Sputter deposition of Sn-doped ZnO/Ag/Sn-doped ZnO transparent contact layer for GaN LED applications

Sn-doped ZnO/Ag/Sn-doped ZnO (ZAZ) multilayers prepared using sputtering process was employed in GaN-based blue light-emitting diodes(LEDs) as transparent contact layers (TCLs). The ZAZ layer had better optical and electrical properties without any thermal annealing. The ZAZ TCLs improved the current spreading on p-GaN layer and increased the light output power in the large area devices. The efficiency droop was also quite small in the case of adopting a ZAZ TCL in GaN-based LEDs. These results are promising for the development of a ZAZ TCL using sputtering process for GaN LED applications.