Capabilities

Introduction

Electron microscopes are usually associated with high vacuum conditions and special specimen preparation procedures.  Our scanning electron microscopes (SEMs) and scanning probe microscopes (SPMs) offer new possibilities to view samples in any environment including liquids.  The Centre incorporates the UK’s first ultra high resolution 3D environmental SEM (3D ESEM), allowing 3D imaging of soft matter, such as cell tissue, with nanoscale resolution.  Incorporated within this microscope is the UK’s first WetSTEM detector, allowing thin sections to be viewed in transmission while maintaining the sample in a hydrated state.  For the first time in the UK we incorporate an SPM inside the SEM chamber, combining all of the imaging and manipulation capabilities together with the 3D ESEM. As well as the most sophisticated scanning electron microscope currently available we also have the simplest; the UK’s first ultra-small, ultra-fast ‘desk-top’ SEM.  This revolutionary concept allows almost any sample to be viewed at up to 20,000´ magnification in less than 30 seconds and is as easy to use as a digital camera.

Nano-scale imaging

Image resolution in the nanometre range is possible on the surface of samples (SEM and SPM), in transmission (TEM and STEM) and in 3D reconstruction (FIB SEM).  For example: crystal lattice imaging, single (large) molecules such carbon nanotubes and protein molecules.  Achievable resolution is dependent on sample preparation and image contrast.

Soft solids

Hydrated sample surfaces can be imaged at high resolution in the environmental SEM and in the SPM.  Internal structure of hydrated samples can be imaged in the WetSTEM.  Fully hydrated samples can be viewed without any preparation.  Non-conductive samples can be imaged without coating or high vacuum conditions.  Beam sensitive or volatile samples can be imaged at cryogenic temperatures in the Cryo-SEM.

Dynamic studies

Hydration or other environmental conditions can be varied and changes viewed in real time using the ESEM, including liquid-solid interactions.

3D imaging

Site-specific cross-sections can be made in vacuum stable samples (including cryogenically stabilised soft solids) using the FIB milling.  Sequential cross-sections can be imaged and reconstructed into full three dimensional representations to reveal internal structure using the automated ‘slice-and-view’ software. 

Focussed Ion Beam specimen preparation

Thin electron transparent cross-sections can be milled from site-specific locations in vacuum stable samples (including cryogenically stabilised soft solids) using the automated TEM-prep software.  Samples can be transferred to sample grids for viewing in the TEM or STEM using an in-situ manipulator.

Patterning and lithography

Both the FIB and electron beam can be used for fine feature lithography.  The FIB can also be used to directly pattern surfaces, including non-conductors, and to deposit platinum for nanofabrication.

Nanomechanics

Mapping of surface stiffness can be achieved using the SPM.  Direct measurements of mechanical forces can be made using the force sensor formed by the SPM cantilever, including molecule-molecule interaction forces. 

Molecule specific imaging

By grafting specific molecules to the tip of an SPM cantilever, the interaction with molecules or receptor sites in the specimen surface can be mapped.

Rapid imaging

The ‘Phenom’ SEM allows surface imaging of almost any sample type without preparation in under a minute.  Thin, electron transparent, samples can be viewed at up to 6 at a time in the STEM within a few minutes, before more detailed examination in the TEM.

Analysis

Analysis of chemical elements in the specimen can be achieved in the electron microscopes (SEM, ESEM, STEM, TEM) using characteristic x-ray spectroscopy (EDS) for all elements except Hydrogen and Helium. Mapping of the concentration and position of elements can be performed in the SEM, ESEM and STEM.  Precise and fully quantitative analysis of elements can be achieved in the SEM using the WDS spectrometer.  Crystalographic orientation at the specimen surface can be determined and mapped in the SEM using EBSD.