The Center for Advanced Mathematical Sciences
(CAMS)
invites you to a seminar entitled
"Statistical Model for Thermal Conductivity in Nanostructures:
Application to Si”
By
Michel Kazan
Department of Physics, American University of Beirut
Date
Mon. Jan 31, 2011 at 4:00 P.M.
Location
CAMS, College Hall, Room 416
Abstract
We present an analytical model for the thermal conductivity in nanostructured
materials that takes into account the physical nature of the phonon mechanisms
in semiconductor nanostructures. Following Callaway solution for the Boltzmann
equation, where resistive and nonresistive phonon mechanisms are discriminated,
we derive formalism for the thermal conductivity that accounts for the phonon
incidence angle. The phonon-boundary scattering mechanism, which is supposed to
be the dominant scattering mechanism in the nanostructures, is described by a
rigorous statistical model. The scattering rate of this process is obtained as
a function of the phonon frequency, incidence angle, and the nanostructure
asperities. Another key development we present in our model is that we go
beyond the conventional one phonon approximation and we consider the
regeneration of the scattered acoustic phonon from the decay of the optical
phonon. The importance of all the mechanisms we have involved in the model is
demonstrated clearly with reference to available experimental data regarding
the thermal conductivity of natural and isotopically rich bulk Si, smooth and
rough Si nanowires, and porous Si.