InGaN Light-Emitting Diodes with Embedded Roughened Structure in the GaN/Sapphire Interface Formed Using Laser Decomposition Process

Abstract

InGaN-based light-emitting diodes (LEDs) with inverted pyramidal structures at their GaN/patterned-sapphire interfaces were fabricated by laser decomposition and wet crystallographic etching. Partially roughening the LED structure increased the light output power of the by 21% enhancement at an operating current of 20mA over that of a non-treated LED structure. The transmittance of the roughened LED structure (10.5%) was lower than that of a non-treated LED structure (20.3%) at 447nm because the incident light was mostly reflected and scattered by the patterned-sapphire structure and by the roughened structure at the GaN/sapphire interface. The light emission intensity in the laser-treated striped region, with the roughened N-face GaN surface was higher than that in the non-treated patterned sapphire region. The InGaN structure with the roughened inverted pyramidal structure increased the light extraction efficiency of nitride-based LEDs.