A nanorods AlN layer prepared by sputtering at oblique-angle and application as a buffer layer in a GaN-based light-emitting diodes

We presents a nanorods AlN films on sapphire substrate deposited at oblique-angle by a radio-frequency reactive magnetron sputtering. A nanorods AlN layer was employed as a buffer layer for a GaN-based LEDs to improve optoelectronic characteristics of LEDs. The diameter of the nanorods AlN buffer layer is in the range of 30-50 nm. Typical current-voltage characteristics of the GaN-based LEDs with a nanorods AlN buffer layer have a forward-bias voltage of 3.1 V at an injection current of 20 mA. The output intensity of LEDs initially increases linearly as the injection current increases from 10 mA to 150 mA. The light output power of the GaN-based LED with a nanoporous AlN layer was about 31% higher than that of a GaN-based LED without a nanoporous AlN layer at an injection current of 250 mA.