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 μm with the electrodes having channel widths of 1400 μm 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.

Thin films of CdS nanoparticles were synthesized by the chemical bath deposition (CBD) technique to investigate humidity response characteristics. The morphology and the crystal structure of CdS thin films were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The quartz crystal microbalance (QCM) technique was used to measure the water vapor adsorption and desorption rates of CdS thin films. The dynamic Langmuir model was used to analyze the kinetics of the moisture adsorption and desorption process under relative humidity (RH) between 17 and 85% RH. Our results indicate that CdS thin films have a great affinity to humidity at room temperature.

In order to understand the electronic properties of the organic Schottky diode, ITO/TPD/Al and ITO/SAM/ TPD/Al organic Schottky devices were fabricated to obtain currentvoltage characteristics. From the slopes and y-axis intercepts of the plots, the values of the ideality factor, barrier heights of the ITO/SAM/TPD/Al diode were determined as 2.03 and 0.56 eV, respectively. The surface characterizations of modied and unmodied ITO were performed via atomic force microscopy.