Ultrathin lateral unidirectional bipolar-type insulated-gate transistor as pH sensor

Here, the utilizing of lateral unidirectional bipolar-type insulated-gate transistors (Lubistors) for pH detection was demonstrated for the first time. The high on current and ambipolarity of Lubistors are favorable properties for reliable sensing application. The ultrathin Lubistors were fabricated on 20-nm-thick SOI substrates in planar geometry. The triode-like current-voltage characteristic and excellent gate modulation property for Lubistor were demonstrated. Without any surface modification, this Lubistor based pH sensor was capable of detecting the change of hydrogen ion concentration by the corresponding change in anode current. The anode current revealed nonlinear pH-dependence and complementary change at different working regions. The Lubistor sensor showed stable, reversible and reproducible pH sensing performance. The proposed Lubistor based sensor holds great potential for high reliable biological species detection.