Aya Miura

Realization of High-Crystalline-Quality Thick m-Plane GaInN Film on 6H-SiC Substrate by Epitaxial Lateral Overgrowth

A high-crystalline-quality thick m-plane Ga0.92In0.08N film has been realized by epitaxial lateral overgrowth (ELO). The photoluminescence intensity of thick ELO-GaInN is about 6 times stronger than that of conventional thick GaInN. We fabricated a light-emitting diode (LED) having a GaInN/GaN multiquantum wells (MQWs) active layer on an ELO-GaInN layer. Satellite peaks of (1010) in the 2θ/ω-scan X-ray diffraction profile from this LED can be clearly observed, suggesting that MQWs having a sharp interface are grown. This new LED exhibits blue-light emission with a peak wavelength of 450 nm.

Characterization of low-defect-density a-plane and m-plane GaN and fabrication of a-plane and m-plane LEDs

We report on low-defect-density non-polar a-plane and m-plane GaN films grown by sidewall epitaxial lateral overgrowth (SELO) technique. Dislocations and stacking faults were decreased markedly over the whole area, and surface roughness was decreased with decreasing defect density. The photoluminescence intensity of SELO a-plane and m-plane GaN was about 200 times higher than that of a-plane and m-plane GaN template. We also fabricated and characterized LEDs on a-plane and m-plane GaN using SELO technique. The light power of LEDs increased with decreasing of threading dislocation.

Characterization of a-plane AlGaN/GaN heterostructure grown on r-plane sapphire substrate

The anisotropically biaxial strain in a-plane AlGaN on GaN is investigated by X-ray diffraction analysis of the heterostructure of AlGaN and GaN grown on r-plane sapphire. The AlGaN layer with a low AlN molar fraction or small thickness is coherently grown on the GaN layer both along the m-axis and c-axis. An increase in AlN molar fraction or thickness in AlGaN, results in a slight relaxation of AlGaN only in one direction due to tensile stress along the c-axis, which is caused by the underlying GaN layer during the growth. The cause of the relaxation of AlGaN in one direction is thought to be a large anisotropically biaxial stress.