Electrical Characterization of CdS Nanoparticles for Humidity Sensing Applications

Abstract

Resistive type relative humidity sensors based on CdS nanoparticles were synthesized using the chemical bath deposition (CBD) method. Using the drop-casting method, CdS nanoparticles were deposited between thermally evaporated gold electrodes separated by 17 mu m with the electrodes having channel widths of 1400 mu m and supported on a glass substrate with a thickness of 120 nm. The CdS nanoparticles were exposed to moisture to measure the change in electrical resistance. The resistance of the CdS sensor element changed by 3 orders of magnitude as the relative humidity of the test cell was varied between 17 and 85%. The experimental results demonstrate that CdS nanoparticles are very sensitive to changes in relative humidity and can be used as a sensing element for CdS-based humidity sensor applications.