Enhanced Light Output Power of GaN-Based Vertical Light-Emitting Diodes by Using Highly Reflective ITO-Ag-Pt Reflectors

Highly reflective and thermally stable indium-tin-oxide (ITO)-Ag-Pt p-type reflectors for use in high-performance GaN-based light-emitting diodes (LEDs) have been investigated. The specific contact resistance of the ITO-Ag-Pt contacts was found to be 7.2 ×10 -5 Omegamiddotcm 2 . The ITO-Ag-Pt contacts showed a higher reflectance after thermal annealing (82% at 460 nm), while the reflectance of the ITO-Ag contacts was reduced from 81% to 65%. In addition, surface agglomeration was drastically decreased, indicating that the Pt layer efficiently prevents the surface agglomeration of the Ag layer. The vertical LEDs (VLEDs) fabricated with the ITO-Ag-Pt contacts had a 17% higher output power (at 20 mA) than the VLEDs fabricated with the ITO-Ag contacts.