Highly efficient group-III nitride based light emitting diodes via fabrication of structures on an N-face surface

US7704763B2 · kind B2 · utility

Assignees

• The Regents of the University of California · US
• Japan Science and Technology Agency · JP

Inventors

• Tetsuo Fujii · Toyohashi, JP
• Yan Gao · Durham, US
• Evelyn L. Hu · Cambridge, US
• Shuji Nakamura · Goleta, US

Key dates

• Filing date: Dec 9, 2003
• Grant date: Apr 27, 2010
• Expiry date: Feb 8, 2024

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10H20/853

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.