Papers by Keyword: Field Emission

Abstract: Field emission accelerometer work in vacuum environment, the negative exponential relationship between the current and the distance of the cathode and anode electrode make the accelerometer has high sensitivity and serious non-linearity. A system simulation method by using SIMULINK tools was put forward, and the system simulation model was proposed. The system simulation was carried out under low vacuum and high vacuum environment. On the guidance of the simulation result, the circuit was designed and the performance of accelerometer was tested. The result indicated that the accelerometer have good linearity and sensitivity.

Abstract: The field emission (FE) of the carbon nanotubes (CNTs) modified by hydrocarbon ion treatment with an energy of 80 eV has been demonstrated. Compared with untreated CNTs, the turn-on field and the threshold field of the modified CNTs decreased significantly. Scanning electron microscopy and transmission electron microscopy indicate that, after hydrocarbon ion treatment, the CNTs are coated by amorphous carbon layer at 300°C of substrate temperature and nanoparticles of graphene stacks at 700°C. It is considered that both amorphous carbon and stacked graphene coating layer can decrease the effective surface work function of CNTs and thus increase FE.

Abstract: This paper introduces atomic force microscope (AFM) deposition method to fabricate nanostructures and nanodevices. Field emission theory is introduced in this paper, which provides theoretical explanation for AFM deposition. Dot matrixes are fabricated by AFM deposition on three different substrates, Si, Au and GaAs. Differences of deposition on the three substrates are discussed. AFM deposition has many practical applications. For example, AFM deposition can be used to solder nano components together to improve electrical properties of nanodevices. Besides nanosoldering, AFM deposition can also be used in fabrication of nanodevices. Thus AFM deposition is a valuable research field for future massive applications of nanodevices.

Abstract: The diamond microcrystalline-aggregate array was fabricated by microwave plasma chemical vapor deposition (MPCVD) method. The ceramic with a Ti mental layer is used as substrate. The diamond array was evaluated by Raman scattering spectroscopy, x-ray diffraction spectrum (XRD), scanning electron microscopy (SEM). The field emission properties were tested by using a diode structure in a vacuum. A phosphor-coated indium tin oxide (ITO) anode was used for observing and characterizing the field emission. It was found that the diamond microcrystalline-aggregate array exhibited better electron emission properties. The turn-on field is only 1.1V/μm and a emission current density as high as 1mA/cm2 was obtained under an applied field of 3.3V/μm. The good field emission properties of the diamond microcrystalline-aggregate array are discussed relating to microstructure and electrical conductivity.

Abstract: A new nanostructure, 1D In₂O₃ nanorod, have been grown on single silicon substrates by Au catalyst assisted thermal evaporation of In₂O₃ and active carbon powders. The morphology and structure of the prepared nanorods are determined on the basis of field-emission scanning electron microscopy (FESEM) and x-ray diffraction (XRD). The field-emission properities of In₂O₃ nanorods have been measured and analysed. The growth mechanism of the In₂O₃ nanorods can be explained on the basis of the vapor–liquid–solid (VLS) processes.

Abstract: This paper presents the results of research and development of two types diode structures based on wide bandgap 4H-SiC: drift step recovery diodes (DSRDs) and field emission diodes (FED). Diodes’ structure and manufacturing methods are reviewed. Diode’s characteristics were obtained (static current-voltage characteristics and capacitor-voltage characteristic, switching properties’ characteristics for DSRDs). Field emission 4H-SiC structures illustrated high (≥10² А/сm²) current densities at electric field intensity of approximately 10V/um. 4H-SiC DSRDs in the generator structure with a single oscillating contour allowed to form sub nanosecond impulses at a load 50 Ohm and 1,5-2kV amplitude for a single diode (current density at V=2kV J= 4•10³ А/сm²),what is significantly higher than similar DSRD’s parameters obtained for silicon.

Abstract: Silicon nanowires with fine tip curvature and high aspect ratio are the promising alternative as the electron emitter to promote field electron emission characteristics. The fabrication of silicon nanowires based on the vapor-liquid-solid (VLS) mechanism was performed in the low pressure chemical vapor deposition chamber in the present work. The gold has its lower eutectic point than other materials and deposited on silicon wafer as the catalyst for silicon nanowire synthesis. The structural properties of the nanowires, including number density, size, aspect ratio and tapering geometry, were optimized by various experimental recipes. The results showed that the low turn-on filed of the nanowire was comparable with the published materials. The 1.2 V/μm low turn-on field was detected from the silicon nanowires which have high aspect ratio and tapered tip emitter when the silicon nanowires were synthesized under the reaction conditions at 620 °C grown for 60 minutes with silane and nitrogen flow rates at 100 SCCM.

Abstract: A novel reflective metal anode with different groove structures and a set of parallel long narrow stripe Carbon nanotube (CNT) cathodes to fabricate a 7 inches field emission backlight unit (CNT-FEBLU) has been carried out in this paper. In comparison with a simple diode structure, which has the same stripe cathode unit with screen printing phosphor layer on ITO glass surface as the anode, the reflective metal anode has some advantages such as sustaining high field emission current, no unexpected arcing, and high illumination and uniformity without phosphor degradation. The results show that a reflective metal anode not only conducts the residual charges and heat from the phosphor surface effectively, but also reflects the light to one side of the panel through the cathode end and exhibits high illumination without obvious obstacle by the narrow stripe cathodes. The luminance of the reflective metal groove anode we proposed is 11530 cd/m², with the emission current density of 1.52 mA/cm² under the electric field about 1.07 V/μm.

Abstract: In this paper, a comparative study of temperature effect which introduces a thermionic current under a high applied electric field, on three different modes of field emission current, such as Tunneling current, Fowler-Nordheim current and Field emission current in between these two regions has been done. Moreover, an idea of micromechanical displacement sensor with high sensitivity, operating in Fowler-Nordheim current mode, has been proposed. The displacement sensitivity of proposed sensor in Fowler-Nordheim current domain is about 10-9 m/A. The displacement sensitivity has been shifted from its expected value due to thermal effect (at 700K temperature) at about 1010V/m applied electric field across tip gap.

Abstract: High density、uniform particles diamond films were synthesized by microwave plasma chemical vapor deposition (MWPCVD) method on Si (100). In order to improve field emission properties of thin films, sputtering the metal Ti、Al、Mo、Ni on the diamond surface respectively，and compared the kinds of diamond/metal composite film of field emission performance. The results show that the field emission properties of diamond / metal Ti composite thin film are better. The possible mechanism will be discussed in this study.