Gallium nitride (GaN) nanocrystals have been grown on the tip of aligned carbon nanotubes (CNTs) substrate by chemical vapour transport method. It was found that GaN nanocrystals were formed on the tip and outermost shells of CNT bundles in the form of nanorods. X-ray diffraction (XRD) pattern shows that the GaN nanocrystals are of wurtzite structure. Scanning electron microscopy (SEM) images show the nanocrystals ranging from 10 to 100nm has been realized under different experimental conditions exhibiting different shapes. Heterojunctions between CNTs and GaN nanocrystals, depending on their unique property, can be utilized for nanosized optical and optoelectronic devices. UNT-optical absorption spectrum show the band edge at 360nm, which is related to the bandgap energy of GaN. (C) 2008 Elsevier B.V. All rights reserved.