Electron beam stimulated formation of CdS nanoparticles within calixarene Langmuir-Blodgett films

Two possible types of cadmium sulphide (CdS) nanostructures can be formed w ithin Langmuir-Blodgett (LB) films of calixarene Cd salt as a result of exp osure to H2S gas: nanoclusters with the size of about 1.5 nm or two-dimensi onal planes with the thickness of about 1.7 nm. Transmission electron micro scopy and electron diffraction studies on calixarene/CdS LB films show that CdS particles are not present in the fresh samples at the beginning, but t hey are gradually formed under exposure to a high energy electron beam. A b lueshift of the first exciton absorption band and an increase of the extinc tion coefficient, caused by exposure to H2S gas, were found with UV-visible optical spectroscopy and surface plasmon resonance, respectively. (C) 2000 American Institute of Physics. [S0021- 8979(00)07015-8].