Controlled synthesis and size-dependent polarization domain structure of colloidal germanium telluride nanocrystals

Publication Type:

Journal Article

Authors:

M.J. Polking; H. Zheng; Ramamoorthy Ramesh; A.P. Alivisatos

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

Abstract:

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.

Notes:

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