We studied the carrier confinement in tetrapod-shaped colloidal CdTe nanocrystals by means of absorption, photoluminescence, and photoluminescence excitation spectroscopy at room and cryogenic temperatures. The spectra show features characteristic of the tetrapod shape together with a clear dependence on the dominant confinement parameter, i.e., the diameter of the tetrapod arm. Theoretical calculations based on an envelope-function approximation and using the exact tetrapod shape have been performed to assign the observed spectral features. Oscillator strength and size dependence of the transitions energy have been calculated showing a direct correlation between the oscillator strength and the nanocrystal shape.

1.
X. G.
Peng
,
L.
Manna
,
W. D.
Yang
,
J.
Wickman
,
E.
Scher
,
A.
Kadavanich
, and
A. P.
Alivisatos
,
Nature (London)
404
,
59
(
2000
).
2.
T.
Mokari
and
U.
Banin
,
Chem. Mater.
15
,
3955
(
2003
);
C.
Pacholski
,
A.
Kornowski
, and
H.
Weller
,
Angew. Chem., Int. Ed.
41
,
1188
(
2002
).
3.
J. T.
Hu
,
L. S.
Li
,
W. D.
Yang
,
L.
Manna
,
L.
Wang
, and
A. P.
Alivisatos
,
Science
292
,
2060
(
2001
).
4.
L.
Manna
,
D. J.
Milliron
,
A.
Meisel
,
A.
Scher
, and
A. P.
Alivisatos
,
Nat. Mater.
2
,
382
(
2003
).
5.
D. J.
Milliron
,
S. M.
Hughes
,
Y.
Cui
,
L.
Manna
,
J.
Li
,
L. W.
Wang
, and
A. P.
Alivisatos
,
Nature (London)
430
,
190
(
2004
);
K. A.
Dick
,
K.
Deppert
,
M. W.
Larsson
,
T.
Martensson
,
W.
Seifert
,
L. R.
Wallenberg
, and
L.
Samuelson
,
Nat. Mater.
3
,
380
(
2004
).
[PubMed]
6.
M.
Nirmal
,
D. J.
Norris
,
M.
Kuno
, and
M. G.
Bawendi
,
Phys. Rev. Lett.
75
3728
(
1995
);
[PubMed]
A. L.
Efros
,
M.
Rosen
,
M.
Kuno
,
M.
Nirmal
,
D. J.
Norris
, and
M.
Bawendi
,
Phys. Rev. B
54
,
4843
(
1996
);
Z. H.
Yu
,
J. B.
Li
,
D. B.
O’Connor
,
L. W.
Wang
, and
P. F.
Barbara
,
J. Phys. Chem. B
107
,
5670
(
2003
).
7.
D. J.
Norris
,
A. L.
Efros
,
M.
Rosen
, and
M.
Bawendi
,
Phys. Rev. B
53
,
16347
(
1996
).
8.

The peak around 2 eV has been attributed to the solvent by performing PLE measurements on the solution in the absence of nanocrystals.

9.

By a rough fit of the ratio between the intensity of the two PL peaks as a function of the temperature and considering one Arrhenius plot we obtain an activation energy which falls within the 10% margin of error of the energy spacing between the two states, as measured from the PL spectra.

10.
J.
Perez-Conde
,
A. K.
Bhattacharjee
,
M.
Chamarro
,
P
Lavallard
,
V. D.
Petrikov
, and
A. A.
Lipoovskii
,
Phys. Rev. B
64
,
113303
(
2001
).
11.
I. Calderon-Hernandez
, edited by
M. C.
Tamargo
(New York,
2001
);
F.
Long
,
W. E.
Hagston
,
P.
Harrison
, and
T.
Stirner
,
J. Appl. Phys.
82
,
3414
(
1997
);
Y.
Yan
,
M. M.
Al-Jassim
,
K. M.
Jones
,
S. H.
Wei
, and
S. B.
Zang
,
Appl. Phys. Lett.
77
,
1461
(
2000
);
S. H.
Wei
and
S. B.
Zhang
,
Phys. Rev. B
62
,
6944
(
2000
).
12.
I.
Visoly-Fisher
,
A.
Sitt
,
M.
Wahab
, and
D.
Cahen
,
ChemPhysChem
6
,
277
(
2005
).
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