金属过渡层增强金刚石薄膜场发射性能的机理研究

Study on the Mechanism of Improving Field Emission Properties of Diamond Films by Metal Transition Layers

摘要:

以金属钛和钨为过渡层,采用PE-HFCVD法在硅基上制备金刚石薄膜,并对薄膜的场发射特性分析研究。结果表明,金属过渡层对金刚石薄膜场发射性能有显著的增强作用。以金属钨为过渡层时,金刚石薄膜的场发射开启场强为5.4 V/μm,比无过渡层降低了44%；场发射电流密度在电场强度为8.9 V/μm时达到1.48 mA/cm₂。通过对薄膜的结构表征知,场发射性能的增强主要与界面处电子运输势垒的降低及薄膜中sp₂ C含量的增加有关,在界面处及金刚石膜内形成良好的导电通道,使电子更容易运输至薄膜表面,从而表现出优异的场发射性能。

Abstract:

The titanium and tungsten were used as the transition layer respectively, the mirco-crystalline diamond films on a silicon substrate were prepared by PE-HFCVD method. The field emission characteristics of the films were studied in this paper. The results show that, the metal transition layers can significantly enhance the field emission properties of the diamond films. When the transition layer is tungsten, the opening field intensity of the diamond film is 5.4 V/μm, which reduces by 44% compared with non-transition layer ; while the field emission current density can reach 1.48 mA/cm₂ when the electric field intensity is 8.9 V/μm. The structure characterization of the films show that, The enhancement of the field emission properties is mainly attributed to the decrease of the electron transport barrier at the interface and the increase of the sp₂ C content in the film. The formation of good conductive channels at the interface and the diamond film make the electron more easy to transport to the film surface. Hence, the diamond films which use metal transition layers show excellent field emission properties.