Polymer-Controlled Growth of CdSe Nanoparticles into Micro- and Nanowires

Keywords:
nanoparticles, CdSe, semiconductor wires, block copolymers

Abstract:
This work reports an easy and effective method to prepare CdSe semiconductors nanoparticles stabilised by using amphiphile diblock copolymer polystyrene-block-polyvinylpyridine [PS-b-P4VP] in nonaqueous medium. spin coating on native oxide Si-wafers showed a core-shell structure of CdSe nanoparticles in the core, encased in a shell of the block copolymer. An unexpected structure was formed after specific thermal treatment of CdSe/PS-b-P4VP thin film (spin-cast) on native oxide Si-wafers. CdSe wires in micro- and nanometer scales were produced. The aggregation of CdSe nanoparticles during the thermal elimination of the polymer phase caused the growth of wires. The wires have a diameter between 0.4- 2 ìm depending on the film thickness and length of 250 ìm. SEM was used to observe the mechanism of the wire formation on the Si-wafer substrate. Moreover, electrical conductivity measurements demonstrated that these are semiconducting. It is believed that the thermal treatment of the polymer CdSe complex leads to dewetting the polymer phase, which causes the CdSe nanoparticles to aggregate into wires.

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Nanotech 2005 Conference Program Abstract