金属过渡层增强金刚石薄膜场发射性能的机理研究

Improvement Mechanism of Field Emission Properties of Diamond Films by Metal Transition Layers

以金属钛和钨为过渡层,采用HFCVD法在硅基上制备金刚石薄膜,并对薄膜的场发射特性进行分析研究。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5.4V/μm,比无过渡层降低了44%;场发射电流密度在电场强度为8.9V/μm时可达到1.48mA/cm^2。通过对薄膜结构表征可知,场发射性能增强主要与界面处电子运输势垒的降低及薄膜中sp^2 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。

Micro-crystalline diamond films on a silicon substrate were prepared by a HFCVD method with a titanium or tungsten transition layer,and the field emission characteristics of the films were studied.The results show that the metal transition layers can significantly enhance the field emission properties of the diamond films.When the tungsten layer is used as the transition layer,the opening field intensity of the film is 5.4 V/μm,which is reduced by 44% compared with that of non-transition layer films.Furthermore,the field emission current density can reach 1.48 mA/cm^2 at the electric field strength of 8.9 V/μm.The structure characterization of the films shows that the enhancement of the field emission properties is mainly attributed to the decrease in the electron transport barrier at the interface and the increase in the sp^2 C content in the film.Good conductive channels are formed at the interface and in the diamond film,causing easier electron transport.Hence,the diamond film with a metal transition layer exhibits enhanced field emission properties.