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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Field emission behavior of single n- and p-type black Si pillar structures
摘要： We have investigated the properties of single n- and p-type black silicon (b-Si) pillars with a height of 20 μm under strong electric field and halogen lamp or laser illumination. For both type of b-Si pillar structures, I-V measurements revealed strong activation effects, which consisted in sudden current increases during the first up/down voltage sweeps. The maximum reproducible emission current from a single n-type b-Si pillar structure was about 15 μA. A pronounced saturation region at 240 nA was observed for a single p-type b-Si pillar. The current fluctuation over time showed a standard deviation of 28 % and 2.5 % for n- and p-type single b-Si pillar structures, respectively. Optical switching under halogen lamp illumination resulted in at least 3 times higher saturation currents and showed a linear dependence of the FE current on the laser power.
关键词： black silicon,photoemission,field emission
更新于2025-09-23 15:21:21
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - In-situ Characterization of Structure Evolution of Graphene During Field Emission
摘要： The structure stability of graphene field emitter is important for the performance of field emission devices. In this work, high dose electron beam illumination and high current field emission was applied on the graphene field emitter and its structure evolution and field emission characteristics were investigated using an in-situ TEM measurement system. The relation between structure and performance of graphene emitter was demonstrated. The interaction of electron and graphene was also discussed.
关键词： in-situ TEM,structure,field emission,Graphene
更新于2025-09-23 15:21:21
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Carbon Nanotubes - Recent Progress || Stability and Reliability of an Electrical Device Employing Highly Crystalline Single-Walled Carbon Nanotubes as a Field Emitter
摘要： Carbon nanomaterial is drawing keen interest from researchers as well as materials scientists. Carbon nanotubes (CNTs)—and their nanoscale needle shape—offering chemical stability, thermal conductivity, and mechanical strength exhibit unique properties as a quasi-one-dimensional material. Among the expected applications, field emission electron sources appear the most promising industrially and are approaching practical utilization. However, efforts to construct a field emission (FE) cathode with single-walled carbon nanotubes (SWCNTs) have so far only helped average out a non-homogeneous electron emitter plane with large FE current fluctuations and a short emission life-time because they failed to realize a stable emission current owing to crystal defects of the carbon network in CNTs. The utilization of CNTs to obtain an effective cathode, one with a stable emission and low FE current fluctuation, relies on the ability to disperse CNTs uniformly in liquid media. In particular, highly crystalline SWCNTs hold promise to obtain good stability and reliability. The author successfully manufactured highly crystalline SWCNTs-based FE lighting elements that exhibit stable electron emission, a long emission life-time, and low power consumption for electron emitters. This FE device employing highly crystalline SWCNTs has the potential for conserving energy through low power consumption in our habitats.
关键词： wet coating process,high crystallization,field emission,single-walled carbon nanotube,scratch,thin film,planar light source,cathode luminescence
更新于2025-09-23 15:21:01
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Phase transitions and critical phenomena of tiny grains carbon films synthesized in microwave-based vapor deposition system
摘要： Different peak trends of tiny grains carbon film have been observed under the investigations of the Raman spectroscopy and energy loss spectroscopy. Carbon films known in nanocrystalline and ultrananocrystalline diamond films are synthesized by employing microwave‐based vapor deposition system. Carbon atoms exhibit several state behaviors depending on the incurred positions of their electrons. Different morphology of tiny grains under different chamber pressure is related to different rate of arriving typical energies at/near substrate surface. Those tiny grains of carbon film, which evolved in graphitic state atoms are converted to structure of smooth elements where elongation of atoms of one‐dimensional arrays is as per exerting surface format forces along opposite poles from their centers. Such tiny grains in the film are the cause of v1 peak under the investigation of the Raman spectrum because of the enhanced propagation of input laser signals through channelized inter‐state electron gaps of elongated graphitic state atoms. Those tiny grains of carbon film, which evolved in fullerene state are the cause of v2 peak. The tiny grains related to v1 peak possess a low intensity as compared with the ones which comprised atoms having state behaviors known in their exceptional hardness. Tiny grains representing v1 peak in the Raman spectrum are also the cause of field emission characteristic of a carbon film. Different peak recordings were made for the Raman at defined positions indicating a different state of carbon atoms for a different phase of deposited tiny grains, which is in line to their energy loss spectroscopy.
