Binglin Zhang

Nano-structure, magnetic and optical properties of Co-doped ZnO films prepared by a wet chemical method

Co-doped ZnO films with nanorod structures are fabricated by a simple wet chemical method combined with an electrodeposition process on the ITO substrates. This method is proved to be a repeatable, low-cost and high-yield route to synthesize Co-doped ZnO magnetical nanocrystals. SEM measurements show the nanorod structure. X-ray diffraction (XRD) spectra demonstrate that the nanorods are ZnO crystals with (1 0 0) and (1 0 1) preferential orientation. X-ray photoelectron spectroscopy results indicate that Co is distributed in the ZnO nanorods. The magnetic properties of the films were investigated by the vibrating sample magnetometer measurement at room temperature. The photoluminescence spectra of the films were measured by an F-4500 fluorospectrophotometer at room temperature, and the results indicate that Co doping causes the red-shift of the band gap.

The field emission properties of graphene aggregates films deposited on Fe-Cr-Ni alloy substrates

The graphene aggregates films were fabricated directly on Fe-Cr-Ni alloy substrates by microwave plasma chemical vapor deposition system (MPCVD). The source gas was a mixture of H2 and CH4 with flow rates of 100 sccm and 12 sccm, respectively. The micro- and nanostructures of the samples were characterized by Raman scattering spectroscopy, field emission scanning electron microscopy (SEM), and transparent electron microscopy (TEM). The field emission properties of the films weremeasured using a diode structure in a vacuum chamber. The turn-on field was about 1.0 V/µm. The current density of 2.1 mA/cm2 at electric field of 2.4 V/µm was obtained.

SYNTHESIS AND OPTICAL PROPERTIES OF THE MULTILAYER STARLIKE ZnO NANOSTRUCTURES

A novel multilayer starlike ZnO nanostructure has been successfully synthesized on a Si (111) substrate at 600°C by chemical vapor deposition using Zn and zinc acetate dihydrate as the source materials. The morphology, structure, and optical properties are investigated by field emission scanning electron microscopy, X-ray diffraction, Raman and photoluminescence (PL) spectrum, respectively. The results show that the multilayer starlike ZnO nanostructures have hexagonal wurtzite structure. The room-temperature PL spectrum shows the dominant green band peak and the weak UV peak. The possible growth mechanism of the multilayer starlike ZnO nanostructures is also discussed.

Field emission digital display tube with nano-graphite film cathode

The field emission digital display tube with a nano-crystalline graphite cold cathode is designed and fabricated. Under the control of the driving circuits, a dynamic digital display with uniform luminance distribution is realized. The luminance of the character segments is 190 cd/m2 at the operating voltage of 900 V. And the stable emission is attained with a fluctuation of about 3% at an average segment current of 75 muA. The results demonstrate that nano-crystalline graphite film is a promising material for cold cathode.

Zinc Oxide Phosphors Synthesized By Cathodic Electrodeposition

Thin film of zinc oxide (ZnO) was electrodeposited from an aqueous solution of Zn(NO3)2 at 70degC on indium tin oxide (ITO)-covered glass substrate. The analysis of X-ray diffraction(XRD) and scanning electron micrograph (SEM) indicated that the obtained ZnO films had a compact hexagonal wurtzite type structure with preferable (002) growth direction. A sharp near UV emission peak located at 380 nm and a strong orange emission peak located at 593 nm are observed in the photoluminescence. Meanwhile, orange red cathode-luminescence was observed and brightness of the cathode-luminescence was enhanced by annealing

Growth and Field Electron Emission Properties of Nano-Structured White Carbon Films

Nano-structured white carbon films were synthesized by microwave plasma chemical vapor deposition. The X-ray diffraction line at 2thetas=21.6deg (d=0.4107 nm) corresponds to the (110) facet of beta modifications of white carbon. The peak position at 283.46 eV in X-ray photoelectron spectrum represents binding energy of C 1s core level of sp1-hybridization of carbon. Field electron emission characteristics of the film were tested

Study on the field emission characteristics of a-C:H films

Hydrogen contained nano-amorphous carbon films (a-C:H) were deposited on Si substrates by using microwave plasma chemical vapor deposition(MPCVD). A low turn-on field of 2.77 V//spl mu/m was obtained. The current density of 0.28 mA/cm/sup 2/ was obtained at electric field of 4.8 V//spl mu/m. When the electric field was increased to 6.85 V//spl mu/m, the current density was dramatically decreased to 0.067 mA/cm/sup 2/. It was found that the surface bonding ratio sp/sup 2//sp/sup 3/ of 1.25 was decreased to 0.53. It was revealed that some of the sp/sup 2/ phase changed to sp/sup 3/ due to arc-discharging, and sp/sup 2/ phase played a important role in field emission for a-C:H films. Field emission measurements from local emission sites of a-C:H films were carried out by using STM, and explained by DG model.

Field electron emission of nano-structure carbon based thin films

Nano-crystalline fullerene-like film, nano-crystalline graphitic film and nano structure amorphous carbon film were prepared by microwave plasma chemical vapor deposition (MPCVD). The nano-structure and surface morphology of the deposited films were identified by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman scattering and scanning electron microscope (SEM). The field electron emission characteristics of the films were studied by a testing method of diode structure in a vacuum chamber. The deposited nano-structure carbon based thin films and phosphor coated indium tin oxide (ITO) film were used to be cathode and anode, respectively. At the initial measurement, a very low turn-on field of 0.6V//spl mu/m was obtained for the three kinds of nano-structure carbon based materials. After cycling of voltage up and down several times, the turn-on field went up to more than 1.0 V//spl mu/m, and the current density decreased. In this paper, we suggest a theoretical model to discuss the field electron emission mechanism for the nano-structure carbon based thin films, and explain the emission characteristics. The surface local states, the bond dangling of carbon atoms and adsorbates on the surface of the films were considered in the theoretical model.

Fabrication of amorphous CN/sub x/:B films by pulsed laser deposition

Amorphous CN/sub x/:B thin films were fabricated on titanium coated ceramic substrate by using a new doping method of pulsed laser deposition, In which graphite target and BN target were alternatively used to be vaporized sources during deposition. As-deposited films were analyzed by x-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, x-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. XRD measurement shows that no any diffraction peaks on the spectrum. The FITR analysis of the sample suggests that the broad absorption band between 500 and 1700cm-1 is attributed to SP2C-C bonding, SP3C-N bonding, and silicon absorption band. Such infrared absorption feature could be further confirmed by Raman spectrum. The electron field emission characteristics of thin films were investigated. The turn-on field was 6.5 V //spl mu/n . The current density was 78/spl mu/A/cm2 at an electric field of 1IV //spl mu/m.

Field electron emission from amorphous CNx:B films

Abstract CN x :B thin films were prepared on titanium coated ceramic substrate by pulsed laser deposition technique (PLD). The microstructure of the film was examined using scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The analyses indicate that the deposited samples are amorphous CN x :B thin films. Field electron emission characteristics of amorphous CN x :B thin films were measured in a vacuum chamber with a base pressure of about 3.2×10 −5 xa0Pa. The turn-on field of the film was 3.5 V/μm. The current density was 60 μA/cm 2 at an electric field of 9 V/μm. The experimental results indicate that this film could be a promising material applicable to cold cathodes.