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]