Both n-channel and p-channel thin-film transistors have been realized on ZnO nanoparticle (NP) layers sprayed onto quartz substrates. In this study, nitrogen-doped ZnO-NPs were synthesized using an arc-discharge-mediated gas-evaporation method that was recently developed. Sprayed NP layers were characterized by scanning electron microscopy and Hall effect measurements. It was confirmed that p-type behaving NP layers can be obtained using ZnO-NPs synthesized with lower chamber pressure, whereas n-type conductivity can be obtained with higher chamber pressure. pn-junction diodes were also tested, resulting in clear rectifying characteristics. The possibility of particle-process-based ZnO-NP electronics was confirmed.

ZnO nanoparticle (NP) layers were formed using a simple drop casting process. Applying thermal pressing clearly improved the surface morphology and electrical properties of the as-deposited ZnO NP layers as well as significantly enhanced the transistor characteristics of the NP layers. The effects of thermal pressing on the film surface properties were evaluated by X-ray photoelectron spectroscopy, Kelvin probe microscopy, and photoluminescence spectroscopy. Results suggest that thermal pressing improved the transistor characteristics by decreasing NP surface defects such as oxygen vacancies.