Chemistry Reference
In-Depth Information
Table 3.2.
Typical experimental CVD conditions for the formation of
[Fe
+
3
(Cp
∗
)
2
][TCNE] and V(TCNE)
x
thin films
Mass
T
vap
He flow rate
T
mix
T
sub
P
Precursor
(mg)
(K)
(sccm)
(K)
(K)
(Torr)
Fe
+
3
(Cp
∗
)
2
134
383
33
433
348
0.5
TCNE
105
348
17
V(C
6
H
6
)
94
418
17
448
348
0.5
TCNE
119
348
10
Note:
This table corresponds to Table 1 from de Caro
et al.
, 2000b.
T
vap
,
T
mix
,
T
sub
stand
for temperatures of vaporization, in the mixing zone and of the substrate, respectively, and
P
corresponds to the measured total pressure.
Figure 3.16. SEM image of (a) [Fe
+
3
(Cp
∗
)
2
][TCNE] and (b) V(TCNE)
x
thin films
deposited on KBr pellets. Reprinted with permission from de Caro
et al.
, 2000b.
Copyright (2000) American Chemical Society.
precursors, where the resulting final products differ from the precursors (type I), or
collective assembling via intermolecular interactions, where the final products and
the precursors are identical (type II).
We illustrate the CVDpreparation of thin films with some examples. The selected
materials are ferromagnetic [Fe
+
3
(Cp
∗
)
2
][TCNE] and the solvent-free V(TCNE)
x
phase. [Fe
+
3
(Cp
∗
)
2
][TCNE] is a ferromagnet with
T
C
=
4.8 K (Miller
et al.
, 1988)
and V[TCNE]
x
orders magnetically above 350 K (Manriquez
et al.
, 1991), as
previously discussed in Section 1.5. Table 3.2 summarizes the CVD conditions for
growth of the thin films. V(TCNE)
x
and [Fe
+
3
(Cp
∗
)
2
][TCNE] correspond to type
I and II, respectively.
As shown in Fig. 3.16, the films are polycrystalline formed of micrometre-sized
crystals. Magnetic measurements performed on the [Fe
+
3
(Cp
∗
)
2
][TCNE] films in-
dicate that
T
C
3
.
7 K (de Caro
et al.
, 2000b). When purely organic precursors are
