Publication Type:Journal Article
Source:Journal of the American Chemical Society, Volume 133, Number 7, p.2044-2047 (2011)
Keywords:Amorphous materials, Article, chemical structure, colloid, Controlled synthesis, Crystalline phase transition, Ferroelectric distortion, Ferroelectric materials, Germanium, Germanium telluride, low temperature, Low temperatures, Materials properties, Monodomains, Multiple polarizations, Nano-scale system, nanocrystal, nanocrystals, Non-volatile memory application, particle size, Phase change process, phase transition, phase transitions, Polar phase, Polarization, Polarization domain, Rhombohedral structures, room temperature, synthesis, transmission electron microscopy, unclassified drug
Germanium telluride (GeTe) exhibits interesting materials properties, including a reversible amorphous-to-crystalline phase transition and a room-temperature ferroelectric distortion, and has demonstrated potential for nonvolatile memory applications. Here, a colloidal approach to the synthesis of GeTe nanocrystals over a wide range of sizes is demonstrated. These nanocrystals have size distributions of 10-20% and exist in the rhombohedral structure characteristic of the low-temperature polar phase. The production of nanocrystals of widely varying sizes is facilitated by the use of Ge(II) precursors with different reactivities. A transition from a monodomain state to a state with multiple polarization domains is observed with increasing size, leading to the formation of richly faceted nanostructures. These results provide a starting point for deeper investigation into the size-scaling and fundamental nature of polar-ordering and phase-change processes in nanoscale systems. © 2011 American Chemical Society.
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