Peculiarities of CdS nanocrystal formation at annealing of a Langmuir-Blodgett matrix

Formation and assembling of CdS nanocrystals (NC) on highly-ordered pyrolytic graphite (HOPG) and on oxidized silicon substrates have been investigated by atomic force microscopy (AFM) and scanning tunneling microscopy (STM). NC were initially formed within a Langmuir-Blodgett (LB) matrix of cadmium behenate. The LB matrix was then removed by annealing in an ammonia atmosphere. It is shown that the NC self-assembling is mainly determined by the LB matrix wetting properties. In case of wettable HOPG substrate homogeneous matrix evaporation occurs that leads to coarsening of the NC arrays as the main self-assembly process. Otherwise, NC prepared on non-wettable SiO2-Si substrate demonstrate arrays formation determined by the LB matrix dewetting process. For the both cases, the influence of kinetic limitations connected with matrix evaporation rate on the self-assembly process is observed. (C) 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim