In(Ga)N/GaN multiple quantum well structures with high indium composition were grown using pure InN in well layers by low-pressure metalorganic chemical vapor deposition. Blue emission using a thin In(Ga)N well width grown with only trimethylindium as a III-source showed strong carrier localization originating from a large fluctuation in indium composition and a reduced quantum-confined Stark effect due to the use of a thin well, both of which enhanced quantum efficiency. In contrast, an increase in InN growth time to achieve green emission exhibited a large blueshift of electroluminescent emission under forward-bias current and microstructural defect formation, which were responsible for the observed degradation in emission properties. (c) 2007 Elsevier B.V. All rights reserved.