The surface of TiO 2 gate of 2DEG-FET in contact with electrolytes for bio sensing use

Abstract

In order to apply two-dimensional electron-gas-field-effect-transistors (2DEG-FETs) for cell-viability sensors, we investigated the chemical/electrical properties of TiO 2 thin films (13–17 nm) prepared with the sol–gel technique on the gate surface of AlGaAs/GaAs 2DEG-FETs. Photochemical/electrochemical reactions on GaAs surface in electrolytes, which induce the degradation of 2DEG-FET performance, are effectively suppressed by introducing a TiO 2 thin film on the gate area of 2DEG-FETs. Compared to conventional ion-selective FETs (ISFETs), the TiO 2/2DEG-FETs in this study exhibit a high sensitivity (410 mV/mM) for H 2O 2 detection. TiO 2 surfaces show better biocompatibility than GaAs surfaces as demonstrated by direct cell culture on these surfaces.