IVESC 2004. The 5th International Vacuum Electron Sources Conference Proceedings (IEEE Cat. No.04EX839)最新文献

{"title":"The optimization of (Cs,O) activation of NEA photocathode","authors":"Du Xiao-qing, Chang Ben-kang, Du Yu-jie, Li Min","doi":"10.1109/IVESC.2004.1414231","DOIUrl":"https://doi.org/10.1109/IVESC.2004.1414231","url":null,"abstract":"As one of the main direction of developing negative electron affinity (NEA) photocathode with higher response performance, the research work on (Cs,O) activation technique of NEA photocathode has been carried. At present the main adoptive activation technique is the \"high-low temperature\" two-step activation. Although NEA photocathode with high sensitivity has been already prepared by use of this activation method, the research work of activation technique is still semi-experienced and semi-quantitative and therefore the lack of the theoretic guidance of further optimization of activation technique is existent. It is owing to the lack of effective on-line measurement means, and there is not enough useful information obtained during activation. As a result clear and, reasonable explanations for mechanism of activation technique and the details of NEA formation during activation have been inadequate. In this paper, the on-line measurement technology of spectral response and photocurrent are firstly used to research on the \"high-low temperature\" two-step (Cs,O) activation process of NEA photocathode. A series of GaAs slices were activated and different activation manners were adopted by changing Cs and O exposure coverage in activation cycles. On-line spectral response curves and the dependent curves of photocurrent with (Cs,O) activation cycles were measured during each different activation process, and the variations of photoemission performance parameters of photocathodes, which include threshold wavelength, peak response, peak wavelength, sensitivity and surface escape probability with (Cs,O) deposition cycles were calculated according to the measured curves. By analysis of the relations between different \"high-low temperature\" activation technique and sensitivity and stability of NEA photocathode, the optimized (Cs,O) activation technique was obtained and the relations between \"high temperature\" activation and \"low temperature\" activation was also discovered in this paper. In view of the interaction of GaAs surface and (Cs,O) overlaying atoms and the surface analysis results of GaAs(Cs,O) surface, the formation of NEA surface during activation and mechanisms \"high-low temperature\" activation were further explored. It was concluded that the surface of NEA photocathode is composed of GaAs-O interface barrier and Cs-O layer, and the purpose of optimization of activation technique is to make an optimized GaAs-O interface barrier with enough small layer thickness and uniform distribution of GaAs-O bonding, and to make an optimized Cs-O layer with sufficient numbers of Cs-O dipoles at a thinner Cs-O layer. The reasons why higher sensitivity can be achieved by \"low-temperature\" activation compared to \"high-temperature\" activation are that optimized GaAs-O interface barrier is obtained by low-temperature heat cleaning and the optimized Cs-O layer is also sequentially obtained at the existence of GaAs-O barrier.","PeriodicalId":340787,"journal":{"name":"IVESC 2004. The 5th International Vacuum Electron Sources Conference Proceedings (IEEE Cat. No.04EX839)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129751512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Key skill study of impregnated cathode unit applied in multiple beam klystron","authors":"Y. Shiji, Ding Yaogen, Jiang Zhen-bai, D. Feng, Wang Caiying","doi":"10.1109/IVESC.2004.1414267","DOIUrl":"https://doi.org/10.1109/IVESC.2004.1414267","url":null,"abstract":"Multiple beam klystron (MBK) was rapidly developed in recent 20 years because of its unique excellence. Impregnated cathode unit (ICU) with high electronic emission density is one of key technology for manufacture of multi-beam klystron. In this paper, some experiment was made in process of preparing MBK cathode unit. Also several skills were applied to make impregnated cathode unit. The ICUs used in MBK had achieved good result, not only the emission density was satisfied with the demand of device, the problem of electron gun breakdown was overcome also, and the reliability of MBK was improved finally.","PeriodicalId":340787,"journal":{"name":"IVESC 2004. The 5th International Vacuum Electron Sources Conference Proceedings (IEEE Cat. No.04EX839)","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124455028","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Theoretical approach to the stoichiometric feature of field emission from Al/sub x/Ga/sub 1-x/N","authors":"T. S. Choi, M. Chung","doi":"10.1109/IVESC.2004.1414225","DOIUrl":"https://doi.org/10.1109/IVESC.2004.1414225","url":null,"abstract":"The field emission current density j from the ternary alloy Al/sub x/Ga/sub 1-x/N is calculated as a function of a stoichiometric composition x for 0/spl les/x/spl les/1. In addition to the doping, the internal field emission is considered to contribute to the carrier concentration n of the conduction band of Al/sub x/Ga/sub 1-x/N. A full calculation is made to obtain the exact j from Al/sub