Fabrication and field emission characteristics of a novel planar-gate electron source with patterned carbon nanotubes for backlight units

This paper describes the fabrication of backlight units(BLUs) for a liquid crystal display(LCD) based on a novel planar-gate electron source with patterned carbon nanotubes(CNTs) formed by electrophoretic deposition. The electric field distributions and electron trajectories of this triode structure are simulated according to Ansys software.The device structure is optimized by supporting numerical simulation.The field emission results show that the emission current depends strongly on the cathode-gate gap and the gate voltage.Direct observation of the luminous images on a phosphor screen reveals that the electron beams undergo a noticeable expansion along the lateral direction with increasing gate voltage,which is in good agreement with the simulation results.The luminous efficiency and luminance of the fabricated device reaches 49.1 lm/W and 5500 cd/m2,respectively.All results indicate that the novel planar-gate electron source with patterned CNTs may lead to practical applications for an electron source based on a flat lamp for BLUs in LCD.     

Improvement of the field emission properties of carbon nanotubes by CNT/Fe_3O_4 composite electrophoretic deposition

A simple CNT/Fe_3O_4 composite electrophoretic deposition method to improve the field emission cathode properties of carbon nanotubes(CNTs) is proposed.It is found that CNT/Fe_3O_4 composite electrophoretic deposition leads to better field emission performance than that of single CNT electrophoretic deposition.The result is investigated using SEM,J-E and FE.After the process,the turn-on electric field decreases from 0.882 to 0.500 V/μm at an emission current density of 0.1 mA/cm~2,and the latter increase...     

SnO2 gas sensor fabricated by low frequency alternating field electrophoretic deposition

SnO₂ thick film gas sensor has been prepared by applying low frequency (0.1 Hz) AC electric fields to a stable suspension of SnO₂ nanoparticles in acetylacetone. Parallel gold electrodes were used as the deposition substrate. Effect of CO, O₂ and H₂ gas exposure as well as ethanol vapor on conductivity of the SnO₂ film at 300 °C is investigated. Results show that the sensor is sensitive and its response is repeatable. This work shows that ACEPD can be used as an easy and cheap technique for fabrication of electronic devices such as ceramic-based gas sensors.     

Enhanced electron emission from phosphorus-doped diamond-cladsilicon field emitter arrays

Undoped and phosphorus (P)-doped diamond-clad Si field emitter arrays have been successfully fabricated using microwave plasma chemical vapor deposition (MPCVD) technology. The electron emission from the blunt diamond-clad microtips are much higher than those for the pure Si tips with sharp curvature due to a lower work function. Furthermore, the characteristics of emission current against applied voltage for the P-doped diamond-clad tips show superior emission at lower field to the undoped ones. After the examination of Auger electron spectroscopy (AES) and electrical characteristics of as-grown diamond, such a significant enhancement of the electron emission from the P-doped diamond-clad tips is attributed to a higher electron conductivity and defect densities     

利用场发射扫描电镜的低电压高性能进行材料表征

场发射扫描电子显微镜（FESEM）是一种高分辨扫描电镜,在材料分析中得到广泛应用。尤其是良好的低压高空间分辨性能和低压下良好的SE像相互结合使用,使SEM应用范围得到扩展。     

CNTs/Fe3O4复合电泳提高CNTs阴极场发射性能

A simple CNT/Fe₃O₄ composite electrophoretic deposition method to improve the field emission cathode properties of carbon nanotubes (CNTs) is proposed. It is found that CNT/Fe₃O₄ composite electrophoretic deposition leads to better field emission performance than that of single CNT electrophoretic deposition. The result is investigated using SEM, J-E and FE. After the process, the turn-on electric field decreases from 0.882 to 0.500 V/μm at an emission current density of 0.1 mA/cm², and the latter increases from 0.003 to 1.137 mA/cm² at an electric field of 0.64 V/μm. CNT/Fe₃O₄ composite electrophoretic deposition is an easy and effective cathode preparation for field emission display applications.     

Fabrication of poly-Si thick films by electrophoretic deposition

The electrophoresis of silicon particles in acetone, and the electrophoretic deposition of poly-silicon thick films are reported for the first time. The anodic deposition of Si particles was achieved by applying DC electric fields of ~100 V/cm between two electrodes soaked in a semistable acetone suspension. Uniform layers were reproducibly formed on gold, graphite and silicon wafer anodes (substrates). The technique was successfully applied on substrates of complicated shapes     

基于电流源控制的CNT-FED驱动电路设计

本文为了实现碳纳米管场致发射显示器（CNT-FED）的产品化,采用CNT-FED阴极电流源驱动方法,研究了CNT-FED亮度的均匀性和非线性调节问题。从分立元件驱动电路设计原理出发,采用了高稳定性阴极电流源像素驱动电路,将电流源驱动电路预先制作在硅基底上,再利用室温下生长碳纳米管（CNT）的方法,将CNT发射体和电流源驱动电路集成在同一硅衬底上,最终实现了集成CNT-FED驱动电路的设计。该驱动电路解决了CNT-FED亮度均匀性和非线性调节问题,对场射显示器驱动电路的应用研究和CNT-FED驱动电路的集成化具有参考意义。本文网络版地址：http：//www.eepw.com.cn/article/276357.htm     

A new Pd-InP Schottky hydrogen sensor fabricated by electrophoretic deposition with Pd nanoparticles

In this letter, a new Pd-InP Schottky diode hydrogen sensor fabricated by electrophoretic deposition (EPD) combined with nanosized Pd particles is first proposed and demonstrated. Experimentally, the studied device exhibited excellent current-voltage rectifying characteristics with a large Schottky barrier height (SBH) of 829 meV. At 303 K, a high saturation sensitivity ratio of 38 was found under a very low hydrogen concentration of 15 ppm H/sub 2//air. As raising the hydrogen concentration to 1.0% H/sub 2//air, the SBH lowering of the studied devic"dq"e reached to 307 meV and the sensitivity ratio was high as 1.29/spl times/10/sup 5/ with a very rapid response, which far prevailed over those fabricated by the conventional thermal evaporation and electroless plating techniques. Consequentially, the EPD Pd-InP Schottky diode with extremely effective Pd gate is promising for the fabrication of high-performance hydrogen sensors.     