关键词： field emission,tiny grains carbon films,Raman spectra,phase transition,heat energy,energy loss spectroscopy
更新于2025-09-23 15:21:01
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The technique of visualization and evaluation of the emission site distribution for large area field emitters
摘要： This paper presents a method for online treatment of the distribution pattern of emission sites on the emitter surface, combined with a multichannel registration and processing system of the IVC. Using computerized field emission projector we have studied nanocomposite emitter based on carbon nanotubes "Taunit M" and polystyrene. The distribution pattern of emission sites over the brightness level was obtained as well as the emission area of the sample was determined. Time dependences of the current level, the total brightness and the emission area were registered.
关键词： field emission,emission area,emission sites distribution,carbon nanotubes,nanocomposite emitter
更新于2025-09-23 15:19:57
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Dynamic space-charge-controlled field emission model of current conduction in metala??insulatora??semiconductor capacitors
摘要： A dynamic space-charge-controlled field emission (SCC-FE) model that considers temporal insulator charge variations caused by voltage stress is developed for analyzing the current conduction in insulators in the entire voltage range of measurement, yielding good agreement between experiments and simulations. The usage of prestressed samples in this analysis is essential for accurately estimating the electron affinities of insulators, yielding 1.65 and 1.93 eV as the estimates for Al2O3 films formed on GaN by atomic-layer deposition (ALD) at 200 and 450 °C, respectively, and 1.65 and 1.83 eV for those on SiO2/Si, respectively. Through the bias instability analysis using the method developed here, the voltage-stress tolerance of both Si and GaN metal–insulator–semiconductor (MIS) capacitors with ALD Al2O3 films was found to be enhanced by the high-temperature (450 °C) ALD. The analysis also revealed the fact that the voltage-stress-induced flatband voltage shift of GaN capacitors with the high-temperature Al2O3 films is mainly caused by the Al2O3 charges near the substrate, hence providing a clue to even better bias stability of the GaN capacitors. With possible applications to other wide-bandgap semiconductor (WBGS) capacitors, the dynamic SCC-FE analysis developed here will play an essential role in analyzing not only gate insulator characteristics but also many reliability issues of various WBGS MIS field-effect transistors.
关键词： Al2O3 films,bias instability,atomic-layer deposition,dynamic space-charge-controlled field emission,metal–insulator–semiconductor capacitors
更新于2025-09-23 15:19:57
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Controllable Synthesis of Special Reed-Leaf-Like Carbon Nanostructures Using Copper Containing Catalytic Pyrolysis for High-Performance Field Emission
摘要： Special reed-leaf-like carbon nanostructures have been realized by using chemical vapor deposition (CVD) under the combined action of copper containing catalytic pyrolysis and ammonia (NH3) gas. The nucleation and growth mechanisms of CNLs based on growth parameters are discussed. The Raman spectra of carbon nanotubes (CNTs), CNLs and CNT-CNL composites were measured and found to be strongly influenced by the type of gas. Field emission (FE) properties of CNL-CNT composites were observed with a lower turn-on electric field of 0.73 V/μm, and a higher current density of 18.0 mA/cm2 at an electric field of 2.65 V/μm, which are superior to those of CNTs and flower-like CNLs. This is because there are more field emitters in CNLs inter-planted in CNTs. We consider that the unique FE stability of CNTs and defects in CNLs play a synergetic role on the improved FE properties.
