氧化锌/银双层膜负反馈阴极电极的制备及性能研究

Research on Preparation and Characteristics of ZnO/Ag Bilayer Negative Feedback Cathode Electrode

提出了一种可显著改善碳纳米管(CNTs)场致发射性能的ZnO/Ag双层膜负反馈阴极电极的制备方法.在条形银电极上溅射沉积一定厚度的Zn膜,经热氧化和湿法刻蚀制备成ZnO/Ag双层膜电极.同单层的Ag或氧化铟锡电极相比,该电极不仅具有足够的负反馈电阻(限流电阻)阻止CNTs场发射中过流的发生,而且降低了条形阴极电极的线性电阻,确保了场发射的均匀性.当溅射沉积Zn膜的厚度从40 nm增到120 nm时,热氧化形成的ZnO由孤岛状的颗粒变为连续体的薄膜,ZnO/Ag双层膜电极的表面光洁度比单层的Ag电极有很大的提高,负反馈电阻层的电阻增大,负反馈的能力增强.CNTs薄膜阴极场发射特性曲线证明,ZnO/Ag双层膜电极能明显降低场发射电流的波动,有效提高器件的稳定性和寿命.

A preparation method of ZnO/Ag bilayer negative feedback cathode electrodes was proposed, which can remarkably improve the field emission properties of carbon nanotube （CNT） films. Direct current magnetron sputtering was adopted to deposit Zn film on strip sliver electrodes, and then thermal oxidizing and wet etching were employed to fabricate ZnO/Ag bilayer strip electrodes. Compared to monolayer electrodes of silver and indium tin oxide, the bilayer electrode not only possesses adequate negative feedback or limiting-current resistance to suppress over-current, but also induces the linear resistance to ensure luminescence uniformity. When the thickness of as-deposited Zn layer increased from 40 nm to 120 nm, the morphology of thermal oxidizing ZnO changed from islanded grains to continuous film. Thus, the ZnO/Ag bilayer electrode has smoother surface than sliver electrode. The limiting-current resistance was increased and the negative feedback ability was enhanced. The field emission characteristics of CNT film cathode prove that the ZnO/Ag bilayer electrode can decrease the fluctuation of CNT field emission current, and improve device stability and lifetime effectively.