TY - JOUR
T1 - Raman scattering study of the thermal conversion of bundled carbon nanotubes into graphitic nanoribbons
AU - Kim, Un Jeong
AU - Gutiérrez, Humberto R.
AU - Gupta, Awnish K.
AU - Eklund, Peter C.
PY - 2008/4
Y1 - 2008/4
N2 - Raman scattering is used to study the temperature-driven structural transformations of bundled single-walled carbon nanotubes (SWCNTs) observed in HiPCO and ARC synthesis by electron microscopy, i.e., tube-tube coalescence ∼1300-1400 °C, coalesced tubes to multi-walled tubes (MWCNT) at ∼1600-1800 °C and finally (only ARC tubes) MWCNT to graphitic nanoribbons (GNRs) at ∼1800 °C. All these transformations occurred in vacuum. Here, we present the details of these transformations as seen through the "eyes" of Raman scattering via changes in the radial (R) SWCNT band, the G-band (and its substructure) and the relative intensity of the disorder-induced D- and D′-band scattering. The Raman spectrum of GNRs is also discussed in detail. For 514.5 nm laser excitation, five relatively broad GNR Raman bands are observed: 1350, 1580, 1620, 2702 and 3250 cm-1. A Knight plot is used to estimate the GNR width and we find w ∼ 9 nm, which is in reasonable agreement with the estimate of 7.6 nm based on TEM and the model that a GNR is a collapsed MWCNT.
AB - Raman scattering is used to study the temperature-driven structural transformations of bundled single-walled carbon nanotubes (SWCNTs) observed in HiPCO and ARC synthesis by electron microscopy, i.e., tube-tube coalescence ∼1300-1400 °C, coalesced tubes to multi-walled tubes (MWCNT) at ∼1600-1800 °C and finally (only ARC tubes) MWCNT to graphitic nanoribbons (GNRs) at ∼1800 °C. All these transformations occurred in vacuum. Here, we present the details of these transformations as seen through the "eyes" of Raman scattering via changes in the radial (R) SWCNT band, the G-band (and its substructure) and the relative intensity of the disorder-induced D- and D′-band scattering. The Raman spectrum of GNRs is also discussed in detail. For 514.5 nm laser excitation, five relatively broad GNR Raman bands are observed: 1350, 1580, 1620, 2702 and 3250 cm-1. A Knight plot is used to estimate the GNR width and we find w ∼ 9 nm, which is in reasonable agreement with the estimate of 7.6 nm based on TEM and the model that a GNR is a collapsed MWCNT.
UR - http://www.scopus.com/inward/record.url?scp=41549167592&partnerID=8YFLogxK
U2 - 10.1016/j.carbon.2008.01.030
DO - 10.1016/j.carbon.2008.01.030
M3 - Article
AN - SCOPUS:41549167592
SN - 0008-6223
VL - 46
SP - 729
EP - 740
JO - Carbon
JF - Carbon
IS - 5
ER -