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Microscope: Scanning Probe, STM/AFM, PicoSPM

Scanning tunneling microscopy image of a conductive nanowire produced by bacteria Shewanella oneidensis
Scanning tunneling microscopy image of a conductive nanowire produced by bacteria Shewanella oneidensis Full Image (jpg 63 kb)

Quick Specs

  • Allows imaging of air and moisture-sensitive samples under controlled conditions
  • Capable of tetecting currents from 1pA to 100 nA
  • Can perform I/V spectroscopy in STM and current-sensing AFM modes

EMSL's Molecular Imaging, Inc. PicoSPM™ scanning tunneling microscopy (STM)/atomic force microscopy (AFM) supports a wide range of scanning-probe techniques used to examine surfaces of diverse materials such as conductive and nonconductive minerals, bacterial biofilms, and self-assembled protein monolayers. The microscope incorporates temperature control, fluid cells, and an environmental chamber that collectively allow imaging of air- and moisture-sensitive samples under controlled conditions.

The microscope supports most AFM imaging techniques, including contact and intermittent-contact modes of operation. The intermittent-contact mode is magnetically driven (MAC™ mode). In addition, PicoSPM incorporates the capability to examine conductive materials by STM and by current-sensing AFM. The microscope can detect currents ranging from 1 pA to 100 nA and can perform I/V spectroscopy measurements in both STM and current-sensing AFM modes.

The microscope is equipped with Teflon fluid cells for in situ imaging in liquids. The cells can hold aqueous and nonaqueous media and have flow-through capabilities, allowing users to perform real-time kinetic experiments while imaging the samples. Coupled with the electrochemical unit that includes a low-noise potentiostat/galvanostat, fluid cells can be used for imaging under electrochemical control both in the AFM and in the STM modes of operation.

Two temperature-controlled sample mounts can heat and/or cool samples from -30°C to 250°C. Additionally, the microscope is equipped with an environmental chamber that can be used to maintain samples in a controlled atmosphere during imaging. This allows users to maintain complete control of the imaging environment, and creates the capability to perform in situ kinetic measurements on a variety of systems from minerals to biological systems.

  1. Subsurface Synthesis and Characterization of Ag Nanoparticles Embedded in MgO.
  2. Very Stable Electron Field Emission From Strontium Titanate CoatedCarbon Nanotube Matrices With Low Emission Thresholds.
  3. Oxide Melt Solution Calorimetry of Fe2+ -bearing Oxides and Application to the Magnetite - Maghemite (Fe3O4-Fe8/3O4) system.
  4. Surface Science Analysis of GaAs Photocathodes Following Sustained Electron Beam Delivery.
  5. Diffusion and Adsorption of Uranyl Carbonate Species in Nanosized Mineral Fractures.
  1. New finding shows a research area to expand in EMSL Radiochemistry Annex (Promising Science for Plutonium Cleanup )
  2. Shewanella proteins could be used to generate energy or immobilize contaminants (Wired Microbe Conducts Electricity)
  3. Scientists connect previous studies on electron transport in hematite (Grow Iron, Slow Pollution)