Enhanced performance of vertical GaN-Based light-emitting diodes with a current-blocking layer and electroplated nickel substrate

The performance of vertical-structure metallic-substrate GaN-based light-emitting diodes (VM-LEDs) with a patterned SiO₂ film as the current-blocking layer (CBL) was investigated. From theoretical calculations of current and light distributions and experimental results on current-voltage (I-V) and light output power-current (L-I) characteristics, we found that SiO₂ CBL inserted under the n-pad electrode increases light output power by 35.4% at 20mA as compared with VM-LEDs without CBL. Such an improvement is attributed to the insulated CBL structure, which provides better current spreading and less photon absorption and/or reflection at the n-electrode.