Electrical conductivity of double textured black diamond films from RT to 800 K

Black diamond films represent examples of defect-engineered materials with enhanced optical and photoelectronic properties for applications at high temperatures and in harsh environments. Up to now, no scientific study about the electronic transport properties in the dark on the treated side has been reported as a function of temperature. Experimental results highlight that double-textured black diamond samples, obtained by two successive laser treatments along each orthogonal direction of diamond substrates, have electric transport characterized by two activation energies. The first one is responsible for the room-temperature conduction, with values comparable to the thermal energy at 300 K (tens of meV) and the second one appearing around 550 K, with values ranging from 0.45 of eV to almost 1.74 eV in the different samples. Interestingly, as the fraction of accumulated fluence released during the first of the two treatments decreases, the activation energy at high temperature of the samples increases, as well as the instability of electric conductivity after thermal annealing, that in turn induces a decrease of all the activation energies down to about 0.3-0.4 eV