On the dendritic growth and field emission of amorphous AlQ3 nanowires

Amorphous AlQ3 nanowires were fabricated by vapor condensation under a cold trap. Their diameter distributed in a small range of 35–60 nm, but their length was dramatically changed by working pressure. Longer and thinner nanowires could be obtained at a lower working pressure. The most appropriate condition to fabricate long and fine nanowires was to set boat temperature at 410 °C and to control the working pressure of Ar at 1.33 × 103–3.99 × 103 Pa. A higher density of nanowires was observed at a lower working pressure. The dendritic growth mechanism caused by a temperature gradient was proposed to explain the formation of branched nanowires. Due to the absence of quantum confinement effect, the nanowires did not exhibit a PL blue shift as their sizes shrank. When higher density of nanowires were formed at a lower working pressure, stronger PL intensity could be revealed on the emission spectra. The amorphous nanowires also exhibited field-emission behavior. Their Eturn-on ranged from 3 to 20 V/μm and frequently approximated to 10 V/μm, comparable to those of most inorganic 1D nanostructures but somewhat larger than that of CNTs. Larger thickness caused by a higher deposition rate at a higher boat temperature could lead to a smaller Eturn-on.