Effects of growth interruption on high indium content InGaN/GaN multi quantum wells

The effects of the growth interruption time on the optical and the structural properties have been investigated. The high indium content In_{cursive Greek chi}Ga_{1-cursive Greek chi}N/GaN (cursive Greek chi > 0.25) multi quantum wells used in this study were grown on c-plane sapphire by using metalorganic chemical vapor deposition. The interruption was carried out by closing the group-III metal organic sources before and after the growths of the InGaN quantum well layers. With increasing interruption time, the quantum dot like region and well thickness decreased due to indium re-evaporation or the thermal etching effect. As a result, the PL peak position was blue-shifted, and the intensity was reduced. The sizes and the number of V-defects did not differ with the interruption time. The interruption time was not directly related to the formation of defects. The V-defects originate at threading dislocations and inversion domain boundaries due to higher misfit strain.