Highly Sensitive Hydrazine Detection Using a Vertically Oriented ZnO Nanosheet-based Field-Effect Transistor

Abstract

Hydrazine, a highly toxic compound, is used worldwide in industries as a reducing agent for numerous applications. It has a harmful effect on humans and the environment; therefore, advanced analytical techniques are utilized to monitor hydrazine levels to minimize exposure. In this work, we report the fabrication of vertically oriented ZnO nanosheets based solution-gated field-effect transistor (FET) sensor for the low concentration detection of hydrazine. The ZnO nanosheets between source-drain electrodes were encapsulated with Nafion matrix to enhance stability and selectivity during hydrazine detection. The ZnO nanosheets-based solution-gated FET sensor’s sensing properties are compared with and without different concentrations of hydrazine in buffer solution. Conductance of the solution-gated FET hydrazine sensor showed substantial change upon addition of different concentrations of hydrazine. The fabricated hydrazine sensor exhibits high sensitivity (12150 μ A μ M −1 cm −2 ) in the linear response range of 5–110 nM. The low detection limit (∼1.2 nM; signal-to-noise (S/N) ratio of 3), high sensitivity, stability, and reproducibility are due to the direct growth of nanosheets that provide the controlled morphology and enhanced surface area. Besides, solution-gated FET hydrazine sensor was successfully applied to detect hydrazine in water samples for practical validation of developed hydrazine sensors.