为解决电子倍增器、场发射阴极和粒子/光子探测器现有阴极材料次级发射系数低且发射不稳定的问题,对微波等离子体化学气相沉积(Microwave Plasma Chemical Vapor Deposition,MPCVD)法结合H等离子体表面处理工艺制备的不同B2H6/CH4浓度...为解决电子倍增器、场发射阴极和粒子/光子探测器现有阴极材料次级发射系数低且发射不稳定的问题,对微波等离子体化学气相沉积(Microwave Plasma Chemical Vapor Deposition,MPCVD)法结合H等离子体表面处理工艺制备的不同B2H6/CH4浓度的硼掺杂金刚石薄膜的次级发射能力进行了研究。样品表面扫描电子显微镜和拉曼光谱分析结果显示,硼掺杂金刚石膜表面形貌与未掺杂的金刚石膜相似,样品表面均为高纯度的金刚石相。将置于空气中数日且未经任何表面处理的硼掺杂金刚石样品进行次级电子发射性能测试,结果显示一次电子入射能量为1keV时,得到高达18.3的二次电子发射系数。试验证实这种具有高二次电子发射系数的硼掺杂金刚石膜,暴露空气中由于表面氧化会破坏其表面的负电子亲和势,而真空中加热会使表面重新恢复负电子亲和势,这种负电子亲和势的完整保留,提高了该材料次级发射的稳定性,在器件中具有重要的应用前景。展开更多
Discharge branching is a general phenomenon in atmospheric-pressure air,dense gases,and two-phase mixtures(TPMs).In this work,an ultraviolet imaging device is utilized to investigate the branching of positive pulsed d...Discharge branching is a general phenomenon in atmospheric-pressure air,dense gases,and two-phase mixtures(TPMs).In this work,an ultraviolet imaging device is utilized to investigate the branching of positive pulsed discharges in TPMs.Comparison among the captured images indicates that the branching is caused by the voltages and the macropartilces in the discharge channels combining together.The interaction of macroparticles with ions,electrons or photons is one reason for the branching behavior of pulsed discharges.The generation of electrons at the discharge front closely relates to the work function of dielectric macroparticles,which is a key parameter influencing the electron-emission ability of macroparticle surfaces.The electric field alteration under various applied voltage in TPMs,which is calculated by a two-dimension finite element method,is the other reason for the guiding effect of macroparticles on the streamers compared with in the air.展开更多
文摘为解决电子倍增器、场发射阴极和粒子/光子探测器现有阴极材料次级发射系数低且发射不稳定的问题,对微波等离子体化学气相沉积(Microwave Plasma Chemical Vapor Deposition,MPCVD)法结合H等离子体表面处理工艺制备的不同B2H6/CH4浓度的硼掺杂金刚石薄膜的次级发射能力进行了研究。样品表面扫描电子显微镜和拉曼光谱分析结果显示,硼掺杂金刚石膜表面形貌与未掺杂的金刚石膜相似,样品表面均为高纯度的金刚石相。将置于空气中数日且未经任何表面处理的硼掺杂金刚石样品进行次级电子发射性能测试,结果显示一次电子入射能量为1keV时,得到高达18.3的二次电子发射系数。试验证实这种具有高二次电子发射系数的硼掺杂金刚石膜,暴露空气中由于表面氧化会破坏其表面的负电子亲和势,而真空中加热会使表面重新恢复负电子亲和势,这种负电子亲和势的完整保留,提高了该材料次级发射的稳定性,在器件中具有重要的应用前景。
基金Project supported by National Natural Science Foundation of China(50237010),National Basic Research Program of China(973 Program)(2011CB209400)
文摘Discharge branching is a general phenomenon in atmospheric-pressure air,dense gases,and two-phase mixtures(TPMs).In this work,an ultraviolet imaging device is utilized to investigate the branching of positive pulsed discharges in TPMs.Comparison among the captured images indicates that the branching is caused by the voltages and the macropartilces in the discharge channels combining together.The interaction of macroparticles with ions,electrons or photons is one reason for the branching behavior of pulsed discharges.The generation of electrons at the discharge front closely relates to the work function of dielectric macroparticles,which is a key parameter influencing the electron-emission ability of macroparticle surfaces.The electric field alteration under various applied voltage in TPMs,which is calculated by a two-dimension finite element method,is the other reason for the guiding effect of macroparticles on the streamers compared with in the air.
