1 / 26

Measure Surface Potential : Two Known KPFM Modes FM Provides high resolution and accuracy

Measure Surface Potential : Two Known KPFM Modes FM Provides high resolution and accuracy. KPFM measures the work function difference of tip/sample. Physical Review B 2005, 71(12) 125424. Bruker Confidential. Adjusting Vdc , until the first harmonic electric force equals to zero.

chmielewski
Download Presentation

Measure Surface Potential : Two Known KPFM Modes FM Provides high resolution and accuracy

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Measure Surface Potential: Two Known KPFM ModesFM Provides high resolution and accuracy KPFM measures the work function difference of tip/sample. Physical Review B 2005, 71(12) 125424 Bruker Confidential

  2. Adjusting Vdc, until the first harmonic electric force equals to zero

  3. The measured electric force is contributed from tip and the body of the cantilever Which decrease the spacial resolution and accuracy.

  4. Adjusting Vdc, until the first harmonic electric force Gradient equals to zero

  5. The measured electric force gradient mostly contributed from tip, NOT the body of the cantilever So the spacial resolution and accuracy is much higher than AM-KPFM.

  6. Scaling Topography and PotentialPeakForce KPFM to Take Us Further • But Tapping Mode Requires : • k to be not too small • Q not to be too big Tapping and KPFM scaling in conflict. • Peak Force Tapping Mode Allows Freedom to use: • Smaller k (10x or more) • Big Q (10x or more) PeakForce Tapping and KPFM scaling aligned. Bruker Nano Surfaces Division

  7. PeakForce KPFM RetainsFM-KPFM’s High Resolution PeakForceKPFM-AM PeakForceKPFM Bruker Nano Surfaces Division

  8. PeakForce KPFM Offers Simultaneous Mechanical Information LDPE Height 100 nm PS Modulus 10 MPa Potential 150 mV Deformation 25 nm PS=PolyStyrene LDPE=Low Density PolyEthylene Adhesion 5 nN Bruker Nano Surfaces Division

  9. Peakforce FM-KPFM has better spacial resolution and accuracy, but when the features is too small, limitation exists.

  10. PF-KPFM for quantitative characterization of work function“Remove the Residual Additives toward Enhanced Efficiency with Higher Reproducibility in Polymer Solar Cells.” PF-KPFM surface potential images (1μm scan) • PF-KPFM shows that the methanol wash (Device C) increased the work function difference • This reduced the electron injection barrier, leading to better device performance Pure polymer Ye, L. et al., 2013. J. Phys. Chem. C, 117(29), pp.14920–8 Bruker Confidential

  11. C-AFM Principle of Operation (1.0 pA – 1.0 mA) extra gain + filter pA-Amplifier conductive AFM probe to ADC DC bias voltage (-12V to +12V) 1 nA / V gain 1 pA RMS noise

  12. TUNA Principle of Operation (50 fA –100 pA) extra gain + filter pA-Amplifier conductive AFM probe to ADC Closed loop (constant current mode) In development thin dielectric film DC bias voltage (-12V to +12V) 1pA / V gain 50 fA RMS noise

  13. Conducting Probe Atomic Force Microscopy: A Characterization Tool for Molecular Electronics ( C.D. Frisbie, Adv. Mater. 1999 11 261)

  14. Resistance of Grain Boundary

  15. Probing Electrical Transport in Nanomaterials: Conductivity of Individual Carbon Nanotubes Science 272 523(1996)

  16. PF-TUNA extends nanoscale electrical characterization with exclusive PeakForce Tapping technology • High bandwidth, high gain, yet low noise: The high 20pA/V gain setting provides at once full peak current detection with >10kHz bandwidth and most sensitive current imaging with <100fA noise in the cycle averaged current. • 6 gain settings from 100nA/V to 20pA/V access <100fA to >100nA current range without changing probe holder or amplifier. Benefit: Remain on the same spot on the sample the whole time. • Complementary correlated information from PF QNM: directly correlated nanomechanical and conductivity properties Bruker Confidential

  17. PeakForce TUNA • PF-TUNA extends nanoscale electrical characterization with exclusive PeakForce Tapping technology • Simultaneously collect conductivity, modulus, adhesion, dissipation, and deformation data at each imaging pixel. • PFTUNA is enabled by a new current amplifier design • 6 selectable gain settings • <100fA to >100nA current range • Peak Current C • Contact-Averaged Current B<-->D • Cycle-Averaged Current (TUNA Current) • A<------>E Bruker Confidential

  18. PeakForce TUNA Application PP+rubber+CB. Top surface vs. Bulk 5 V Top Current, 3V Adhesion Modulus Height 1.19 nA 1.06 nA 720 pA Bulk Height Current, 3V Adhesion Modulus ~0.9 GPa 1.20 nA 522 pA 740 pA ~100 MPa ~75 MPa Bruker Confidential

  19. PeakForce TUNA Application Adhesion Height small and fragile samples, very challenging to contact mode based conductivity measurements P3HT Organic conductive nanowires height~3 nm Peak Current, +3V bias TUNA Current, +3V bias width~15 nm ~15 pA ~100 pA Adhesion Bruker Confidential

  20. PF-TUNA for high-resolution mapping of current on polymer-nanotube composites“Nanoscale investigation of the electrical properties in semiconductor polymer-carbon nanotube hybrid materials.” Topography Current • Topographic imaging can confirm that the CNTs are dispersed and the P3HT fibers grow perpendicular to the CNT • High-res PF-TUNA current map indicates that the current is controlled by the spreading resistance beneath the tip • Negligible lateral forces and normal force ~50pN make it possible to map current distribution over individual nanofibers Carbon nanotube Desbief, S. et al., 2012. Nanoscale, 4(8), pp.2705–12. Bruker Confidential

More Related