Atomic Force Microscopy

Scanning Probe Microscopy techniques are used for studying the surface properties of materials, from the atomic to the micron level. Because of its unprecedented 3-D resolution, the application of SPM techniques are very diverse and continue to evolve in wide variety of disciplines, including fundamental surface sciences, material sciences, biological applications, and many more.

Keysight Technologies 4500 SPM (formerly Molecular Imaging PicoSPM)

Scanning Probe Microscopy (SPM) is a growing collection of techniques that probe the properties of materials at or near their surfaces. Unlike traditional optical microscopies, which rely on electromagnetic radiation to magnify an objectís surface in two dimensions, SPM is a mechanical imaging instrument that measures the three dimensional topography as well as physical properties of the surface with a sharpened probe. SPM applications at the SSSC have found wide spread use in engineering, agriculture, physical sciences, and the health sciences.

The SSSC has a PicoSPM instrument from Molecular Imaging (now under Keysight Technologies, formerly part of Agilent Technologies Ltd.). This instrument can run both scanning tunnelling microscopy (STM) and Atomic Fore Microscopy (AFM) applications. In addition, there are many accessories included with this instrument which has made it a truly multi-disciplinary technique. Some of the available modes include:

  • STM (current mode or height mode imaging)
  • Contact AFM
  • Lateral Force AFM (LFM)
  • Acoustic AC Mode (AAC)
  • MAC Mode™
  • Phase Imaging (AAC and MacMode provides simultaneous amplitude/phase imaging)
  • Current Sensing AFM (CSAFM)
  • Magnetic Force Micrscospy (MFM)
  • Electrostatic Force Microscopy, dc Bias (EFM) (under development)
  • Pulsed Force Mode
  • Electrochemical STM (EC-STM) (current and height imaging)
  • Electrochemical AFM (EC-AFM) (contact, AAC and MAC Mode™ imaging)

Other accessories which expand the instruments capabilities include:

  • Isolation chamber
  • Environmental chamber
  • Heating/cooling stages (effective temperature range of -30 to 250°C)
  • Peristaltic pump for flow-through liquid cell
  • Olympia Inverted Microscope (4X and 20X objectives)
  • CCD camera attachment

Specifications

AFM/STM Scanners
AFM Medium Scanner AFM Small Scanner STM Small Scanner STM Atomic Scanner CSAFM Modules
Range x-y = 30 μm,
z = 7 μm
x-y = 4 μm,
z = 2 μm
x-y = 10 μm,
z = 1.6 μm
x-y = 1 μm,
z = 1 μm
Noise x-y: < 5 Å RMS,
z: < 0.5 Å RMS
x-y: < 1 Å RMS,
z: < 0.1 Å RMS
x-y: < 1 Å RMS,
z: < 0.1 Å RMS
x-y: < 1 Å RMS,
z: < 0.1 Å RMS
Sensitivity 0.1 V/nA 0.1 V/nA 10 V/nA or 0.1 V/nA
MAC Mode Controller
  • Operating Frequency Range: 200 Hz to 1 MHz
  • Typical Operating Frequencies in Air: 90 -130 kHz
  • Typical Operating Frequencies in Liquid: 5 - 45 kHz
  • Oscillation Amplitude in Fluid: typically 5 nm (maximum of 30 nm - peak to peak)
  • Noise: < 0.1 nm RMS
PicoStat Controller
  • ±4.5 V
  • ±6 mA
  • 10 μA to 100 mA full scale (10 nA sensitivity)
  • 10 V full scale (0.3 mV sensitivity)
Heating/Cooling Stages
  • 1x Peltier Stage: -5 to 40°C
  • 3x Peltier Stage: -30°C to ambient temperature
  • High Temperature Stage: Ambient to 250°C
Pulsed Force Mode AFM Frequency Range: 100 Hz - 2 kHz
Amplitude Range: 10 - 500 nm

Settings

The SPM uses the latest SPM control software from Keysight Technologies (PicoView V.4.14), which operates on Windows 7 OS. Image analysis and processing can be completed using Gwyddion (a free SPM processing software): http://gwyddion.net/.

Sample Preparation: Many different types of samples are possible to measure with our SPM. Please contact Jason Maley to discuss.

SPM Consumables: Users are responsible for supplying their own consumables (substrates, probes, sample preparation consumables, etc.). The SSSC keeps a selected few standard contact and AAC mode probes on hand. Users needing specific probes for their work need to supply their own probes. A reliable company is Nanoscience Instruments: http://store.nanoscience.com/store/pc/viewContent.asp?idpage=5

Links