x/Ga/sub 1-x/N as a function of x and the field F. Then we found the stoichiometric dependence of field emission from Al/sub x/Ga/sub 1-x/N by analyzing the effects of both the electron affinity and the carrier concentration.","PeriodicalId":340787,"journal":{"name":"IVESC 2004. The 5th International Vacuum Electron Sources Conference Proceedings (IEEE Cat. No.04EX839)","volume":"93 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114473614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synthesis and electron emission properties of aluminum nitride nano-cones","authors":"C. Liu, Q. Wu, X.Z. Wang, Z. Hu, Y. Chen, S. Deng, N. Xu","doi":"10.1109/IVESC.2004.1414158","DOIUrl":"https://doi.org/10.1109/IVESC.2004.1414158","url":null,"abstract":"Summary form only given. Aluminum nitride nanowires have displayed superior field emission due to the combination of negative electron affinity and one-dimensional geometry. Here, we report on the preparation and field emission properties of quasi-aligned aluminum nitride nano-cones on the silicon wafer. These nano-cones are formed via the reaction between AlCl/sub 3/ vapor and NH/sub 3//N/sub 2/ gas at the temperature ranging from 700/spl deg/C to 800/spl deg/C under nickel catalyst. The subsequent analyses including X-ray diffraction, scanning electron microscopy and transmission electron microscopy indicate that these cones have wurtzite phase and grow preferentially along c-axis with the linear decreasing diameter. The diameters of the tips of these cones are measured to be between 20 and 50nm. Field emission measurements were carried out in the vacuum chamber at the pressure of 1 /spl times/ 10/sup -7/ Torr at the ambient temperature. From the characteristic current-voltage curves, it is revealed that the turn-on voltage is about 12V//spl mu/m comparable with that of GaN nanowires. Based on the Fowler-Nordheim plot with two-stage slope, the field enhancement factors are calculated to be about 400 and 1200 respectively. These results indicate that these AlN nano-cone arrays may have promising application in field of electron emission emitters.","PeriodicalId":340787,"journal":{"name":"IVESC 2004. The 5th International Vacuum Electron Sources Conference Proceedings (IEEE Cat. No.04EX839)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126847130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heatproof improvement of Ag-CNT print-film by boron addition","authors":"S. Sasaki, M. Okaia, S. Hirasawa, Y. Kaneko","doi":"10.1109/IVESC.2004.1414228","DOIUrl":"https://doi.org/10.1109/IVESC.2004.1414228","url":null,"abstract":"Carbon nanotubes (CNTs) have been widely studied as electron sources for field emission displays (FEDs). This report concerns heatproofing CNT electron sources formed by screen-printing. Silver-particles are often added to the CNT print paste to secure electro-conductivity in the film and/or to harden the film. However, when the Ag-CNT paste is baked in air, silver promotes the combustion of CNTs. Therefore, to lower the temperature of the heating process or to carry out the heating process in inactive atmospheres (Kim et al., 2001) is necessary in FED-panel-manufacturing, so as not to burn CNTs. The heating process in air is preferred because the heating process in inactive atmospheres raises the FED manufacturing cost. It is known that adding boron to carbon materials improves their heat resistance (McKee, 1991). We made an attempt to improve heatproofing of CNT electron sources by mixing boron into the Ag-CNT paste.","PeriodicalId":340787,"journal":{"name":"IVESC 2004. The 5th International Vacuum Electron Sources Conference Proceedings (IEEE Cat. No.04EX839)","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133644648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effect of sputtering bias on the properties of Nb-Si-N film","authors":"Jianfeng Wang, Z. Song, K. Xu","doi":"10.1109/IVESC.2004.1414234","DOIUrl":"https://doi.org/10.1109/IVESC.2004.1414234","url":null,"abstract":"Nb-Si-N films were sputtered by RF reactive magnetron sputtering with different bias voltages. The effect of sputtering bias on the properties of Nb-Si-N film was studied. Energy dispersive X-ray spectroscopy, atomic force microscope, X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, four-point probe method and microhardness tester were employed to characterize the microstructure and properties of the Nb-Si-N films. The results reveal that as the bias voltage increases the Nb/Si ratio and the surface roughness increase. The microstructure of Nb-Si-N films is the nano-composite structure with nano-sized NbN crystallites embedded in amorphous SiN/sub x/ phase. High sputtering bias is in favor of the growth of NbN grains in the Nb-Si-N film. As the bias increases the /spl epsiv/-NbN phase increases. The sheet resistance and microhardness of Nb-Si-N film also change as the bias varies. These phenomenons may be related with the /spl epsiv/-NbN phase in some degree.","PeriodicalId":340787,"journal":{"name":"IVESC 2004. The 5th International Vacuum Electron Sources Conference Proceedings (IEEE Cat. No.04EX839)","volume":"157 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131348240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preparation of impregnated barium scandate cathode and its