Indium-incorporation efficiency in semipolar (11(2)over-bar2) oriented ingan-based light emitting diodes

Abstract

Reduced electric field in semipolar (11 (2) over bar2) GaN/InGaN heterostructures makes this orientation attractive for high efficiency light emitting diodes. In this work, we investigated indium incorporation in semipolar (11 (2) over bar2) GaN grown by metal-organic chemical vapor deposition on planar m-plane sapphire substrates. Indium content in the semipolar material was compared with that in polar c-plane samples grown under the same conditions simultaneously side by side on the same holder. The investigated samples incorporated dual GaN/InGaN/GaN double heterostructures with 3nm wide wells. In order to improve optical quality, both polar and semipolar templates were grown using an in-situ epitaxial lateral overgrowth (ELO) technique. Indium incorporation efficiency was derived from the comparison of PL spectra measured on the semipolar and polar structures at the highest excitation density, which allowed us to minimize the effect of quantum confined Stark effect on the emission wavelength. Our data suggests increased indium content in the semipolar material by up to 3.0%, from 15% In in cGaN to 18% In in (1122) GaN.