Enhancement of Light Output Power of GaN-Based Light-Emitting Diodes by a Reflective Current Blocking Layer

Abstract

In this study, a GaN-based light-emitting diode (LED) with a distributed Bragg reflector (DBR) current blocking layer (CBL) beneath the p-pad electrode is demonstrated. A high reflectivity DBR structure is composed of five periods SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> and TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> layers. At a driving current of 20 mA, the light output power of the LEDs with DBR CBL was 16.8% and 11.3% higher than the LEDs without and with SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> CBL. The improvement is contributed to the DBR CBL can deflect the current away from the p-electrode pad and also prevent the light absorption by the opaque metal electrode. It was found that LEDs with DBR CBL shows better current spreading and broader far-field pattern.