Nanostructured interior of laser-induced wires in diamond

The paper considers the internal structure and electrical properties of conductive wires formed inside single crystal diamond by picosecond laser pulses under different processing conditions. Mechanically polished high-quality longitudinal sections of the wires were carefully examined using scanning electron microscopy, scanning spreading resistance microscopy, and Raman spectroscopy. It has been found that the interior of the wires consists of ~150-nm-thick sp2 sheets forming a conductive network inside the original diamond matrix. The sp2 sheets are clustered in segments distributed quasi-periodically along the wire. Both the velocity of the laser focus translation and the pulse energy have been found to influence the thickness of the sp2 sheets and spatial arrangement of the segments. The relationship between the internal structure of the wires and their integrated resistivity is discussed. [Display omitted] •Only part of diamond transforms into graphite in laser-irradiated diamond.•Interior of wires contains the sp2 nanosheets separated by diamond areas.•The higher the segment period, the lower the resistivity of the wires.