Solution-processed low resistivity zinc oxide nanoparticle film with enhanced stability using UV-Vacuum-Heat (UVVH) treatment and polyvinyl alcohol/ polydimethylsiloxane passivation

Electronic devices made from ZnO nanoparticles (ZnO NPs) are limited by high resistivity due to oxygen molecules adsorption on the surface. However, ultraviolet (UV) light can be used to temporarily release oxygen molecules from the surface of the ZnO NPs and increase the majority electron carrier concentration. It has also been experimentally observed that ZnO NPs exhibit low resistivity after exposure to water molecules in ambient environment. The unstable resistivity of the ZnO NPs film when exposed to air and moisture makes it difficult to fabricate and use as an electronic device for sensing applications. This article proposes a UVVH fabrication process that involves photoelectric interactions between ZnO NPs, UV exposure, oxygen, and polymer passivation. By fabricating ZnO NPs films under 365 nm UV irradiation in a vacuum environment, the process aims to achieve two primary goals: enhancing the carrier concentration and reducing post-fabrication oxygen adsorption by passivating the films with a polyvinyl alcohol (PVA) and polydimethylsiloxane (PDMS) composite layer.