Web Release Date: February 22,
Mechanical and Thermal Properties of Metallic and Semiconductive Nanostructures
and
CICECO, University of Aveiro, 3810-193 Aveiro, Portugal, and Physics of Condensed Matter, University of Mons-Hainaut, Avenue Maistriau 23, 7000 Mons, Belgium
Received: September 13, 2007
In Final Form: November 28, 2007
Abstract:
Using a top-down approach, we report a theoretical investigation of the melting temperature at the nanoscale,
Tm, for different shapes of "free-standing" nanostructures. To easily calculate the nanoscale melting temperature
for a wide range of metals and semiconductors, a convenient shape parameter called 
shape is defined.
Considering this parameter, we argue why smaller size effects are observed in high bulk melting temperature
materials. Using Tm, a phase transition stress model is proposed to evaluate the intrinsic strain and stress
during the first steps of solidification. Then, the size effect on the Thornton & Hoffman's criterion at the
nanoscale is discussed and the intrinsic residual stress determination in nanostructures is found to be essential
for sizes below 100 nm. Furthermore, the inverse Hall-Petch effect, for sizes below ~15 nm, can be understood
by this model. Finally, the residual strain in hexagonal zinc oxide nanowires is calculated as a function of the
wire dimensions.
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