Authors: S. Hartner, A.S.G. Khalil, M. Ali, M. Winterer, H. Wiggers
Affilation: University Duisburg-Essen, Germany
Pages: 535 - 537
Keywords: ink jet printing, Dimatix 2800, ZnO, thin film, stable dispersion, impedance, sensor, condcutivity, electron beam lithography, IDC
Stable aqueous dispersions of ZnO NPs are successfully prepared with a new polymeric stabilizer. The dispersions are stable for at least 2 months without any observable sedimentation. The zeta potential and the size of the nanoparticles have been monitored for several weeks and showed constant values. These stable dispersions have been used to form ZnO NP films using a Dimatix 2800 ink-jet printer. Low porosity layers of ZnO NP with thicknesses between 100-250 nm have been fabricated on different substrates. For electrical characterization, ink-jet printed thin films on interdigital capacitors are investigated. The interdigital structures were prepared by e-beam lithography. The ZnO thin films are measured from room temperature up to 473K in ambient conditions and hydrogen atmosphere. The measurements under ambient conditions show an increase in conductivity with increasing temperature. For simple testing of the sensing properties, the same sample was exposed to hydrogen atmosphere after finishing the measurements in air. Compared to the measurements in air, the resistance in hydrogen decreases by a factor of five even at room temperature. In contrast to established technologies used for the formation of sensor devices, no annealing or post-processing is required.