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

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Id/Vd / (Idmax/Vd

max)

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• 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

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ion,

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