Novel Method for Controlled Wetting of Materials in the Environmental Scanning Electron Microscope

Environmental scanning electron microscopy has been extensively used for studying the wetting properties of different materials. For some types of investigation, however, the traditional ways of conducting in situ dynamic wetting experiments do not offer sufficient control over the wetting process. Here, we present a novel method for controlled wetting of materials in the environmental scanning electron microscope (ESEM). It offers improved control of the point of interaction between the water and the specimen and renders it more accessible for imaging. It also enables the study of water transport through a material by direct imaging. The method is based on the use of a piezo-driven nanomanipulator to bring a specimen in contact with a water reservoir in the ESEM chamber. The water reservoir is established by local condensation on a Peltier-cooled surface. A fixture was designed to make the experimental setup compatible with the standard Peltier cooling stage of the microscope. The developed technique was successfully applied to individual cellulose fibers, and the absorption and transport of water by individual cellulose fibers were imaged

Microsensors for in situ electron microscopy applications

With the ongoing miniaturisation of devices, the interest in characterising nanoscale physical properties has strongly increased. To further advance the field of nanotechnology new scientific tools are required. High resolution imaging is one of the key components and when combined with existing characterisation tools such as Atomic Force Microscopy (AFM), Scanning Tunnelling Microscopy (STM) and nanoindentation, this enables direct imaging of real time responses and the possibility to locally probe for instance an individual nanotube. For nanoscale studies, electron microscopy and in particular Transmission Electron Microscopy (TEM) is one of the few tools with sufficiently high imaging resolution. The main challenge of such in situ instruments is the restricted space available in the millimetre sized pole piece gap of a TEM. In this work the design, fabrication and integration of two types of in situ TEM sensors is presented. The sensors are used in an in situ TEM-Nanoindentation and an in situ TEM-AFM system, providing direct and continuous force measurements. The nanoindenter force sensor utilises capacitive read out and the AFM sensor read out is based on piezoresistive detection. Both sensors were fabricated using silicon micromachining. Silicon micromachined devices have the advantage of inherently small footprint, which makes them suitable for the millimetre sized pole piece gap of the TEM. The nanoindenter force sensor operates in force ranges up to 4.5 mN and a resolution of 0.3 \ub5N has been measured in the TEM. The AFM sensor has a force range up to 3 \ub5N with a resolution of 15 nN at 5 kHz bandwidth. Both sensor geometries are designed such that they fit in most TEM models. The force sensors have been integrated into TEM-Nanoindenter and TEM-AFM specimen holders. The systems have been evaluated with measurements on aluminium film and nanowires. Furthermore, the AFM sensor has also been used inside a Scanning Electron Microscope (SEM) and an Environmental SEM. Studies of tool steel and living yeast cells have been performed. These measurements verify proper operation and demonstrate possible application areas of the TEM-Nanoindenter and the TEM-AFM

Microsensors for in situ electron microscopy applications

With the ongoing miniaturisation of devices, the interest in characterising nanoscale physical properties has strongly increased. To further advance the field of nanotechnology new scientific tools are required. High resolution imaging is one of the key components and when combined with existing characterisation tools such as Atomic Force Microscopy (AFM), Scanning Tunnelling Microscopy (STM) and nanoindentation, this enables direct imaging of real time responses and the possibility to locally probe for instance an individual nanotube. For nanoscale studies, electron microscopy and in particular Transmission Electron Microscopy (TEM) is one of the few tools with sufficiently high imaging resolution. The main challenge of such in situ instruments is the restricted space available in the millimetre sized pole piece gap of a TEM. In this work the design, fabrication and integration of two types of in situ TEM sensors is presented. The sensors are used in an in situ TEM-Nanoindentation and an in situ TEM-AFM system, providing direct and continuous force measurements. The nanoindenter force sensor utilises capacitive read out and the AFM sensor read out is based on piezoresistive detection. Both sensors were fabricated using silicon micromachining. Silicon micromachined devices have the advantage of inherently small footprint, which makes them suitable for the millimetre sized pole piece gap of the TEM. The nanoindenter force sensor operates in force ranges up to 4.5 mN and a resolution of 0.3 \ub5N has been measured in the TEM. The AFM sensor has a force range up to 3 \ub5N with a resolution of 15 nN at 5 kHz bandwidth. Both sensor geometries are designed such that they fit in most TEM models. The force sensors have been integrated into TEM-Nanoindenter and TEM-AFM specimen holders. The systems have been evaluated with measurements on aluminium film and nanowires. Furthermore, the AFM sensor has also been used inside a Scanning Electron Microscope (SEM) and an Environmental SEM. Studies of tool steel and living yeast cells have been performed. These measurements verify proper operation and demonstrate possible application areas of the TEM-Nanoindenter and the TEM-AFM

Expanding in situ TEM instrumentation with MEMS technology

Nanofactory Instruments is a spin off company from Chalmers University of Technology which offers instrumentation for nano-scale electrical and mechanical characterization correlated with real time imaging in situ in transmission electron microscopes (TEM).As a core component in the company’s product portfolio, proprietary MEMS sensors for quantitative force measurements on the nano-Newton and micro-Newton scales were developed. As a result of the introduction of MEMS technology into the products, added value was created and the company has now established a leading position in the market