GaN-based light-emitting diodes with a thermally stable mirror structure underneath an insulating sio2 layer

This study reports the development of GaN-based light-emitting diodes (LEDs) with Ni/Ag (1 nm 0.2 nm/100 nm 2 nm) layers underneath an insulating layer of SiO₂. The results of this study confirm the thermal stability of a Ni/Ag mirror with reflectance of 90.6±1.5± following thermal annealing at 500±C for 5±min. This approach achieves far superior current spreading and prevents the absorption of light through the use of an opaque p-pad electrode. With 20-mA current injection, the output power of the LED with SiO₂/Ni/Ag layers was 6.5 and 12.1% greater than that of LEDs with and without a SiO₂ layer, respectively. Furthermore, the 20-mA forward voltage increased only slightly from 3.03±0.01 to 3.05±0.01±V for LEDs with SiO₂/Ni/Ag layers. Good reliability is also achieved for LEDs with SiO₂/Ni/Ag layers.