Enhanced light output of vertical GaN-based LEDs with surface roughened by SiO₂ nanotube arrays

The fabrication of SiO₂ nanotube (SiO₂ -NT) arrays and their promising application in improving light extraction of vertical structure GaN-based light emitting diodes (LEDs) are proposed. Compared to regular vertical-conducting light emitting dioded (VLEDs), the proposed VLEDs with SiO₂ -NT arrays (2-3 μm in length) show increases in light output power (Lop) by 49.8-60.4% at 350 mA. In comparison to VLEDs with ZnO nanowire arrays having the same the dimension, enhancement of 12.3-22.9% in Lop has been achieved from the proposed devices. These improvements could be attributed to the use of SiO₂ -NT arrays that not only boost the angular randomization of emitted photons but also enhance light transmission from the waveguiding effect.