Chemistry Reference
In-Depth Information
Fig. 5.6
Top panel
: velocity vs. time determined from the position of the center of mass of a
moving island.
Bottom panel
: using the measured island size as a function of time, the velocity is
determined as a function of radius. The
black solid line
is a one-parameter fit of the experimental
data to
09 nm
2
v
=
C
/
R
yielding
C
=
1
.
93
±
0
.
/
s
k
B
T
β(θ)
sin
θ)
2
√
3
(
3
=
(5.7)
from 5
◦
to 30
◦
, we obtain the average value for rough step edges
of 0.51 eV/nm at 318 K.
The edge diffusion constant
D
L
is related to the step edge mobility
By averaging
θ
h
as
D
L
=
a
2
//
25 nm. The step edge mobility
is determined by direct measurement of the equilibrium fluctuations of the steps,
quantified by the prefactor
G
0
of the time correlation function via [
41
]
c
st
D
st
=
h
, where
a
//
=
0
.
29 nm and
a
⊥
=
0
.
a
2
⊥
a
//
