Controlled production and electronic characterization of defects in carbon nanotubes

Controlled production and electrical characterization of defects in carbon nanotubesBrett GoldsmithCollins GroupDepartment of Physics and Astronomy

Production of Defects (functionalization)Electrochemical defect creationI(V) of nanotubes with an added defectField sensitivity of a created defectLocal resistance of a created defectEnhancement of Chemical reactivity

2point functionalization = defect (say twice)DiazoniumFluorinationOzone etchingAcid etchingElectrochemical etching

1. Electrochemical Setup electrochemistry in acidic solution monitor current through the nanotube during electrochemistry

PMMAPMMASourceDrainMannik et al. PRL (2006) Goldsmith el al. Science (2007)

3Platinum counter and reference

explain e-chem cell in detail

what is happening during oxidation?

I vs time

2. I(V) of Created Defects

created defects show tunneling behavior

4low bias regionTunneling?

5temperature dependence of tunneling, barrier height Thermally Assisted Tunneling

Mannik et al. PRL (2006)

6tunnel in, thermally excite out

describe electrons going through the defect, 3. Localized Field Sensitivity - SGMRecord current through the nanotube circuit while scanning with a gate probe.Measures local field sensitivityShows where the device is gate sensitive

SourceVSDVtipDrainVFa normal nanotubenanotube with a created defect

4. Local Resistance - KFMRecords forces between tip and sampleMeasures Surface PotentialAllows indirect measurement of local resistance

SourceVSDVtipDrainVF

DrainSourceKFM image of a normal nanotubeA nanotube with a created defectScanned Gate imageKFM image

5. Chemical reactivity of Produced Defects

PMMAPMMAPdGoldsmith el al. Science (2007)

Summary

Dr. Phil Collins

Brett GoldsmithAlex KaneBucky KhalapSteve HuntDanny WanACS-PRFElectrochemical functionalizationThermally assisted tunnelingField sensitivity of created defectLocal resistance of created defectChemical reactivity of created defects