GaN-Based Light-Emitting Diodes on Electrochemically Etched ${\rm n}^{-}$ -GaN Template

We report the fabrication of GaN-based light-emitting diodes (LEDs) with embedded reshaped ellipsoidal voids using an electrochemically etched n^--GaN template. It is found that the size of the reshaped ellipsoidal voids is strongly related to the initial diameter of the horizontal/tree-branch-like pores in the n^--GaN and the bias of electrochemical etching. It is also found that the forward voltage of the LEDs on such templates does not increase drastically. The reverse leakage current, however, increases with increasing electrochemical etching bias of the n^--GaN template. Furthermore, it is found that light output power at 20 mA is 50% higher for such LEDs, as compared with conventional LEDs.