Bandgap engineered II–VI quaternary alloys and their humidity sensing performance analyzed by QCM

Abstract

In this research, growth of full composition graded II–VI materials in different morphologies using a simple but versatile chemical vapor deposition method was demonstrated and various characterizations of those materials were carried out using X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy and photoluminescence techniques. All these techniques reveal that our materials were grown in very high crystal quality and providing a unique platform to be used for many applications. In the scope of this paper, we utilized them as humidity sensing materials as they provide a wide variety of morphology change. Humidity sensing properties of those materials were investigated under various humidity levels using quartz crystal microbalance (QCM) system. It was revealed that ZnS-rich ZnCdSSe nanowires have more adsorption sites compared to the other morphologies, namely tapered nanobelt, nanosheet and thin film, and this makes them more sensitive than others. Overall, the fabricated QCM sensors exhibited fast response, high sensitivity and narrow hysteresis and therefore they are very promising for everyday appliances and various manufacturing environments with their easy operation, high sensitivity and stability, ability to work at room temperature and low cost.