Highly efficient group-III nitride based light emitting diodes via fabrication of structures on an N-face surface
AssigneesThe Regents of the University of California, Japan Science and Technology Agency
InventorsTetsuo Fujii, Yan Gao, Evelyn L. Hu, Shuji Nakamura
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Abstract
A gallium nitride (GaN) based light emitting diode (LED), wherein light is extracted through a nitrogen face (N-face) (42) of the LED and a surface of the N-face (42) is roughened into one or more hexagonal shaped cones. The roughened surface reduces light reflections occurring repeatedly inside the LED, and thus extracts more light out of the LED. The surface of the N-face (42) is roughened by an anisotropic etching, which may comprise a dry etching or a photo-enhanced chemical (PEC) etching.
Claims14
A method of creating a (B, Al, Ga, In)N light emitting diode (LED), comprising:
- fabricating at least an n-type layer, an emitting layer and a p-type layer of the (B, Al, Ga, In)N LED on a substrate;
- exposing a nitrogen face (N-face) surface of the n-type layer by removing the substrate from the layers;
- and
- etching the N-face surface of the n-type layer after the substrate is removed to create a plurality of cones having a size not smaller than 200 nm to increase extraction efficiency of light from the emitting layer out of the N-face surface as compared to the N-face surface without the cones.
Dependencies are inferred from the claim text.