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Physics of light-to-electric-signal Physics of light-to-electric-signal conversion in carbon nanotubes conversion in carbon nanotubes
PIs: Slava V. RotkinPIs: Slava V. Rotkin**, Ivan Biaggio, Ivan Biaggio**, , Alma E. WickendenAlma E. Wickenden##
Other team members: Stacy E. SnyderOther team members: Stacy E. Snyder* * (graduate), Happiness (graduate), Happiness MunedzimweMunedzimwe* * (undergraduate), Philip LaPorta(undergraduate), Philip LaPorta* * (graduate), (graduate), Tetyana IgnatovaTetyana Ignatova* * (graduate), (graduate), Lolita RotkinaLolita Rotkina**(research scientist), (research scientist), Vadim PullerVadim Puller++ (postdoc), Igor Kolobov (postdoc), Igor Kolobov++(postdoc)(postdoc)
NanophotonicsNanophotonics DOD-ARL:COT Seed projectDOD-ARL:COT Seed project
## Army Research Lab Army Research Lab* Lehigh University,* Lehigh University,++ at new job place at new job place
General Information General Information SlideSlide
• Non-linear Optics lab (Prof. I. Biaggio)Non-linear Optics lab (Prof. I. Biaggio)
Overview of available methods
• Low-noise low-current (pA) photoelectric Low-noise low-current (pA) photoelectric measurements andmeasurements and
• Theoretical Quantum Physics lab Theoretical Quantum Physics lab (Prof. S.V. Rotkin)(Prof. S.V. Rotkin)
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Nonlinear Optical spectroscopyDegenerate four-wave mixingThree pulses interact to generate a fourth one:
Nanotube solutions:Spectroscopy of two-photon absorptionDetermination of excited state lifetimes
Contacted nanotube samples:Additional information on photocarrier generation from direct electrical measurements in pulsed photocurrent spectroscopy
Allowed and forbidden transitions in NTssemiconductor metal
Photoresponse of Polymer-NT FET
20 40 60 80 100 120 1401
1.005
1.01
1.015
1.02
1.025
1.03
t, sec
Id/Vd / (Idmax/Vd
max)
sample 3sample 6
• Id/Vd curves show that charging of the trap states is equivalent to additional gating of the channel of the NT Field-Effect Transistor (controlled by light absorption)• Kinetics of ion diffusion in the ionomeric polymer is likely to determine the trap discharge
Ionomer-NT interface (SEM image)
500 nm500 nm
200 nm200 nm
Happiness Munedzimwe,
Lehigh Undergraduate
DNA-NT wraps: New Optic Material
Physics graduate student Stacy SnyderPhysics graduate student Stacy Snyder
Theory predicts:- Polarization-resolved olarization-resolved spectroscopy can detect a spectroscopy can detect a helical warp of DNA-NT.helical warp of DNA-NT.- Qualitative changes in - Qualitative changes in the absorption due to the the absorption due to the symmetry breaking plus symmetry breaking plus circular dichroism, absent circular dichroism, absent for the pristine nanotubes. for the pristine nanotubes.
Unperturbed SWNT
ssDNA-Wrapped SWNT: right CP
ssDNA-Wrapped SWNT: left CP
[7,0] SWNT- ssDNA wrap
Eg= E11=1.43 eVEg
pert = 1.33 eV
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Luminescence, eV
Abs
orpt
ion,
eV