工作职能
热离子发射
钻石
分析化学(期刊)
化学气相沉积
场电子发射
电子亲和性(数据页)
电子
化学
人造金刚石
兴奋剂
原子物理学
氢
材料科学
光电子学
电极
物理
复合材料
物理化学
量子力学
色谱法
有机化学
分子
作者
Franz Koeck,R. J. Nemanich,Andrada Lazea‐Stoyanova,Ken Haenen
标识
DOI:10.1016/j.diamond.2009.01.024
摘要
Thermionic electron emitters are a key component in applications ranging from travelling wave tubes for communications, space propulsion and direct energy conversion. As the conventional approach based on metallic emitters requires high operating temperatures the negative electron affinity (NEA) characteristic of diamond surfaces in conjunction with suitable donors would allow an electronic structure corresponding to a low effective work function. We have thus prepared phosphorus-doped polycrystalline diamond films on metallic substrates by plasma assisted chemical vapor deposition where an NEA surface characteristics was induced by exposure of the film surface to a hydrogen plasma. Thermionic electron emission measurements in an UHV environment were conducted with respect to the Richardson–Dushman relation observing an emission current at temperatures < 375 °C. Measurements were terminated at 765 °C without significant reduction in the electron emission current indicating a stable hydrogen passivation of the diamond surface. A fit of the emission data to the Richardson equation allowed for the extraction of emission parameters where the value of the materials work function was evaluated to 0.9 eV. This value could well be the lowest measured work function of any known material.
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