WP6 : metrology of the metal/semiconductor ratio (MSR) Goal : developing a routine method to measure...
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Transcript of WP6 : metrology of the metal/semiconductor ratio (MSR) Goal : developing a routine method to measure...
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WP6 : metrology of the metal/semiconductor ratio (MSR)Goal : developing a routine method to measure the MSR
Optical spectroscopy technique(s) : * optical absorption (OA)* photoluminescence excitation (PLE)* resonant Raman spectroscopy (RR)
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Optical properties : absorption/emission (PL, fluorescence)
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Optical properties : absorption/emission (PL, fluorescence)Optical transitionsinvolve excitonic states!
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Electronic and optical properties(from Jorio et al)Kataura plot
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Electronic and optical properties(from Jorio et al)Kataura plot!! The Eii vary depending on the environment :individual/bundles, gas/liquid matrix, surfactant/substrate !!
- Arc electric sample (1.2 nm
- Arc electric sample (1.2 nm
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M.J. OConnell et al., Science 297 (2002) 593UnbundlingSynthesis of individual SWNTsJ. Kong et al., Nature 395 (1998) 878Optical properties : emission (PL, fluorescence)Only observed on individual semiconducting SWNT(no contacts with metallic)Excitation (661 nm)Emission(850 nm)
- Bachilo et al, Science, 298, 2361 (2002)Optical properties : NIR fluorescenceIdentification of a (n,m) nanotubefrom the couple (Eii,E11)HiPCO sample (0.7 nm
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*Optical properties : Raman scattering
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*Optical properties : resonant Raman scattering
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Profil mtalliquePics assymtriques, couplages lectrons-phonons2.41 eV1.92 eVProfil semiconducteurPics symtriques, lorentziensResonant Raman scatteringE=2.41 eV(l=514.5 nm)E=1.92 eV(l=647.1 nm)
- Resonant Raman scatteringArc electric sample(1.2 nm
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WP6 : metrology of the metal/semiconductor ratio (MSR)Goal : developing a routine method to measure the MSROptical spectroscopy technique(s) : absorption, PLE, RR
Method 1 : optical absorption in surfactant-based dispersionnarrowing of the spectroscopic signaturesavoids texture-induced effectsone has to know the OA coefficientsAlternative : measurements on transparent quartz substrates
Method 2 : RR spectroscopy (any substrate)very high sensitivity and selectivityone has to mesure the Eii and select a couple of Elaserone has to measure the RR cross sections (coupling with method 1)Alternatives : relative (semi-quantitative) measurements
Couplings with PLE and TEM will help!
Liaisons fortes : combinaison linaire dorbitales atomiques.La fonction donde de l dans le cristal est calcule comme la combinaison linaire des fonctions donde de chaque atome soumisau potentiel dintercation du cristal.Liaisons fortes : combinaison linaire dorbitales atomiques.La fonction donde de l dans le cristal est calcule comme la combinaison linaire des fonctions donde de chaque atome soumisau potentiel dintercation du cristal.