Long-Lived Dilute Photocarriers in Individualy-suspendedSingle-Walled Carbon Nanotubes
Y. Hashimoto, A. Srivastava, J. Shaver, G. N. Ostojic, S. Zaric, V. C. Moore, R. H. Hauge, R. E. Smalley, and J. Kono
Rice University
Out line•Introduction & Purpose•Sample and Experimental setup•Results and discussion
•Photo-induced carrier dynamics•Polarization memory
•Summary
Longer than 1 nano-second !!!
Supported by TATP and Welch Foundation
ultimate quantum wire
Introduction to Single-Walled Carbon Nanotube
Diameter: 1 nano-meterLength: < 1 inch
Each peakpeak corresponds to particular ((nn,,mm))
Single Walled Carbon Nanotubesphoto-induced carrier life time
Hertel and Moos, Phys. Rev. Lett. 84, 5002 (2000)Chen et al., Appl. Phys. Lett. 81, 975 (2002)Han et al., Appl. Phys. Lett. 82, 1458 (2003)Lauret et al., Phys. Rev. Lett. 90, 057404 (2003)Korovyanko et al. Phys. Rev. Lett. 92, 017403 (2004)
< 1 ps Bundled SWNT
5 - 50 ps Isolated SWNT
G. N. Ostojic et al., Phys. Rev. Lett. 92, 117402 (2004)Y.-Z. Ma et al., J. Chem. Phys. 120, 3368 (2004)A. Hagen et al., Appl. Phys. A 78, 1137 (2004)F. Wang et al., Phys. Rev. Lett. 92, 177401 (2004)
~ 20 ns Theoretical C. D. Spataru et al., cond-mat/0301220 v1 (2003)
~ ns Isolated SWNT This work
PurposePhoto-induced carrier relaxation dynamics
in the low excitation limit
The relaxation dynamics of the photo-excited carriers in SWNTs
radiative Non-radiative
radnonrad
111radradnon
radnon
~ ps ~ ns
Exciton-exciton interaction ?
What kind of the Non-radiative relaxation is taken place ?
~1mJ/cm2~640 e-h pairs
in 1 m SWNT
nmrs 5.1PRL. 92, 077402 (2004)
nmrex 5.2In the previous study with a high-peak power OPA laser
< 20 ps
1 e-h pair per 1 m SWNT
Absorption shows sharp peaks
SWNT is well isolated
Single Walled Carbon Nanotube Sample
Absorption spectrum
2.2
2.0
1.8
1.6
1.4
1.2Ab
sorp
tion
[cm
-1]
1.81.61.41.2
Photon energy [eV]
SWNT
SDS micelle
SDS miscelled SWNT
Science VOL 297 593 (2002)
Experimental setup
/ 2
Pulse picker80 MHz – 800 kHz
Ti:s laser80MHz
Excitation fluence: 100 nJ/cm2
Pump : Probe = 10 : 1
Si detector
Lock in
2.42.0
1.6
1.2
Abs
orpt
ion
[cm
-1]
1.81.71.61.51.4
Photon Energy [eV]
Laser wavelength: 1.550 eV (E2H2)
Delay stage (2 ns) ApertureSWNT
Photo-induced carrier dynamics in SWNTin low excitation limit
Pump and probe signal persist even at 1 nano-second
Photo-induced carrier dynamics shows very long decay !!!
10-6
10-5
10-4
10-3
T/T
8004000Time delay [ps]
Room temperature
Repetition rate: 8 MHz
Polarization of the pump and probe:
Previous report in high excitation
~ 20 ps
1.0x10-3
0.8
0.6
0.4
0.2
0.0
T/T
10005000Time delay [ps]
1: < 1 ps
2: ~ 1 ns
Decay dynamics
E
E1DOS
E2
H2
H1
Decay dynamics
~ ns
E2H2 E1H1 intraband transition
5x10-3
4
3
2
1
0
T/T
10-1Time delay [ps]
E1H1 carrier recombination1.0x10
-3
0.8
0.6
0.4
0.2
0.0
T/T
10005000Time delay [ps]
< 1 ps
1.0
0.8
0.6
0.4
0.2
0.0P
10008006004002000Time delay [ps]
Polarization memory
TTTT
Pll
ll
Polarization memory persist even at 1 ns !!!
10-5
10-4
10-3
T/T
8004000Time delay [ps]
Parallel Perpendicular
In bundled SWNT, the polarization decay time ~ 10 psO. J. Korovyanko et al., Phys. Rev. Lett. 92 017403 (2004)
TTTT
Pll
ll
Polarization of the pump and probe pulses
Summary
•The transient absorption of the isolated SWNTs in low excitation regime shows very fast (< 1 ps) E2H2 E1H1 intraband transition and very long (~ 1ns) E1H1 carrier recombination
Future workTwo color pump-probe in the isolated SWNT
in the low excitation limit
10-6
10-5
10-4
10-3
T/T
8004000Time delay [ps]
•The polarization memory in isolated SWNTs shows no decay even at 1 ns.
