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Title: Ultrafast Mid-Infrared Intra-Excitonic Response of Individualized Single-Walled Carbon Nanotubes

Abstract

The quasi-1D confinement and reduced screening of photoexcited charges in single-walled carbon nanotubes (SWNTs) entails strongly-enhanced Coulomb interactions and exciton binding energies. Such amplified electron-hole (e-h) correlations have important implications for both fundamental physics and optoelectronic applications of nanotubes. The availability of"individualized" SWNT ensembles with bright and structured luminescence has rendered specific tube chiralities experimentally accessible. In these samples, evidence for excitonic behavior was found in absorption-luminescence maps, two-photon excited luminescence, or ultrafast carrier dynamics. Here, we report ultrafast mid-infrared (mid-IR) studies of individualized SWNTs, evidencing strong photoinduced absorption around 200 meV in semiconducting tubes of (6,5) and (7,5) chiralities. This manifests the observation of quasi-1D intra-excitonic transitions between different relative-momentum states, in agreement with the binding energy and calculated oscillator strength. Our measurements further reveal a saturation of the photoinduced absorption with increasing phase-space filling of the correlated e-h pairs. The transient mid-IR response represents a new tool, unhindered by restrictions of momentum or interband dipole moment, to investigate the density and dynamics of SWNT excitons.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
Materials Sciences Division
OSTI Identifier:
1001073
Report Number(s):
LBNL-2135E
TRN: US1100267
DOE Contract Number:  
DE-AC02-05CH11231
Resource Type:
Journal Article
Journal Name:
Nature Physics
Additional Journal Information:
Journal Name: Nature Physics
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABSORPTION; AVAILABILITY; BINDING ENERGY; CARBON; CONFINEMENT; DIPOLE MOMENTS; EXCITONS; LUMINESCENCE; NANOTUBES; OSCILLATOR STRENGTHS; PHASE SPACE; PHYSICS; SATURATION; TRANSIENTS; carbon nanotubes, ultrafast dynamics, infrared spectroscopy

Citation Formats

Wang, Jigang, Graham, Matt W, Ma, Yingzhong, Fleming, Graham R, and Kaindl, Robert A. Ultrafast Mid-Infrared Intra-Excitonic Response of Individualized Single-Walled Carbon Nanotubes. United States: N. p., 2009. Web. doi:10.1557/PROC-1230-MM02-04.
Wang, Jigang, Graham, Matt W, Ma, Yingzhong, Fleming, Graham R, & Kaindl, Robert A. Ultrafast Mid-Infrared Intra-Excitonic Response of Individualized Single-Walled Carbon Nanotubes. United States. doi:10.1557/PROC-1230-MM02-04.
Wang, Jigang, Graham, Matt W, Ma, Yingzhong, Fleming, Graham R, and Kaindl, Robert A. Mon . "Ultrafast Mid-Infrared Intra-Excitonic Response of Individualized Single-Walled Carbon Nanotubes". United States. doi:10.1557/PROC-1230-MM02-04. https://www.osti.gov/servlets/purl/1001073.
@article{osti_1001073,
title = {Ultrafast Mid-Infrared Intra-Excitonic Response of Individualized Single-Walled Carbon Nanotubes},
author = {Wang, Jigang and Graham, Matt W and Ma, Yingzhong and Fleming, Graham R and Kaindl, Robert A},
abstractNote = {The quasi-1D confinement and reduced screening of photoexcited charges in single-walled carbon nanotubes (SWNTs) entails strongly-enhanced Coulomb interactions and exciton binding energies. Such amplified electron-hole (e-h) correlations have important implications for both fundamental physics and optoelectronic applications of nanotubes. The availability of"individualized" SWNT ensembles with bright and structured luminescence has rendered specific tube chiralities experimentally accessible. In these samples, evidence for excitonic behavior was found in absorption-luminescence maps, two-photon excited luminescence, or ultrafast carrier dynamics. Here, we report ultrafast mid-infrared (mid-IR) studies of individualized SWNTs, evidencing strong photoinduced absorption around 200 meV in semiconducting tubes of (6,5) and (7,5) chiralities. This manifests the observation of quasi-1D intra-excitonic transitions between different relative-momentum states, in agreement with the binding energy and calculated oscillator strength. Our measurements further reveal a saturation of the photoinduced absorption with increasing phase-space filling of the correlated e-h pairs. The transient mid-IR response represents a new tool, unhindered by restrictions of momentum or interband dipole moment, to investigate the density and dynamics of SWNT excitons.},
doi = {10.1557/PROC-1230-MM02-04},
journal = {Nature Physics},
number = ,
volume = ,
place = {United States},
year = {2009},
month = {6}
}