Growth temperature dependence of In-rich InGaN growth properties for each Ga/(Ga +In) supply ratio by radio-frequency plasma assisted molecular beam epitaxy was investigated. The luminescence property of In-rich InGaN films up to 20% of Ga improved compared with that of InN because their growth temperatures could be set at high and high purity InGaN films were obtained. This effect can be partly interpreted as a result of the larger bond strength of Ga-N than that of In-N. However, the InGaN films tend to be Ga-rich in case of relatively high growth temperatures. Also, InGaN dot-like structures at intermediate composition were grown as a result of the combination effect of phase separation due to the immiscibility of GaN into InN and local strain due to lattice mismatch between InGaN and underlying GaN buffer layer. (c) 2006 Elsevier B.V. All rights reserved.