逸出功的某些特性
SOME PROPERTIES OFTHE WORK FUNCTION
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摘要: 在實用熱陰極中,測量得的發(fā)射常數(shù)值經(jīng)常小于120A/cm2T2。這是由于逸出功有一分布所致,而不是由于電子遇到表面勢壘時的反射。用單晶面測量時,理論和實驗值便相符了。事實上發(fā)射來源于已穿透進勢壘的表面電子。這些電子既不能進入真空,也不能在金屬導帶中自由運動,否則不同晶面便不可能有不同的逸出功。異族元素的吸附增加表面電子的數(shù)目和能量,因而使逸出功下降。
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關(guān)鍵詞:
- 熱陰極; 逸出功; 發(fā)射常數(shù); 表面勢壘; 表面電子
Abstract: that for practial emitters the measured values of the constant in Richardson's equation are always less than 120 A/cm2T is due to the nonuniformity of work function not to the reflection of electron at the surface potential barrier. For monocrystal faces, the measured and theoretical values agree. In fact, emission comes from those surface electrons already penetrated into the potential barrier before excitation. These furface electrons can neither move freely through vacuum non through conduction band of the metal, otherwise different crystal faces would not have different work functions. The adsorption of foreign atoms increases the energy and number of the surface electron and then lowers the work function. -
В.С.Фоменко,эмиссионные свойства ма териалов,Справочник,Киев,Наукова Думка,1981.[2]D. Jones, D.Mcneely, L. W. Swanson, Applications of Surf. Sci., 2 (1979), 232.[3]劉學愨,陰極電子學,科學出版社,1980.[4]G. A. Hass, R. E. Thomas, Surf Sci., 4 (1966), 64.[5]卞彭,電子學通訊,1977年,總39期,第10頁.[6]曾海山,楊凌云,葉毓林,電子科學學刊,10(1988)2, 167-175.[7]王寧,王鼎蓋,電子科學學刊,8(1986)6, 408-415. -
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