Yingjun Mao

Surface characterization of titanium oxide films synthesized by ion beam enhanced deposition

Abstract In this article, titanium oxide films were prepared by ion beam enhanced deposition where titanium was evaporated by electron beam and simultaneously bombarded with xenon ion beams at an energy of 40 keV in an O2 environment. X-ray photoelectron spectroscopy and Auger electron spectroscopy were used to research the chemical state and composition of the titanium oxide films. The results show that surface of the film was fully oxidized. After the surface was removed by argon ion sputtering, the results show that Ti2+, Ti3+ and Ti4+ states exist on the sputtered surface. The atomic concentration of all the three titanium states were calculated. The chemical shift of O 1s peak was also observed on the near surface.

Highly oriented rutile-type TiO2 films synthesized by ion beam enhanced deposition

Ion beam enhanced deposition was adopted to synthesize titanium dioxide (TiO2) films. The films were prepared by Ti evaporation and Xe+ ion beam bombardment in an O2 environment. The xenon ion energy varied from 40 to 80 keV. The compositions of the TiO2 films were studied by Rutherford backscattering analysis. All the films were close to stoichiometric. The structure of the films were researched by x-ray diffraction. The results showed that the titanium oxide films exhibit a rutile phase structure with high (200) orientation. The optical properties were also studied using ultraviolet–visible transmission spectrometry.

Blood compatibility of titanium oxide prepared by ion-beam-enhanced deposition

Ion-beam-enhanced deposition (IBED) was used to synthesize biocompatible titanium oxide films. The structural characteristics of the titanium oxide films were investigated by Rutherford backscattering spectroscopy (RBS), Auger electron spectroscopy (AES) and X-ray diffraction (XRD). The blood compatibility of the titanium oxide films was studied by measurement of the blood clotting time and platelet adhesion. The results show that the anticoagulation property of titanium oxide films is improved significantly. The mechanism of anticoagulation of the titanium oxide films was discussed.

Effect of Xe+ bombardment on the formation of highly oriented rutile-type titanium oxide films

Abstract Titanium oxide films were prepared by ion beam enhanced deposition (IBED), where the films were synthesized by depositing titanium atoms by electron beam evaporation and simultaneous bombardment with xenon ions (40 keV). The result shows that the films exhibit a highly oriented (100) rutile-type phase structure. The structure of the films prepared by electron beam evaporation on a titanium oxide thin layer (500A) which has been deposited during ion bombardment was also studied. The degree of orientation of these films was more developed than films grown with ion-assisted bombardment only if the substrate was more than 150°C. The effect of the xenon ion beam bombardment is discussed.

STUDY ON THE GROWTH OF BIAXIALLY ALIGNED YTTRIA-STABILIZED ZIRCONIA FILMS DURING ION BEAM ASSISTED DEPOSITION

(001)-oriented and in-plane aligned yttria-stabilized zirconia (YSZ) thin films were synthesized on Ni–Cr alloy substrates by ion beam assisted deposition. It was found that it is not the 〈111〉 axial channel but the {110} plane channel that will always follow the direction of the bombarding ion beam and will result in the in-plane aligned structure of the YSZ films. At 55° incident angle, the bombarding ion beam is in the {110} plane channel and the 〈111〉 axial channel simultaneously; this produces the optimal biaxial alignment of YSZ films. On YSZ single crystalline substrates or textured YSZ layers, growth of YSZ films will not be controlled by the bombarding ion beam; rather, but the films continue to grow along the lattice orientation of the substrate. The formation of the biaxial alignment is an evolutionally selected process by ion beam selective bombardment. YSZ grains of (001) orientation are resputtered less than other oriented grains under ion beam bombardment, which causes the (001) orientation...

Ion beam assisted deposition of biaxially textured YSZ thin films as buffer layers for YBCO superconducting films

Abstract Biaxially textured Yttria-Stabilized Zirconia films for use as buffer layers of YBCO superconducting films have been deposited on polycrystalline Ni Cr metallic substrates by using ion beam assisted deposition system with dual ion sources. The effects of ion bombardment on biaxial texture and growth mechanism of these films were investigated.

Synthesis of titanium dioxide films by ion beam enhanced deposition

Abstract Titanium dioxide films were prepared by ion beam enhanced deposition (IBED), where the films were synthesized by depositing titanium atoms and simultaneously bombarding with Ne+, Ar+ and Xe+ ion beams respectively at an energy of 40 keV in an O2 environment. Rutherford backscattering spectroscopy (RBS), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) and Raman spectroscopy were used to characterize the deposited films. It was found that the O Ti ratio of films deposited is less than 2 : 1. XPS analysis shows that Ti2+, Ti3+ and Ti4+ chemical states exist on the titanium oxide films. The films deposited at different ion beam bombardment are principally crystalline TiO2 with a rutile structure. The films deposited with Ne+ bombardment exhibit a (1 0 0) preferred orientation. Films deposited with Xe+ bombardment exhibit a high (1 0 0) orientation and increase the (1 0 0) orientation with decreasing ion beam current density. The lattice parameter of the deposited films is larger than that of bulk materials. The grain size of the films is between 20 and 60 nm and decreases with increasing mass of bombarding ions.

Control of the YSZ biaxial alignment on polycrystalline NiCr substrates by ion beam selective resputtering

(001)-oriented and in-plane aligned yttria-stabilized zirconia (YSZ) films were synthesized on polycrystalline NiCr substrates by ion beam assisted deposition (IBAD). The YSZ biaxial alignment were found to be controlled by the assisted argon ion beam bombardment. The incident angle and energy of the assisted bombarding ion beam strongly influence the alignment. The optimal alignment was obtained with the assisted ion beam bombarding at 55° incident angle and 250–500 energy. The Monte Carlo method was used to simulate the alignment formation with argon ions bombarding the zirconia crystals. Results indicated that when the energy of the bombarding ions is less than 50 eV, there is no obvious difference in the sputtering yields and the radiation damage of zirconia between different incident angles. However with the ion energy increasing, the variation increases rapidly. When the ion energy reaches 250 eV, the sputtering yields and the radiation damage of zirconia induced by Ar+ bombarding along [111] direction (54.7° from the [001]) of the zirconia are much lower than those produced by Ar+ bombarding along other directions. It can be concluded that the (001)-oriented grains are resputtered less than other grains when the assisted ions bombarding at 55° incident angle, which causes YSZ grains with (001) orientation to prevail over initial random oriented grains and form the biaxial alignment.

High Jc YBCO film on NiCr alloy with aligned YSZ buffer

Abstract YBCO films on YSZ deposited on the NiCr substrate by the ion beam assisted deposition was fabricated using metallorganic chemical vapour deposition. The YSZ buffer and YBCO film are biaxially aligned. J c (77.3K, 0T) is 4.5×10 4 A/cm 2 . For comparison, the results connected with YSZ buffer by MOCVD are also given.

In-plane texture study of the yttria-stabilized zirconia films fabricated by ion-beam-assisted deposition

Biaxially-textured Yttria-stabilized Zirconia (YSZ) films for use as buffer layers of YBCO superconducting films have been synthesized on Ni-Cr metallic substrates by using ion-beam-assisted deposition (IBAD). And the growth mechanism of biaxially-textured YSZ films controlled by ion beam has been investigated in this paper.