화학공학소재연구정보센터
Thin Solid Films, Vol.522, 324-329, 2012
Fabrication of Al doped ZnO films using atmospheric pressure cold plasma
Under atmospheric pressure, homogeneous non-equilibrium cold plasma was generated stably by high voltage pulsed power (1 kV, 20 kHz, 38 W) excitation of a mixture of He and O-2 gases produced by a dielectric barrier discharge setup. By feeding Bis (2 methoxy-6-methyl-3, 5-heptanedione) Zn (Zn-MOPD, C18H3O6Zn) and Tris (2-methoxy-6-methyl-3, 5-heptanedione) Al (Al-MOPD, C27H45O9Al) into this plasma with He carrier gas, transparent flat Al-doped ZnO (ZnO: Al) films about 120-240 nm thick were prepared on glass substrates directly under the slit made into the cathode. Deposition rates of the films were about 20-40 nm/min. The concentration of Al was measured by inductively coupled plasma atomic emission spectroscopy. The composition ratio of Al to Zn was 7.8 mol% when the carrier He gas flow rate of Al-MOPD was 30 cm(3). The average transmittance of all films was more than 85% in the wavelength range from 400 to 800 nm. When the composition ratio of Al/Zn was between 1.1 and 7.8 mol%, the optical band gap of the film increased from 3.28 to 3.40 eV. The resistivity of ZnO: Al film was 2.96 Omega cm at 1.3 mol% of Al/Zn. In addition, the microstructure of the films was studied by X-ray diffraction measurement and field emission scanning electron microscope observation. It was revealed that doped Al is substituted onto the Zn site of the ZnO crystalline structure in ZnO:Al films. (C) 2012 Elsevier B.V. All rights reserved.