Double-sided pattern design on patterned sapphire substrate of GaN-based LEDs

Abstract

In this paper, we established a optical model and made an analysis of GaN-based LED flip chip by double-sided PSS (patterned sapphire substrate). The result analysis shows that the small distance and large radius of micro-cylinder and micro-hemisphere for cylindrical and hemispherical PSS would be more effective to enhance LED efficacy. The hemispherical pattern is more efficient than the cylindrical for enhancement for the light extraction efficiency (LEE) of PSS-LED flip chip. The light extraction efficiency of micro-hemispherical PSS-LED chip is twice than that on the non-patterned (or normal planar) sapphire substrate (non-PSS).