title: Quantitative probing of surface charges at dielectric-electrolyte interfaces.
abstract: The intrinsic charging status at the dielectric-electrolyte interface (DEI) plays a critical role for electrofluidic gating in microfluidics and nanofluidics, which offers opportunities for integration of wet ionics with dry electronics. A convenient approach to quantitatively probe the surface charges at the DEI for material pre-selection purpose has been lacking so far. We report here a low-cost, off-chip extended gate field effect transistor configuration for direct electrostatic probing the charging status at the DEI. Capacitive coupling between the surface charges and the floating extended gate is utilized for signal transducing. The relationship between the surface charge density and the experimentally accessible quantities is given by device modeling. The multiplexing ability makes measuring a local instead of a globally averaged surface charge possible.
authors: Department of Electrical Engineering, Yale University, New Haven, Connecticut 06520, USA.
authors: Weihua
authors: W
authors: Guan
authors: Nitin K
authors: NK
authors: Rajan
authors: Xuexin
authors: X
authors: Duan
authors: Mark A
authors: MA
authors: Reed
mesh_terms: D017097:Electric Impedance; D055615:Electrical Equipment and Supplies; D004573:Electrolytes; D006863:Hydrogen-Ion Concentration; D055616:Microtechnology / Q000295:instrumentation*; D017655:Silicon Compounds / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D013499:Surface Properties
chemical_list: D004573:Electrolytes; D017655:Silicon Compounds; D012822:Silicon Dioxide; C032734:silicon nitride