Physical properties of the electrical barriers in varistors
Physical properties of the electrical barriers in varistors
复制标题
压敏电阻中电势垒的物理特性
DOI：
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发表时间：
1976
期刊：
影响因子：
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通讯作者：
W. Morris
中科院分区：
文献类型：
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作者：
W. Morris
氧化锌压敏电阻器中电流和电压之间的非线性关系是由多晶陶瓷中晶界处的电势垒引起的。在非常低的电场下，肖特基发射占电流的大部分，随着电场的增加，肖特基发射变得更加重要，并有助于降低势垒。在高场存在下，通过势垒的隧穿占主导地位，从而产生高度非线性行为。铋（氧化物）在晶界偏析发生在两种形式：吸附层存在于晶粒之间的界面上，和离散相，这是连续沿着晶粒边缘。后者呈三棱柱的形式，当它们接近ZnO-ZnO界面时表现出约60°的二面角，因此该相不完全润湿ZnO晶粒。吸附层可以解释电势垒。俄歇电子分析表明其化学厚度小于50埃。一个耗尽层是...
The nonlinear relationship between current and voltage in the zinc oxide varistor arises from electrical barriers at the grain boundaries in the polycrystalline ceramic. At very low fields, thermionic emission accounts for the majority of the current, with Schottky emission becoming more important as the field increases and assists in lowering the barrier. Tunneling through the barrier dominates in the presence of high fields, giving the highly nonlinear behavior. The bismuth (oxide) which segregates at the grain boundries occurs in two forms: an adsorbed layer present on the interfaces between grains, and a discrete phase which is continuous along grain edges. The latter is in the form of triangular prisms which exhibit a dihedral angle of about 60° as they approach a ZnO–ZnO interface, and thus this phase does not completely wet the ZnO grains. The adsorbed layer can account for the electrical barrier. Its chemical thickness is less than 50 A as determined by Auger electron analysis. A depletion layer i...