Physical characterization of diamond pyramidal microtip emitters

Micro patterned diamond pyramidal tips have demonstrated high emission current. This paper presents the physical analyses that have proceeded to characterize the topology, morphology and microstructure of these diamond microtips using transmission electron microscopy, atomic force microscopy, scanning tunneling microscopy, and Raman spectroscopy. The results show that the diamond microtips are indeed a polycrystalline diamond structure as evidenced by Raman spectroscopy and diffraction analysis of the TEM. AFM and STM results provide detailed information as to the surface and tip shape of the diamond emitters. AFM/STM observations suggest a nucleation and growth process whereby the manner in which CVD diamond nucleates on the planar top surface of the tip substrate is distinct and different from the way the diamond grows in the cavity "mold". Further, the TEM results contrast the diamond microstructure in the field area with that of the tip where distinct differences are observed.