Electrical-efficiency analysis of GaN-based light-emitting diodes with interdigitated-mesa geometry

We propose a novel method to analyze the current-voltage (I-V) characteristics of GaN-based light-emitting diodes (LEDs) with different p-type electrode-mesa geometries. The electrical efficiency is analyzed by calculating the electric field under the quasi-coplanar electrodes of GaN-based LEDs. The experimental results for GaN-based LEDs of chip sizes of 350 x 350 *mm2 and 1,000 x 1,000 *mm2 with interdigitated fingers are compared. A good agreement is obtained between the experimental and theoretical electrical efficiency of the GaN LEDs with a chip size of 1,000 x 1,000 *mm2. The current-crowding effect is analyzed by measuring the electroluminescence spectra of the devices. The result indicates that the current-crowding effect is largely reduced by increasing the number of interdigitated fingers. The electrical efficiency of a LED with a chip size of 1,000 x 1,000 *mm2 can be also enhanced by increasing the number of interdigitated fingers, showing the advantages of GaN LED with interdigitated-mesa geometries.