  Ultrafast laser micromachining can be used to promote diamond graphitisation,
enabling the creation of electrically conductive wires embedded in the diamond
matrix. In this context, the presence of a potential barrier in the
conductivity of transverse graphitic wires fabricated by pulsed Bessel beams
without sample translation across 500 {\mu}m thick monocrystalline CVD diamond
has been studied. In particular, the role of the crystallographic orientation
has been analysed. The morphology and the conductivity of the obtained
electrodes have been studied using optical microscopy and current-voltage
measurements, while the structural changes have been investigated by means of
micro-Raman spectroscopy. By using different laser writing parameters, we have
explored the features of different electrodes in a (100) and a (110) oriented
diamond crystal respectively. We show that in addition to the use of specific
pulse energies and durations (in the fs and ps regimes), the crystallographic
orientation of the sample plays an important role in reducing or eliminating
the potential barrier height of the IV electrical characterization curves. In a
(110) oriented sample, it is possible to eradicate the potential barrier
completely even for graphitic wires fabricated at low pulse energy and in the
fs pulse duration regime, in contrast to the (100) oriented-crystal case where
the barrier is generally observed.
