Growth of GaN/AlGaN heterostructure and quantum well (QW) on the (1 (1) over bar 0 1) side facets of truncated triangular GaN which is grown on a (1 1 1) silicon substrate is demonstrated for the first time. The cathode luminescence image showed that the composition of AlGaN is not uniform on the side facets, but the photoluminescence spectra exhibited clear peaks, which were attributed to the GaN QW embedded between AlGaN cladding layers. (C) 2002 Elsevier Science B.V. All rights reserved.