Study of green light-emitting diodes grown on semipolar (11–22) GaN/m-sapphire with different crystal qualities

We investigated the anisotropic optical and structural properties of semipolar (11–22) InGaN-based green light emitting diodes (LEDs) grown on GaN templates with the different crystallographic properties. By introducing the N2-GaN as a seed layer grown at a N2 atmosphere, the full width at half maximum (FWHMs) of X-ray rocking curves (XRCs) for semipolar GaN templates were decreased from 1331 to 727 arcsec and from 1955 to 1076 arcsec with the incident beam directions of [11–2–3] and [1–100], respectively. It was found that the interfacial qualities of InGaN/GaN quantum wells (QWs) would be improved by reducing the FWHMs of XRCs with regardless of crystallographic directions. However, the thickness uniformity of InGaN QWs was significantly deteriorated for the direction of [11–2–3] rather than [1–100]. In addition, the EL intensity of semipolar green LEDs would be increased by enhancing the crystal quality of semipolar GaN template, which could also be resulted in the formation of abrupt interface and the enhancement of homogeneity at InGaN/GaN QWs.