Deposition of ZnO film using an open-air cold plasma generator

Under open-air atmosphere, homogeneous non-equilibrium cold plasma was generated stably by high voltage pulsed power (0.8 kV, 20 Hz) excitation of He and O2 gases. By feeding bis(dipivaloylmethanato)zinc (DPM2Zn) into this plasma, transparent flat ZnO films about 200 nm thick were successfully deposited on glass substrates directly under the slit made into the cathode. An XRD measurement revealed that ZnO films had a polycrystalline structure oriented c-axis. By increasing the O2 gas flow rate, the grain size of the polycrystalline ZnO became larger and its crystallinity was improved.