Electron Emission from Nanodiamond Field Emitters

Chemical vapor deposited (CVD) diamond is an attractive material for electron field emitters because of its low or negative electron affinity, excellent mechanical strength, and chemical inertness. Diamond’s excellent mechanical strength and chemical stability contribute to excellent durability characteristics. The strong covalent sp3 bonds present in diamond have a stabilizing effect on the electron emission as compared to the weaker ionic bonds present in traditional metal cathodes. Nanocrystalline diamond, (grain size ~ 1 nm - 100 nm), possesses unique properties including deliberate and controlled amounts of sp2-carbon content and n-type electrical conductivity at room temperature.<br/><br/>The authors have demonstrated electron emission from widely spaced nanodiamond pyramidal tip arrays as well as lateral lithographically-patterned field emission arrays. Array tips have not been observed to be physically damaged by extended emission tests on the scales available to scanning electron microscopy (SEM). Methods developed by the authors permit analysis of diamond tip structure and provide a basis for optimization of field emitter composition and performance.<br/><br/>The authors are focused on developing new technologies, sensors and products for operation in extreme environments and applications (e.g., high and low temperature, pressure, radiation, etc.) where no other, or limited, capability currently exists.