application","authors":"Dingjian Jiang, Sikong Hong, Chenfeng Zhou, Dean Wang, Xueque Liu","doi":"10.1109/IVESC.2004.1414199","DOIUrl":"https://doi.org/10.1109/IVESC.2004.1414199","url":null,"abstract":"The paper introduces an impregnated barium scandate cathode, which uses scandium, barium, calcium, aluminum carbonates as emission materials which are impregnated into the tungsten matrix substrate directly. The preparation process is described. The cathode can be used not only to several types of microwave tubes successfully, but also to large demountable traveling wave linear accelerators reliably. The cathode can be activated, after exposure to air several times and still keeps its emission ability.","PeriodicalId":340787,"journal":{"name":"IVESC 2004. The 5th International Vacuum Electron Sources Conference Proceedings (IEEE Cat. No.04EX839)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130587414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of InP/InGaAs heterostructure confinement bipolar transistors grown by low-pressure MOCVD","authors":"J. Tsai, Ying-Cheng Chu, King-Poul Zhu, S. Chiu","doi":"10.1109/IVESC.2004.1414279","DOIUrl":"https://doi.org/10.1109/IVESC.2004.1414279","url":null,"abstract":"In this article, high-performance InP/InGaAs heterostructure confinement bipolar transistors, including a /spl delta/-doped heterojunction bipolar transistor (5-HBT) and superlattice-confinement bipolar transistor (SCBT), are successfully fabricated and demonstrated.","PeriodicalId":340787,"journal":{"name":"IVESC 2004. The 5th International Vacuum Electron Sources Conference Proceedings (IEEE Cat. No.04EX839)","volume":"290 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133141787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Field emission and other electron sources fabrication of dielectric layer in a novel triode structure CNT-fed","authors":"Qilong Wang, W. Lei, Zhu Zhua, Xiaobing Zhang, Y. Di, Jinchan Wang","doi":"10.1109/IVESC.2004.1414212","DOIUrl":"https://doi.org/10.1109/IVESC.2004.1414212","url":null,"abstract":"A new triode structure for printable carbon nanotube field emission displays is described in this paper. In the structure, silver paste is printed on the surface of a metal mesh and acts as the gate electrode. Between the gate and the metal mesh is a dielectric layer. MgO film and MgF/sub 2/ film are deposited on the surfaces of the mesh and the funnels by evaporation. A voltage applied on the metal mesh, the primary electrons emit from the CNT cathode and bombard on the surface of the metal mesh with initial energy. The secondary electrons and backscatters are generated. Because of the low energy of the secondary electrons, the gate can control the emission current easily. Therefore the range of the modulate voltage can be withdrawn. The dielectric layer on the surface of the metal mesh must be compact, otherwise silver paste will penetrate in after firing and under high voltage, breakdown of the insulator materials will occur by surface flashover. This paper reports the fabrication process of dielectric layer and the preparation of the materials.","PeriodicalId":340787,"journal":{"name":"IVESC 2004. The 5th International Vacuum Electron Sources Conference Proceedings (IEEE Cat. No.04EX839)","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132170812","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimization of dispenser cathode","authors":"O. Kultashev, N.M. Ogoleva","doi":"10.1109/IVESC.2004.1414198","DOIUrl":"https://doi.org/10.1109/IVESC.2004.1414198","url":null,"abstract":"The problem of optimization of emission properties of industrial thermionic dispenser cathodes is lying in its complexity and difficulty of experimental identification of elemental processes and structural aspects of the cathode technology and its usage. As a rule the functioning of most efficient barium-oxygen molecular layer cathodes is looked upon only as a process of supplying of the cathode surface with barium atoms needed for the maintenance of the Ba-O-Ne layer by the Knudsen flow through the cathode body pores without due attention to the questions of BaO or O movement via surface migration and possible chemical reactions on the cathode surface and in the cathode volume. In the present report we try to widen means of model understanding of the processes by using of an approach consisted in computer simulation of the main processes taking place in the volume and the surface of the cathode. In the report will be presented results of studying the dynamic equilibrium between the surface layer composition and the main branches of the particle flow; the Knudsen flow and the particle surface migration processes as well as the possibility of chemical reactions taking place parallely. One of the main conclusions of this study is that the Knudsen flow coexisting with surface migration in a simple system as parallel transport agents can not raise the delivery of adsorbing atoms to the cathode surface and only leads to deterioration of its emission properties and the working life.","PeriodicalId":340787,"journal":{"name":"IVESC 2004. The 5th International Vacuum Electron Sources Conference Proceedings (IEEE Cat. No.04EX839)","volume":"125 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124661654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}