Zinc Oxide Nanorod Field-effect Transistor with Difference Frequency Detection

Nano metal-oxide-semiconductor field-effect transistor (MOSFET) has been widely used in various sensors to achieve high sensitivity due to low-noise property of nano FET. In this paper, we present a novel zinc oxide (ZnO) nanorod FET operated in alternating current mode to implement ultra-sensitive detections. The FET is constructed by cross-connected ZnO nanorods directly grown from opposite ends of drain and source microelectrodes. ZnO nano FET acting as a high-frequency mixer transduces exterior-induced FET conductance change into an alternating current change at a certain difference frequency, which is detected by a lock-in amplifier. The nanorod FET demonstrates ultra-high sensitivity, excellent interference immunity and extremely stable performances.