碳纳米管薄膜的电泳沉积与场发射性能

采用电泳法在Si基片上沉积碳纳米管(CNTs)薄膜。研究了电泳极间距、电泳时间及电泳电压等对沉积的薄膜形貌结构与场发射性能的影响。SEM、高倍光学显微镜和场发射性能测试结果表明,保持阴阳极间距为2cm,在100V的直流电压下电泳2min所获得的CNTs薄膜均匀、连续、致密且具有最好的场发射性能,其开启电场强度仅为1.19V/μm,当外加电场强度为2.83V/μm时,所获得的最大发射电流密度可达14.23×10–3A/cm2。     

脉冲电泳沉积制备电致变色WO3薄膜

采用正交设计法优化了脉冲电泳沉积制备WO3薄膜的工艺参数,并通过分析薄膜的微观结构、透射光谱和循环伏安曲线等研究了最佳工艺条件下制备的WO3薄膜的电致变色性能.结果表明,脉冲电泳沉积制备WO3薄膜的最佳工艺参数为平均电流密度0.2×10-3A/cm2,沉积时间6 min,占空比75%,脉冲周期10 ms.最佳工艺条件下...     

碳纳米管场发射阴极电泳法制备及场发射特性研究

采用电泳沉积法在玻璃基板上成功制备出碳纳米管场发射阴极,采用扫描电子显微镜观察薄膜表面形貌,并对制备的碳纳米管阴极进行场发射测试.实验结果表明电泳2 min沉积的碳纳米管薄膜均匀连续且具有较好的场发射特性,其开启电场为3.1 V/μm,当外加电场强度为11.5 V/μm时场发射电流密度达到11.33 mA/cm2,经过10 V/μm的电场激活处理后样品具有较好的场发射稳定性.     

Microcavity-enhanced electron emission from lead zirconate-titanate cathodes

Enhanced electron emission has been observed from lead zirconatetitanate (PZT) surfaces into which arrays of microcavities have been fabricated by nanopowder blasting. Arrays of microcavities, each having an elliptical cross-sectional geometry with major and minor axis lengths of 800 and 600 μm, respectively, and depths adjustable from 40 to 300 μm, exhibit a pronounced dependence of the emitter electron current on microcavity depth. For electric field strengths at the emitter surface of ∼5-12 V/μm, the RMS current density generated by an array of 250 μm-deep microcavities with a packing density of 214±2 cm^-2 ranges from ∼3 mA cm^-2 to beyond 8 mA cm^-2, or more than a factor of five larger than that produced from a planar PZT surface.     

场发射电子显微镜实验室设计

场发射电子显微镜是新型超高精密的设备,其对机房安装环境有特殊要求。为保证这种电子显微镜获得高分辨率图像,必须严格控制震动和环境磁场的干扰。本文对场发射电子显微镜实验室的防磁、防震和接地等问题进行分析,通过实际施工后的现场检测证实本设计满足了场发射电镜室对环境的技术要求,保证了我校两台场发射电镜顺利安装验收。     

Analysis and simulation of anode heating due to electron field emission

This paper considers the effect of anode heating from energetic electrons produced by field emission. Large electric fields accelerate emitted electrons as they traverse the vacuum gap toward the anode. Electron energy is transferred to the anode by collisions with the lattice. The nonequilibrium transfer of electron kinetic energy to anode thermal energy is examined quantitatively. Results demonstrate that the energy distribution of impinging electrons affects the transmission and dissipation of thermal energy. A Monte Carlo technique is used to resolve the thermalization of electrons and accounts for electron beam strength and spatial distribution. The results indicate that local heat fluxes of the order 10 kW/cm/sup 2/ occur at the anode surface and that heating is a strong function of field strength because of the exponential relationship between applied voltage and current. Under practical conditions, temperature increases of 10/spl deg/C are predicted from a single point emission source.     

Enhancement of electron emission efficiency and stability ofmolybdenum-tip field emitter array by diamond like carbon coating

The effect of diamond like carbon (DLC) films, coated by a layer-by-layer technique using PECVD (plasma enhanced chemical vapor deposition) on the electron emission characteristics of molybdenum (Mo)-tip field emitter array (FEA) is examined. The turn-on voltage was lowered from 80 V for the Mo-tip to 65 V for the DLC-coated Mo-tip FEA while the maximum emission current was increased from 140 μA for the Mo-tip to 320 μA for the DLC-coated Mo-tip FEA composed of 900 emitters. For an anode current of 0.1 (μA/emitter) the gate voltage for the DLC-coated Mo-tip FEA and Mo-tip FEA was about 87 and 107 V, respectively. It was also confirmed that the emission current of a DLC-coated Mo-tip FEA was more stable than that of a Mo-tip FEA     

Stabilized emission from micro-field emitter for electron microscopy

Micro-fabricated field emitter for the application in miniaturized scanning electron microscope (MSEM) was fabricated on silicon substrate. Field emission studies of the micro-fabricated field emitter were carried out in an ultra high vacuum system. A simple voltage controlled feedback circuit was designed and used to regulate the gate voltage in order to improve the emission current stability of the micro-fabricated field emitter. Preliminary results showed that the emission current fluctuation ((I_max − I_min)/I_ave) was reduced from 80% without feedback current stabilizer to less than 1% with the circuit control.