EFFECT OF SP(2) CONTENT AND TIP TREATMENT AN THE FIELD-EMISSION OF MICROPATTERNED PYRAMIDAL DIAMOND TIPS

Electron field emission characteristics of uniformly constructed micro -pyramids of polycrystalline diamond with varying sp(2) content have b een systemically investigated. Concurrently, tip surface treatment was performed and emission characteristics of the post-treated tips were evaluated. The experimental results show that the held emission charac teristics of the diamond can be enhanced by increasing the sp(2) conte nt and performing surface treatment. The emission current is significa ntly improved and the turn-on electric held is drastically reduced. Hy potheses are proposed for the effect of sp(2) content and surface trea tment on the field emission enhancement of diamond tips: (i) lowering of the work function due to sp(2) defect induced band and impurity des orption, and (ii) increase in field enhancement factor due to sp(2)-di amond-sp(2) microstructures and a field forming process. Analysis of t he experimental results indicates that (ii) is the more probable expla nation. (C) 1998 American Vacuum Society. [S0734-211X(98)08402-9].