We have synthesized firework-like Co2P nanostructures using a simple and reliable thermal decomposition route with the precursors, triphenyl phosphine and cobalt acetylacetonate, in oleylamine. The optimized reaction temperature is within a narrow window around 280 _C. The nanostructures have a firework-like morphology with nanoneedles growing out of a center core. The nanoneedles are single crystals with clean surfaces, about 200 nm in length, and a tapering tip less than 10 nm in diameter. These nanostructures exhibit Curie–Weiss PM behavior with the effective moment determined as 2.46 mB per FU. Based on the synthesis designs with detailed characterizations on the intermediates at different stages of the phase formation, the growth mechanism of the firework-like Co2P nanostructures is proposed. It is feasible to apply this method of synthesis for some of the other transition-metal phosphide nanostructures.

The structural stability of FePt nanoparticles of about 5-6nm diameter was investigated by dynamic high resolution transmission electron microscopy. The FePt icosahedra were very stable under an electron beam flux of～20 A/cm2 at 300 kV. Surface sputtering was suppressed due to the large sputtering threshold energy of a Pt-rich shell. Under a flux of～50 A/cm2, the trapping potential well of the FePt particle on the supporting carbon film was lowered by the magnetic interaction between the electron beam and the particle, which leads to rotational and translational motions of the particle. A large dose of electrons (of～200 A/cm2) initiated melting and recrystallization of the FePt particle. The structure of the FePt nanoparticle, a Pt enriched shell around an Fe/Pt magnetic core, is believed to be responsible for its dynamic behaviour under different beam conditions.

Ultrathin ZnS nanobelts were assembled by ultrasmall nanocrystals with oriented self assembly, which were then transformed into their single-crystal counterparts by thermal treatment in N2. ZnO/ZnS heterostructures were also obtained at elevated temperature in open air, where well aligned ZnO nanocones were grown along the ZnS nanobelts with a definite rientation relationship described as 0001 ZnS 0001 ZnO and 101¯0 ZnS 101¯0 ZnO. Mixed transition and tuned band gaps of the heterostructure were experimentally observed, which was in good agreement with the theoretical predications and can be interpreted based on the model of a strained staggered type-II band structure. © 2010 American Institute of Physics.