Photoluminescence, electrical and mechanical properties of ultra-long single crystalline Al4O4C nanowires

Ultra-long single-crystalline orthorhombic Al4O4C nanowires (NWs) were synthesized via annealing a mixture of Ta, Al, and graphite powders at 1500 °C for 1 h in a flowing argon atmosphere based on the vapor-liquid-solid (VSL) mechanism. The molten Al-Ta droplets formed by adding Ta resulted in its growth along the [101] direction. Therefore, highly crystalline Al4O4C NWs possessed rough surfaces, a high aspect ratio (∼2200) with diameters ranging from 100 nm to 500 nm and lengths up to hundreds of micrometers (660 μm). They exhibited a decreased bandgap of 2.63 eV and broad emission bands in yellow/near-infrared light region under the excitation of 532 nm, which was originated by Ar doping and surficial defects. Furthermore, the single nanowire electrode devices were fabricated using the FIB-SEM technique to accurately measure the electrical and mechanical properties. Al4O4C NWs possessed the intrinsic resistivity of 202.61 Ω·m, Young's modulus of 93.89 ± 13.34 GPa, and yield strength of 4.08 ± 0.51 GPa, and therefore it is potential for nanodevice applications.