Kai Sun

Associate Research Scientist

kaisun@umich.edu

2800 Plymouth Road, NCRC Building 22 G013

T: (734) 936-3353

Bio

Publications

Facilities

Group


Research Facilities

Bruker Dimension Icon Atomic Force Microscope
Location: Room G022, Building 22 of The North Campus Research Complex

Atomic force microscopy (AFM), scanning force microscopy (SFM) is a high-resolution microscopic technique where the microscopic information is gathered by "feeling" the surface with a mechanical probe. Piezoelectric scanners facilitate (in x,y and z directions) tiny, but accurate, movements to enable very precise scanning. With demonstrated resolution on the order of fractions of a nanometer, more than 1000 times better than the optical diffraction limit, AFM has become a standard technique for surface analysis of materials.

Some of these applications may require the purchase of special cantilevers, cantilever holders, etc.

  • Contact AFM
  • Tapping AFM
  • Lateral Force AFM
  • STM (needs a tip holder)
  • Magnetic Force Microscopy
  • Veeco's ScanAsyst / PeakForce Tapping
  • Fluid Imaging
  • Veeco's QNM (nanomechanical mapping)
  • Surface Potential / Scanning Kelvin Probe Microscopy
  • Phase Imaging
  • LiftMode (enables MFM/EFM)
  • Force curve and pulling
  • Torsional Resonance Mode
  • Piezo Response
FEI Nova Nanolab Dualbeam Focussed Ion Beam Workstation and Scanning Electron Microscope
Location: Room G023, Building 22 of The North Campus Research Complex
  • 1.1 nm @ 15 kV (TLD-SE)
  • 2.5 nm @ 1 kV (TLD-SE)
  • 3.5 nm @ 500V (TLD-SE)
FEI Quanta 200 3D Focussed Ion Beam Workstation and Environmental Scanning Electron Microscope
Location: Room G029, Building 22 of The North Campus Research Complex

Environmental Scanning Electron Microscopy: Although an Environmental Scanning Electron Microscope produces a scanned image similar to that of a regular scanning electron microscope, the environment of the sample chamber and the method of detecting the secondary electron signal are novel. The sample chamber is held at a pressure of typically between 1-20 torr.

  • Imaging - Gaseous Environmental Secondary Detector (GSED)
  • Imaging - Everhart-Thornley Detector (SED)
  • Imaging - Environmental BackScatter Detector
  • X-ray - Noran UTW XEDS Detector with 4Pi analysis system (to be installed)
  • 3.5nm @ 30kV at high vacuum
  • 3.5nm @30kV in ESEM mode
  • 15nm @ 3kV in low vacuum mode
JEOL 2010F Analytical Electron Microscope
Location: Room G020, Building 22 of The North Campus Research Complex

Analytical Electron Microscopy is a generic term that is applied to any study where a variety of analysis techniques are used within one particular microscope. These techniques typically include X-ray Energy Dispersive Spectroscopy (XEDS), Electron Energy Loss Spectroscopy (EELS), Selected Area Electron Diffraction (SAED), Convergent Beam Electron Diffraction (CBED), Scanning Transmission Electron Microscopy, and Scanning Electron Microscopy.

  • XEDS, PEELS, EFTEM, SAED, NBED, CBED, HREM, STEM, HAADF, Spectrum image/Image spectrum, Diffraction Contrast Imaging
  • CTEM 0.10 nm lattice / 0.25 nm point-to-point
  • STEM 0.17 nm
JEOL 2100F Cs-Corrected Analytical Electron Microscope
Location: Room G032, Building 22 of The North Campus Research Complex
  • XEDS, PEELS, EFTEM, SAED, NBED, CBED, HREM, STEM, HAADF, Spectrum image/Image spectrum, Diffraction Contrast Imaging

  • CTEM 0.10 nm lattice / 0.19 nm point-to-point
  • STEM 0.10 nm Cs-Corrected HAADF (high angle annular dark field)
JEOL 3011 High Resolution Electron Microscope
Location: Room G024, Building 22 of The North Campus Research Complex

High Resolution Electron Microscopy is phase contrast microscopy of the atomic structure of materials. Specimen stages in these instruments are typically in the high-stability, top-entry configuration. An image intensified TV system allows the observation of the structure images on a TV screen prior to the recording of micrographs. Dynamic experiments are usually recorded onto video tape. A computer controlled image acquisition and analysis package is invaluable for the capture and storage of images of both on-line and off-line analysis and comparison with images calculated with multislice algorithims.

  • Objective Current Stability: 1ppm/minute
  • Objective Focal Length: 2.5 mm
  • Spherical Aberration Coef. (Cs): 0.6 mm
  • Chromatic Aberration Coef. (Cc): 1.3 mm
  • Minimum Focus Step: 1 nm
  • Point-to-Point Resolution: 0.17 nm
  • Lattice Resolution: 0.14 nm
Kratos Axis Ultra X-ray Photoelectron Spectroscopy
Location: Room G019, Building 22 of The North Campus Research Complex

X-ray Photoelectron Spectroscopy (XPS), also known as Electron Spectroscopy for Chemical Analysis (ESCA), uses soft X-rays to produce photoelectrons from the surface layers of atoms in a solid sample. The emitted electrons are analyzed according to their kinetic energy and the spectrum so produced is used to identify the elements present and their chemical states.

  • Spectrum mode: Using the monochromated Al source: 2 x 1 mm with energy resolution ~0.5ev.
  • Small area spectroscopy: ~ several µm.
  • Imaging mode: ~ 900µm x 900µm with spatial resolution ~ 6µm.