Spotlight: a focused inspection

Materials World magazine
1 May 2016

Khai Trung Le talks to Ernst Jan Vesseur, SEM Product Marketing Manager at FEI Company, on the forthcoming launch of the Apreo SEM and the company’s contribution to microscopy.

The 50th anniversary of the first commercial SEM was celebrated in November 2015. What are your thoughts on the development of the technology, and how has it remained so important over the years? 

Scanning electron microscopy (SEM) really appeals to the imagination. Being able to zoom from the macroscopic to the nanometre scale is quite spectacular. SEM has also enabled many new scientific applications, surely more than the initial inventors ever imagined, especially in materials science where the properties of many materials are determined by the structure and composition at the nanometre scale that is visible through SEM.

Important contributions made by FEI within SEM include pioneering the development of DualBeam instruments in the early 1990s. The instruments’ unique ability to reveal subsurface structural detail, by making precise cuts with a focused ion beam (FIB) and imaging the exposed surface with a high-resolution SEM, led to rapid acceptance by researchers and engineers in a wide variety of applications, including materials science, microelectronics, life sciences and natural resources.

More recently, in 2014, FEI launched the Teneo VS, the first SEM that uses an in-chamber microtome to serially section the sample and use proprietary deconvolution techniques to further resolve depth information within each slice, allowing reconstructions of the 3D structure of relatively large sample volumes with nanoscale resolution in all directions. 

When combined with a variety of analytical techniques, SEM can extract a wealth of information about the sample, including elemental composition, crystal orientation and size, defects and impurities, dynamic properties, and much more. SEM has proven to be an important scientific tool that is likely to remain at the cutting edge of scientific exploration for many years to come.

How will developments in SEM technology compare with those in the more recent fields of scanning probe and atomic force microscopes, among others?

Like SEM, scanning probe and atomic force microscopes give scientists a window into the nanoworld and all are broadly applicable with the potential for new applications we haven’t yet even envisioned. There are so many things in our daily life that can be traced back to structures or processes that operate at the nanoscale.

FEI currently has eight lines of SEMs. What audience are you hoping to reach with the Apreo?

Some of our current SEMs have a pure industry focus, mining or particle analysis for example. Others are designed to minimise the cost of entry into the field or are designed for extreme performance in specialised applications. Our most recent SEM, the Apreo, to be launched in May, occupies a middle position where both performance and versatility are important. It is designed to deliver the highest performance over the broadest range of applications, while minimising the need for operator expertise. Applications include nanoparticles, insulators, beam-sensitive materials, magnetic materials and many more. In all these sample types, its unique configuration of detectors reveals subtle differences in topography or composition, and extensive automation makes the instrument easy for anyone to use.

How is the lab environment changing?

Multi-user labs are becoming more common now that many of our customers are researchers from multiple disciplines, rather than specialised microscopists. Not every operator is going to be an expert on the tool, and yet productivity is still required. Our new Apreo SEM combines a broad range of expert settings with easy operation for simple tasks.

What changes have been seen in the UK analysis and microscopy sector over the last decade, and how do they compare with international developments? 

UK researchers pushing for new scientific results have been creating new EM applications for decades. The University of Manchester, UK, is a good example. FEI is currently working with a Manchester team to explore multi-scale and multi-modal microscopy – combining SEM with other types of microscopy to expand the types of samples and the range of scales. The results, which include recent 3D work with the Helios plasma FIB, are generating international interest.

Microscopy is employed at almost all levels of materials science, but are there any research or commercial sectors that might be better served by adopting SEMs into their workflow? 

There are many research and industrial sectors that have not yet harnessed the power of nanoscale information. We have many ideas. Please stay tuned… 

Spotlight products:

The UK arm of Hamamatsu Photonics, Japan, has announced the release of two new imaging and detection product lines – the P13243 infrared detector, and the S11637 and S12198 CMOS linear image sensors.

The P13243 indium arsenide antimonite sensors are suitable for the detection and measurement of CO2 and various hydrocarbons in gas sensing and environmental measuring. They are intended as an environmentally-friendly alternative to lead salt detectors, while matching the high sensitivity range between 2.5–5.3µm. As uncooled devices, the range is compatible with pyrometer technology.

Positioned towards spectrometry and image reading use, the S11637 and S12198 have a pixel pitch of 12.5µm and 25µm, respectively. Both feature UV sensitivity, a 10MHz maximum data rate and timing generator. The range is suitable for spectroscopy and image reading. 

USA-based Digital Surf has launched the Mountains 7.3 software suite that enables colourisation of SEM images. Although celebrating SEM as one of the most versatile measuring instruments, Digital Surf has lamented its capture of 2D and black-and-white images, due to its use of electrons rather than photons for visualisation. Mountains 7.3 is touted as performing more than 30 successful mathematical calculations in order to distinguish different objects within images.

Renishaw has announced the next model of the inVia Raman microscope line, the Qontor, which will incorporate the company’s LiveTrack focus tracking technology. With dynamic tracking, Renishaw state that the Qontor will enable analysis of samples previously impractical to study.

Tim Smith, Applications Scientist, commented, ‘Users can now track the surface live while acquiring surface or even subsurface Raman data and later view the Raman image and surface topolography of their sample in 3D.’

Additionally, the Mechanical Engineering department of the University of Tokyo, Japan, has become the latest institute to employ a Renishaw inVia confocal Raman microscope, acquired in their efforts to study graphene and other nanomaterials for use in energy related devices. 

Dr Shohei Chiashi commented, ‘The Renishaw inVia is one of the most frequently used instruments in our university. Scanning Raman imaging spectroscopy is very useful for observing the structure of carbon nanotubes and graphene. It is one of the most important tools for our research. We find it possible to measure Raman images quicky and stably using inVia.’

The inVia has been the principle characterisation tool in two recently published papers, being used to explore single layer hexagonal graphene flakes and to evaluate single-walled carbon nanotubes of different chirality.