Hexagonal Truncated Pyramidal Light Emitting Diodes through Wafer Bonding of ZnO to GaN, Laser Lift-off, and Photo Chemical Etching

Abstract

We report on a hexagonal pyramidal light emitting diodes (LEDs) produced by direct wafer bonding of a metal organic chemical vapor deposition (MOCVD) grown GaN LED on sapphire to a n-type ZnO wafer, laser lift off, and photochemical etching of the nitrogen face of the GaN LED. Laser lift off was used to remove the sapphire of the GaN wafer, exposing the Nitrogen face for roughening, in the form of microcones, as well as allowing deposition of metal contacts to the nitrogen face of the GaN LED. Contacts to the ZnO allow for the creation of a vertical current path. Selective etching was used to form truncated hexagonal pyramids of the ZnO.