Effect of the Electrode Pattern on Current Spreading and Driving Voltage in a GaN∕Sapphire LED Chip

Abstract

The effects of p- and n-electrode patterning on the current spreading and driving voltage of a side-view GaN∕sapphire light-emitting diode (LED) chip are investigated via a numerical simulation. The numerical results (current distributions) for the striped pattern p-electrode are well consistent with the optical emission patterns taken from emission images. A desirable uniformity of the current distribution in the active layer can be obtained by the appropriate arrangement of p- and n-electrode patterns. At the same time, a lower voltage drop in the LED chip is also obtained due to a more uniform current distribution in the p-GaN layer and a smaller overall distance for current movement in the n-GaN layer. With an injection current of , a decrease in driving voltage of 13% for well-designed electrode patterns can achieve compared to the control devices considered in this study.