Properties of a nanocrystalline barium titanate on silicon humidity sensor

Abstract

A nanometric barium titanate (BaTiO3) film was fabricated on a silicon (SiO2/Si) substrate by the spin-coating method to make a resistive-type humidity sensor. The humidity sensing properties of the sensor were measured, including sensitivity, hysteresis, and response and recovery times. The sensing properties of the sensor did not change with the level of the applied voltage. The best linearity of the curve of impedance versus relative humidity (RH) appears at the frequency of 100 Hz. The capacitance of the sensor increases as RH increases, especially for low measurement frequency. The peaks of the dielectric loss of the humidity sensor move in the higher frequency direction as RH increases.