Enhanced light output power in InGaN/GaN light-emitting diodes with a high reflective current blocking layer

The light output power of an InGaN/GaN light-emitting diode is improved by using a SiO;/TiO;distributed Bragg reflector（DBR） and an Al mirror as a hybrid reflective current blocking layer（CBL）.Such a hybrid reflective CBL not only plays the role of the CBL by enhancing current spreading but also plays the role of a reflector by preventing photons near the p-electrode pad from being absorbed by a metal electrode.At a wavelength of 455 nm,a 1.5-pair of SiO;/TiO;DBR and an Al mirror（i.e.1.5-pair DBR+Al） deposited on a p-GaN layer showed a normal-incidence reflectivity as high as 97.8%.With 20 mA current injection,it was found that the output power was 25.26,24.45,23.58 and 22.45 mW for the LED with a 1.5-pair DBR+Al CBL,a 3-pair DBR CBL,SiO;CBL and without a CBL,respectively.