1.0
0.8
0.6
0.4
0.2
0.0
P10008006004002000
Time delay [ps]
Excited SWNT(12,1)L : 797 nm(11,3)L : 792 nm(10,5)l : 786 nm(9,7)l : 790 nm
Inte
nsi
ty
150010005000
Raman shift [cm-1
]
RBM mode ~30meVDepend on the diameter of the CNT
G mode ~200meVCaused by the graphite structureDepend on the chirality
Raman spectrum
How to estimate the carrier concentration
Density of the SWNT in solution: ~20 x 10-6g/cm3
Mass density of SWNT (11. 0): 2.06 x 10-18 g/m
Density of the SWNT: 9.7 x 1011m/cm
(in the 1mm path length cuvette)
Excitation intensity: 1 mJ/cm2
Photon energy: 1 eV
Excitation intensity: 6.2 x 1015 photon/cm2
mphotoncmm
cmphoton
/104.6/107.9
%10/102.6 2211
215
Absorption: 10% (per 1 mm)
Long-Lived Dilute Photocarriers in Individualy-suspendedSingle-Walled Carbon Nanotubes
Y. Hashimoto, A. Srivastava, J. Shaver, G. N. Ostojic, S. Zaric, V. C. Moore, R. H. Hauge, R. E. Smalley, and J. Kono
Rice University
Out line•Introduction & Purpose•Sample and Experimental setup•Results and discussion
•Photo-induced carrier dynamics•Polarization memory
•Summary
Longer than 1 nano-second !!!
Supported by TATP and Welch Foundation
ultimate quantum wire
Introduction to Single-Walled Carbon Nanotube
Diameter: 1 nano-meterLength: < 1 inch
Single Walled Carbon Nanotubesphoto-induced carrier life time
Hertel and Moos, Phys. Rev. Lett. 84, 5002 (2000)Chen et al., Appl. Phys. Lett. 81, 975 (2002)Han et al., Appl. Phys. Lett. 82, 1458 (2003)Lauret et al., Phys. Rev. Lett. 90, 057404 (2003)Korovyanko et al. Phys. Rev. Lett. 92, 017403 (2004)
< 1 ps Bundled SWNT
5 - 50 ps Isolated SWNT
G. N. Ostojic et al., Phys. Rev. Lett. 92, 117402 (2004)Y.-Z. Ma et al., J. Chem. Phys. 120, 3368 (2004)A. Hagen et al., Appl. Phys. A 78, 1137 (2004)F. Wang et al., Phys. Rev. Lett. 92, 177401 (2004)
~ 20 ns Theoretical C. D. Spataru et al., cond-mat/0301220 v1 (2003)
~ ns Isolated SWNT This work
PurposePhoto-induced carrier relaxation dynamics
in the low excitation limit
The relaxation dynamics of the photo-excited carriers in SWNTs
radiative Non-radiative
radnonrad
111radradnon
radnon
~ ps ~ ns
Exciton-exciton interaction ?
What kind of the Non-radiative relaxation is taken place ?
~1mJ/cm2~640 e-h pairs
in 1 m SWNT
nmrs 5.1PRL. 92, 077402 (2004)
nmrex 5.2In the previous study with a high-peak power OPA laser
< 20 ps
1 e-h pair per 1 m SWNT
Absorption shows sharp peaks
SWNT is well isolated
Single Walled Carbon Nanotube Sample
Absorption spectrum
2.2
2.0
1.8
1.6
1.4
1.2Ab
sorp
tion
[cm
-1]
1.81.61.41.2
Photon energy [eV]
SWNT
SDS micelle
SDS miscelled SWNT
Science VOL 297 593 (2002)
Experimental setup
/ 2
Pulse picker80 MHz – 800 kHz
Ti:s laser80MHz
Excitation fluence: 100 nJ/cm2
Pump : Probe = 10 : 1
Si detector
Lock in
2.42.0
1.6
1.2
Abs
orpt
ion
[cm
-1]
1.81.71.61.51.4
Photon Energy [eV]
Laser wavelength: 1.550 eV (E2H2)
Delay stage (2 ns) ApertureSWNT
Photo-induced carrier dynamics in SWNTin low excitation limit
Pump and probe signal persist even at 1 nano-second
Photo-induced carrier dynamics shows very long decay !!!
10-6
10-5
10-4
10-3
T/T
8004000Time delay [ps]
Room temperature
Repetition rate: 8 MHz
Polarization of the pump and probe:
Previous report in high excitation
~ 20 ps
1.0x10-3
0.8
0.6
0.4
0.2
0.0
T/T
10005000Time delay [ps]
1: < 1 ps
2: ~ 1 ns
Decay dynamics
E
E1DOS
E2
H2
H1
Decay dynamics
~ ns
E2H2 E1H1 intraband transition
5x10-3
4
3
2
1
0
T/T
10-1Time delay [ps]
E1H1 carrier recombination1.0x10
-3
0.8
0.6
0.4
0.2
0.0
T/T
10005000Time delay [ps]
< 1 ps
1.0
0.8
0.6
0.4
0.2
0.0P
10008006004002000Time delay [ps]
Polarization memory
TTTT
Pll
ll
Polarization memory persist even at 1 ns !!!
10-5
10-4
10-3
T/T
8004000Time delay [ps]
Parallel Perpendicular
In bundled SWNT, the polarization decay time ~ 10 psO. J. Korovyanko et al., Phys. Rev. Lett. 92 017403 (2004)
TTTT
Pll
ll
Polarization of the pump and probe pulses
Summary
•The transient absorption of the isolated SWNTs in low excitation regime shows very fast (< 1 ps) E2H2 E1H1 intraband transition and very long (~ 1ns) E1H1 carrier recombination
Future workTwo color pump-probe in the isolated SWNT
in the low excitation limit
10-6
10-5
10-4
10-3
T/T
8004000Time delay [ps]
•The polarization memory in isolated SWNTs shows no decay even at 1 ns.
1.0
0.8
0.6
0.4
0.2
0.0
P10008006004002000
Time delay [ps]