关键词： carbon nanostructure,catalytic pyrolysis,field emission properties,copper catalyst
更新于2025-09-19 17:15:36
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A WSe <sub/>2</sub> vertical field emission transistor
摘要： We report the first observation of a gate-controlled field emission current from a tungsten diselenide (WSe2) monolayer, synthesized by chemical-vapour deposition on a SiO2/Si substrate. Ni contacted WSe2 monolayer back-gated transistors, under high vacuum, exhibit n-type conduction and drain-bias dependent transfer characteristics, which are attributed to oxygen/water desorption and drain induced Schottky barrier lowering, respectively. The gate-tuned n-type conduction enables field emission, i.e. the extraction of electrons by quantum tunnelling, even from the flat part of the WSe2 monolayers. Electron emission occurs under an electric field ～100 V μm?1 and exhibits good time stability. Remarkably, the field emission current can be modulated by the back-gate voltage. The first field-emission vertical transistor based on the WSe2 monolayer is thus demonstrated and can pave the way to further optimize new WSe2 based devices for use in vacuum electronics.
关键词： WSe2,field emission,monolayer,transistor,vacuum electronics
更新于2025-09-19 17:15:36
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Enhanced field electron emission of single-walled carbon nanotubes prepared by imprinting technique
摘要： In this work, single-walled carbon nanotubes (SWCNTs) field electron emitters were fabricated by imprinting SWCNTs on substrates with a silver buffer layer. It was found that the field emission properties of imprinted SWCNTs were significantly improved with turn-on field at 0.62 V/um and threshold field at 1.04 V/um, comparing to screen-printed SWCNTs emitters who had turn-on field at 1 V/um and threshold field at 2 V/um. These improvements of SWCNTs emitters were owing to the directly imprinting method which made SWCNTs have clean surface and more emitters on the substrates. The lower turn-on electric field of field emission was attributed to no impurities encapsulate on the emitters and the large aspect ratio of SWCNTs resulting in high field enhancement factor of 15800. The emission performance of the imprinted cathode was almost unchanged after many times repeated experiments. This simple and low cost technique can fabricate high performance field emission cathodes efficiently and also demonstrates potential applications in many electronic devices.
关键词： Field enhancement factor,Turn-on field,Imprinting,Field emission,Single-walled carbon nanotubes,Temporal stability
更新于2025-09-19 17:13:59
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Trace level toxic ammonia gas sensing of single-walled carbon nanotubes wrapped polyaniline nanofibers
摘要： This paper presents a two-step enhancement and a comprehensive analysis of single-walled carbon nanotubes (SWCNTs) wrapped polyaniline nanofiber (NPANI) ammonia (NH3) gas sensor at room temperature. SWCNT-PANI composites are successfully synthesized using an efficient and cost-effective rapid in situ chemical polymerization method. The structural morphology and modification of the samples are characterized using field-emission scanning electron microscopy and HRTEM. FTIR and Raman spectroscopic studies are also performed to gain a better insight into the chemical environmental interaction in the as-prepared nanocomposite. The analysis confirms the successful formation of the nanocomposite. The observed NH3 gas-sensing response at 10 ppm of SWCNT, f-SWCNT (functionalised SWCNT), and SWCNT-PANI composite sensors are 5%–6%, 18%–20%, and 24%–25%, respectively. The SWCNT-PANI composite sensors have shown higher repeatability, selectivity, long-term stability, and fast response-recovery characteristics as compared to f-SWCNTs and pristine SWCNT sensors. Concentration and temperature dependent gas-sensing studies are also analyzed. The sensor response also shows a linear relationship with NH3 gas concentration and an inverse relationship with increasing temperature.
关键词： Raman spectroscopy,rapid in situ chemical polymerization,ammonia gas sensor,polyaniline nanofiber,field-emission scanning electron microscopy,FTIR,HRTEM,room temperature,single-walled carbon nanotubes
更新于2025-09-19 17:13:59