
authors.affiliation: Department of Physics, Research Institute for Natural Sciences, Hanyang University, Seoul, 133-791, Korea.
authors.forename: In-Bok
authors.initials: IB
authors.lastname: Baek
authors.forename: Xianhong
authors.initials: X
authors.lastname: Li
authors.forename: Seongjae
authors.initials: S
authors.lastname: Lee
authors.forename: Chil Seong
authors.initials: CS
authors.lastname: Ah
authors.forename: Jong-Heon
authors.initials: JH
authors.lastname: Yang
authors.forename: Chan Woo
authors.initials: CW
authors.lastname: Park
authors.forename: Tae-Youb
authors.initials: TY
authors.lastname: Kim
authors.forename: Gun Yong
authors.initials: GY
authors.lastname: Sung