Pii: S0040-6090(99)00661-6

Langmuir±Blodgett (LB) multilayers of arachidic acid (AA) and octadecylamine (ODA) were used as templates in order to produce cadmium sul®de (CdS) nanoparticle arrays. Both atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) were used to characterize the ®lm. In the absence of ODA, the cadmium arachidate trilayers were highly crystalline with a lattice constant of 0.42 nm. Upon reaction with hydrogen sul®de (H2S), an ordered array of CdS nanoparticles with a particle separation of 4.2 nm was imaged. The existence of CdS was also con®rmed by XPS. No CdS nanoparticles were formed when ODA was used as the sole component. In the presence of ODA, the crystalline structure of the AA ®lm was disturbed, resulted in randomly distributed particles. The average particle height was reduced from 4 to 1 nm when the amount of ODA was increased. It is concluded that there is a direct correlation between the ordering of the organic template and that of the nanoparticle array. There is also a correlation between the particle size and the ratio of AA and ODA. Mixed LB ®lms are promising in synthesizing semiconducting nanoparticle arrays of limited particle sizes. q 2000 Elsevier Science S.A. All rights