Fabrication, characterization, and mechanism of vertically aligned titanium nitride nanowires

► Titanium nitride (TiN) nanowires have been grown on single crystal magnesium oxide substrates using a bottom-up pulsed laser deposition method where Ti-N based gaseous reactants in the laser plume supersaturate the catalytic gold liquid located on the substrate surfaces. ► This bottom-up approach gives rise to a one-dimensional TiN nanowire structure (length: 200-300 nm and diameter: 20-30 nm) capped with a catalytic Au seed. ► The ascent of Au nanodots to the top of TiN nanowires can be explained based bond-strengths of Ti-O (672 kJ/mol), Ti-N (496 kJ/mol), Au-N (416 kJ/mol), and Au-O (221 kJ/mol) bonds. ► The TiN nanowires were provided vertical alignment by selecting a plane of the substrate that provides the least lattice mismatching to the (1 1 1) plane of TiN which has lower surface energy than its other planes: (1 0 0) or (1 1 0).