  A high-current annealing technique is used to fabricate nanogaps and hybrid
diamond/graphite structures in boron-doped nanocrystalline diamond films.
Nanometer-sized gaps down to 1 nm are produced using a feedback-controlled
current annealing procedure. The nanogaps are characterized using scanning
electron microscopy and electronic transport measurements. The structural
changes produced by the elevated temperature, achieved by Joule heating during
current annealing, are characterized using Raman spectroscopy. The formation of
hybridized diamond/graphite structure is observed at the point of maximum heat
accumulation.
