A Comparison of Pressure-Induced Structural Transformations in CdSe, InP, and Si Nanocrystals
Pressure-induced phase transitions in CdSe, InP and Si nanocrystals of 2 to 50 nm in diameter were studied with high pressure X-ray diffraction and optical absorption measurements. All samples were found to transform via a single nucleation event. In addition, all samples transformed at an elevated pressure with a large hysteresis compared to that of the bulk. These phenomena are explained by an overall change in shape of the crystallite after it goes through the phase transition. Evidence for this shape change is shown in the elevation of the phase transition pressure in all samples and in the high pressure shape of the Si nanocrystals. These experiments present an opportunity to investigate first order solid-solid phase transitions on a nanometer scale.
KeywordsRock Salt Transition Path CdSe Nanocrystals Rock Salt Structure Large Hysteresis
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