Temperature-dependent photoluminescence and electron field emission properties of AlN nanotip arrays

Large-scale single-crystalline AlN nanotip arrays have been fabricated via a facile catalysis-free approach using AlCl3 powder and NH3 as starting materials. These nanotips exhibit an intense broad ultraviolet emission centered at 3.28 eV. The field emission features a notable electron current with a low turn-on field. The turn-on and threshold electric field are found to decrease substantially from 7.7 to 3.9 V/μm and 7.9 to 4.1 V/μm, respectively, while the estimated field enhancement factor increases from 483 to 1884 with increasing the ambient-temperature from room temperature to 573 K. The dependence of the photoluminescence and electron field emission with temperature and the possible mechanism involved has systematically been investigated and thus discussed.