高反射性电流阻挡层用于提高InGaN/GaN发光二极管的光输出功率

由SiO₂/TiO₂分布布拉格反射镜(DBR)和Al镜组成的混合式反射电流阻挡层用于提高InGaN/GaN发光二极管的光输出功率。混合式反射电流阻挡层不仅增强了电流扩展效应而且有效的将射向p金属电极的光子反射防止其对p电极焊点附近光子的吸收。实验结果表明,淀积在p-GaN上1.5个周期的SiO₂/TiO₂DBR和Al镜在455nm垂直入射时的反射率高达97.8%。在20mA的工作电流下,与没有电流阻挡层的发光二极管相比,生长1.5对SiO₂/TiO₂ DBR和Al镜作为电流阻挡层的发光二极管的光输出功率提高了12.5%,且光输出功率的分布更加均匀。

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

The light output power of InGaN/GaN light-emitting diode (LED) is improved by using a SiO₂/TiO₂ 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 which enhances current spreading but also plays the role of a reflector which prevents photons near the p-electrode pad from being absorbed by metal electrode. At the wavelength of 455nm, 1.5-pair of SiO₂/TiO₂ DBR and Al mirror (i.e. 1.5-pair DBR Al) deposited on the 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 1.5-pair DBR Al CBL, 3-pair DBR CBL, SiO₂ CBL and without CBL, respectively.