GaN-based LEDs output power improved by textured GaN/Sapphire interface using in situ SiH₄ treatment process during epitaxial growth

In this study, we demonstrate an in situ roughening technique at the GaN/sapphire interface in GaN-based LEDs using a silane treatment SiH ₄ treatment) process that forms a thin SiN_x layer with nanometer-sized holes on the sapphire surface that behave like a patterned sapphire substrate. A plurality of voids at the GaN/sapphire interface is observed according to the transmission electron microscopy analysis. With a 20 mA current injection, the results indicate that the typical output power of LEDs grown with and without the SiH₄ treatment process are approximately 18.0 and 15.6 mW, respectively. In other words, the output power can be enhanced by 15% with the use of the SiH₄ treatment process. The enhancement of output power is mainly due to light scattering at the naturally textured GaN/sapphire interface, which can lead to a higher escape probability for the photons emitted from the active layer in an LED.