AbstractInN/InGaN multiple quantum well structures have been fabricated on InN templates grown on (0 0 0 1) sapphire substrates by radio‐frequency plasma‐assisted molecular beam epitaxy. The structures were confirmed by X‐ray diffraction, and satellite peaks up to the 3rd order were observed. From InN/InGaN multiple quantum well structures with different well widths, photoluminescence (PL) emission from the well layers was observed at 77 K, and the PL peak energy slightly blueshifted with decreasing the well width. This dependence can be explained by combined effects of quantum size effect, quantum confined Stark effect, and band filling effect. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)