Preparation And Property Studying Of ZnO Thin Film Fabricated By Magnetron Sputtering

Zinc oxide (ZnO) thin films were successfully prepared onto microscope slides, quartz glasses and silicon wafers by radio frequency magnetron sputtering and DC reactive magnetron sputtering. The As-grown thin films on all three kinds of substrates show excellent c-axis preferred orientation and crystallinity even before annealing treatment. Some samples were annealed at temperature of 100, 200, 300, 400, respectively for those prepared on microscope slides; whereas the films on quartz glasses, silicon wafers were annealed at temperature of 400 , 500 , 600 , 700 , 800 , respectively. Their morphology, X-ray diffraction, thickness and refractive index, photoluminescence spectrum (emission spectrum and excitation spectrum), Raman spectrum, ultraviolet-visible absorption spectrum were investigated by Atomic Force Microscope(AFM), X-ray Diffractometer, Spectroscopic Ellipsometer, Fluorescence Spectrophotometer, Raman Scattering Spectroscope, Uv-Vis-Nir Scanning Spectrophotometer(UV-visible), respectively. During the inspection by AFM, we found that the surfaces of samples fabricated by both methods are even, smooth. The films are composed of some excellent columnar crystallites with preferred growth direction perpendicular to the surface of the substrate; there're also some isolated isles on the surface of samples prepared by DC reactive magnetron sputtering which are opaque during the inspection by AFM, showing the existence of aggregates of metallic zinc atoms. This is the result of insufficient oxidization of the metallic zinc; the XRD results show that the As-grown thin films exhibit excellent C axis orientation even without annealing treatment. After annealing at various temperatures, this phenomenon is much more prominent; by resorting to Sherrer Equation, we figure out that the crystallites of the samples become bigger with elongation of sputtering duration or improvement of annealing treatment, the longer the sputtering duration is, or, the higher the annealing temperature is, the bigger the crystallites are; for those prepared by DC magnetron sputtering is bigger than those prepared by r.f. magnetron sputtering. With the help of spectroscopic ellipsometer, we found that the thickness is linear to sputtering time given the working pressure being fixed; the relationship between the thickness of the films and working pressure are irregular, but generally it's reciprocal; the optimal working pressure is O.VPa to 2.0Pa, the growth rate is about 40nm/h, the refractive index is about 2.01; Raman spectrum shows that the films developed by magnetron sputtering possessing excellent crystallinity. 437cnT' is the RAMAN eigenvalue spectrum of ZnO bulk, the appearance of this peak in the films is associated with the preferred (002) peak; the optimal excitation wavelength locates about 265.00nm. There're three emission peaks A, B and C existing in the emission spectra, locate around 37X.Xnm, 42X.Xnm, 469.7nm respectively; the first two spectra A and B exhibit a kind of "blue-shift" with the decrease of the size of crystallites, while the third one C keeps comparatively intact in its location. Peak A is associated with the eigenvalue spectrum of ZnO thin films, its blue-shift can be attributed to the widening of the band gap due to quantum size effect; peak B is associated with the electrons' transition from the defect level of the crystallite's boundary to the valence band; peak C is associated with the transition from the bottom of the conduct band to the acceptor level and from donor level to the top of the valence band; for different samples fabricated on quartz glasses with different sputtering time, their absorption edge in UV-visible absorption spectrum is around 376.00nm, the band gap width is 3.3eV.ZnO thin films fabricated by r.f. magnetron sputtering and DC reactive sputtering exhibitexcellent photocatalytic specialties in phenol solutions. During the degradation of phenol solutions, we find that there're some intermediate resultants produced after the decomposition begins. These are the first batch of produ...