Hi Everyone,
This Monday, Dr. Normand Modine from Sandia National Labs will be
visiting. He is giving a talk which includes lunch and is summarized
below.
Computing Semiconductor Defect Properties: Band Gap Levels and Beyond
Dr. Normand A. Modine
Sandia National Laboratories
Date: Monday, December 3, 2012
Time: 12:00 noon
Where: LISE 303
What else: lunch provided for those who RSVP
RSVP: send a note indicating plan to attend to stopa(a)cns.fas.harvard.edu
abstract
Calculations based on the Kohn-Sham Density Functional Theory (DFT)
have been widely used to predict the band-gap levels of point defects
in semiconductors. Several additional defect properties are needed in
order to fully understand how defects influence the behavior of
materials. We will discuss a set of ongoing efforts to predict defect
properties using a general approach in which DFT at the atomistic
scale is coupled with other models in order to bridge to longer length
and time scales. For example, DFT results interpreted in light of a
set of approximate bounds on the defect levels are combined with
Franck-Condon theory in order to obtain activation energies for
carrier-capture at defects. Likewise, kinetic Monte-Carlo simulations
based on energies obtained from a cluster expansion fit to DFT results
help us predict the effects of alloying on defect diffusion. Finally,
rate equations and kinetic Monte-Carlo incorporating parameters
obtained from DFT are used to investigate the effects of
non-equilibrium carrier concentrations on defect diffusion and defect
induced carrier recombination. The results of these calculations help
us understand technologically important phenomena in solid-state
lighting and the annealing of radiation damage.
--
Ryan Babbush | PhD Student in Chemistry
(949) 331-3943 | babbush(a)fas.harvard.edu
Harvard University | Aspuru-Guzik Research Group
12 Oxford Street, Box 400 | Cambridge, MA 02138
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