Thin films of the chalcopyrite semiconductor CuInSe2 were grown by an ionized cluster beam (ICB) deposition technique at a low substrate temperature of 300 degrees C. We studied the effect of nozzle diameter (a perforation on the top lid of the crucibles) of the cluster-source crucibles on the thin films. The diameters were 1.7, 2.0, or 3.0 mm. The deposited films obtained were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), electron probe microanalysis (EPMA), scanning ion mass spectroscopy (SIMS), and Raman spectroscopy. Change in the nozzle diameter significantly affected both the intensity of the Raman peaks at 183 and 260 cm(-1) and the crystallinity of the CuInSe2 films. The maximum diameter for obtaining good crystallinity of CuInSe2 films is between 2.0 and 3.0 mm. It is found that the energy of Cu clusters plays a very important role in the crystal growth of CuInSe2.