纳米AgSnO_2/Bi_2O_3触头材料的性能及导电机理研究

Study on Properties and Conductive Mechanism of Nano AgSnO_2/Bi_2O_3 Contact Materials

添加少量第三种元素的AgSnO_2触头材料的电性能研究均处在试验阶段而未深入到理论研究阶段。本文采用溶胶-凝胶法制备纳米级AgSnO_2/Bi_2O_3触头材料,材料的密度为9.73 g/cm3、硬度为105.35HV、电导率为70.22%IACS,并且接触电阻较小。在掺杂Bi元素提高触头材料性能的基础上,进行导电机理的研究。从微观原子角度采用第一性原理的计算方法,计算了Bi掺杂SnO_2的电子结构、能带图、态密度及电荷密度分布。结果表明,Bi掺杂后带隙减小,电子跃迁容易,同时费米面附近载流子浓度增大,增强了材料的导电性。最终得出添加少量Bi元素能够使得AgSnO_2触头材料的导电性增强的机理。

The electrical properties of AgSnO2 contact material with a small amount of the third element are in the experimental stage, but no theoretical reports were reported. Nano AgSnO2/Bi203 contact materials were prepared by sol-gel method. The density of the contact material is 9.73 g/cmz , hardness is 105.35HV, conductivity is 70.22% IACS, and the contact resistance is smaller. On the basis of doping Bi can improve the properties of contact materials, the conductive mechanism was studied. The results show that the band gap becomes smaller, the electronic transitions easily, and the carrier concentration near Fermi level increases after Bi doping, which made the conductivity of the material enhanced. Finally, the mechanism of enhancing the electrical conductivity of AgSnO2 contact materials by adding a small amount of Bi elements was obtained.