Fabrication of Mesa Shaped InGaN-Based Light-Emitting Diodes Through a Photoelectrochemical Process

Abstract

InGaN-based light-emitting diodes (LEDs) were fabricated to have a higher light extraction through the photoelectrochemical (PEC) mesa shaping process. After the PEC selective wet oxidation and wet etching processes, stable and controllable crystallographic etching planes were formed as p-type GaN {1011} planes and n-type GaN {1010} planes included at an angle of 27 deg. The ever-present cone-shaped structure of a PEC-treated LED has a larger light scattering area and higher light extraction cones on the mesa sidewall, as analyzed by microphotoluminescence and light output power measurement. This cone-shaped-sidewall LED has a higher light output power and a larger divergence angle compared with a conventional LED measured in an LED chip form

A nanorods AlN layer prepared by sputtering at oblique-angle and application as a buffer layer in a GaN-based light emitting diodes

“…It has been shown that high extraction efficiency in GaN-based LEDs can be obtained by several approaches, including chip shaping, surface roughness, patterned sapphire substrate, photonics crystals, flip-chip packaging and conductive omni-directional reflectors, have been extensively studied. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] In general, GaN-based LEDs are grown on the sapphire substrates, because there is no large substrate available for GaN heteroepitaxial growth. The order of the dislocation density was 108-1010cm-2 has been reported.…”