Papers by Keyword: Field Emission

Abstract: The test of nano-diamond cathode field emission characteristics was conducted by changing the vacuum, the influence of vacuum change on nano-diamond field emission characteristics was also explored. It was found that under the condition of low vacuum, nano-diamond field emission turn-on field is relatively high, as the vacuum increases, turn-on field decreases gradually, and current density increases. When system vacuum reaches to above 10^-4 Pa level, turn-on field becomes stable, the stable value is 4.5 V/μm; and current density also becomes stable, the stable value is 117 μA/cm²; the luminescence effect of anode which is 200μm distant from the cathode in the vacuum chamber also becomes stable. Results show that 10^-4 Pa is system vacuum limit parameter of stable working of field emission display, the experiment provides a basis to the design and manufacture of nano-diamond field emission display.

Abstract: We report on miniaturized silicon field emitter arrays for the application in compact and energy-saving vacuum-microelectronic devices, e.g. sensors or x-ray tubes. Since standard silicon semiconductor technology has been used for the fabrication, they may be easily integrated with other silicon based circuits and devices on the same chip. The silicon tip geometry and the operating conditions were optimized in order to obtain highly uniform and stable electron field emission from large area cathode arrays. A series of uniform hexagonal tip arrays containing each 547 tips were fabricated and characterized. The electron emission properties of both individual tips as well as of complete emitter arrays were investigated. A saturation level in the voltage-current characteristics was found, which can be explained by the limitation of the supply of electrons due to the p-type silicon wafer material. When operating the arrays in the current saturation regime at an emission current of ~ 1 nA per tip, a highly stable and low noise emission can be observed.

Abstract: Cathode samples of titanium-based nanodiamond field emission were prepared by electrophoresis dispersed solutions in different formulas. Observe the surface and structure of the coating by using metaloscope, microscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD); Test the field emission characteristic after annealing; Analyze the relation between the samples’ light photos and the uniformity of coating; Discuss the mechanism of the improved field emission characteristic after annealing. Under the same conditions the surface uniformity of diamond coating prepared by isobutyl alcohol is best,it is the minimum threshold electric field emission, 5.5 V/μm, the current density can reach to 85μA/cm² at the field of 15V/μm. Field emission characteristic and luminescence could be best after annealing.

Abstract: A flat plate model are employed to investigate the development mechanism of the initial electrons along the insulation surface in this paper, and the field emission properties of pollutant (NaCl) and water (H₂O) adsorbed on the copper electrode are studied. The voltage when partial arc occurs is computed and a flat plate experiment is carried out to validate the computing results. Results indicate that pollutant and water have an important impact on the field emission, where pollutant is more significant than water. Meanwhile, the pollutant and water can increase the probability to form the partial arc.

Abstract: To estimate the field-enhancement factor, the model system of floated sphere in triode configuration of the carbon nanotube was proposed, and the actual electric field and field-enhancement factor at the apex of carbon nanotube were calculated with the image charge method analytically. The field-enhancement factor given as β=3+ρ+W, where ρ is the aspect ratio of the carbon nanotube, and W is the function of geometrical parameters and the anode and gate voltages. The geometrical parameters affects the field-enhancement factor very much, such as the field-enhancement factor decreased rapidly with the increasing of top radius of carbon nanotube, gate-cathode distance and gate-hole size. The field-enhancement factor could be improved via concocting the gate-electrode.

Abstract: Large quantities of ZnS dentalation nanostructures were synthesized successfully at low temperature using a simple chemical vapor deposition method, and the microstructures and field emission properties of the dentalation structures were investigated. The results indicated that the stem of the dentalation structures is single-crystalline but the surfaces of the teeth are amorphous. The photoluminescence properties show a strong green emission at 520.89 nm due to S vacancy. Investigations on the field emission properties of the ZnS dentalation nanostructures imply that the turn-on field is about 5.56V/μm at an anode-cathode distance of 150μm, which should be attributed to the specific sharp tips and high aspect ratios of the present needle-shaped structure. The field emission behavior of the ZnS obeys Fowler-Nordheim relationship. The results could be valuable for using the ZnS nanostructure as cold-cathode field-emission materials.

Abstract: The major purpose of this study is to investigate the effect of aluminum thin film overlaid on the phosphor layer. The aluminum film patterns consisted of intersecting lines or dotted structure. The results show that the aluminum thin film with patterns on the phosphor anode surface enable us to improve the life time of the phosphor and eliminates the charging-up effect on the phosphor layer of the field emission device. The emission current increases significantly, and after 5 minutes continuous emission, the phosphor brightness decrement can be restrained effectively in the demonstration.

Abstract: In the traditional PECVD method for growing carbon nanotubes (CNTs), the electric field is an important parameter. Its role is to orient CNT growth and dissociate the H-C bond from hydrocarbon gases. Therefore, high energy ions, molecules, and radicals as plasma elements can affect the verticality of CNTs. In this paper, a new configuration for an electric field for the growth of field-oriented and long CNTs on a glass substrate at temperatures below 400°C is reported. Simulation and experimental data show that CNTs are grown at a considerably lower voltage than traditional methods. Using this method, growing vertical CNT on such low-cost substrate glass is more possible for CNT-based devices and bio-applications where price is important.

Abstract: In this paper, a single silicon nanoemitter were investigated by means of experiments and simulation models andthe emitters array was fabricated by dry etching using an inductively coupled plasma (ICP) through a three-step process. Besides, in order to understand the field emission phenomenon in nano/micro scale, a novel experimental measurement technique by SEM with nanomotors including the constant voltage and the constant emission modes was developed to measure the accurate field emission properties.The results indicated that etching method is a good way to make the uniform field emitters and the electron field emission from a single nanoemitter is a barrier tunneling, quantum mechanicalprocess.

Abstract: Electron field emission properties of multi-walled carbon nanotubes (MWCNTs)/polyethylene oxide (PEO) thin films composites with (5%, 15%, 25%, 33%, 40% and 50 % loading of MWCNTs) were investigated. JE curved were measured and modeled according to FowlerNordheim theory. Sample with 33% MWCNTs loading showed the best results with the turn on and threshold fields of 7.66 V/μm and 9.72 V/μm respectively. With 15% MWCNTs loading, the highest enhancement factor of 1509 was observed. Excellent current stability, for the duration of about 34 min was observed for all samples. Raman spectroscopy analysis showed a good matrix/filler interaction and thermogravimetric analysis indicated that thermal degradation of the composites occurred in two stages.