Optical spectra of (1-101) InGaN/GaN and GaN/AlGaN MQW structure grown on a 7 degree off axis (001) Si substrate

InGaN/GaN and GaN/AlGaN MQW waveguides were fabricated on a (1-101) GaN facet grown on a 7-degree off oriented (001) Si substrates by MOVPE. We achieved uniform layers with less dislocation density and superior flatness by virtue of the low growth rate on the facet. Using a nitrogen laser as the excitation source, the optical gain spectra as a waveguide was evaluated. In the InGaN/GaN MQW structure, we found that the optical gain was as high as +40cm(-1) at near band edge emission peak. The GaN edge emission peak showed narrowing by high intensity excitation: the full width at half-maximum 1.8 nm at under 4.5 MW/cm(2) at 77 K. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.