Philips PW3040 X-Ray Diffractometer (XRD)

X-ray fluorescence, determines the concentrations of elements within the sample (mixture of solid or powdered material). The properties of solid material, however, are not determined by the relative amounts of elements alone, but also by the arrangement of the atoms within the crystallites. When a beam of X-ray photons penetrates through a matter, scattering, furthermore, diffraction occurs. The diffraction pattern characteristically depends on the structure of the matter. This diffraction pattern is therefore a 'fingerprint' of the structure of examined sample. Therefore, X-ray difractometry (XRD) is powerful and versatile nondestructive analytical techniques for the identification and quantitative determination of crystalline solid phases (atomic arrangements) within solid and powdered samples. In fact, it is the only technique that can distinguish between phases.

• Samples can be in dry powder, film, plate and paste forms.

Applications include: Qualitative analysis: identification the structures of polycrystalline and amorphous materials, such as geological and environmental samples; Quantitative analysis: determination the relative concentrations of each of the components in a multi-component mixture; Structure of alloys; Stress determination in metals; Determination of particle size: The angular spread of the reflection from a crystal plane is affected not only by the perfection of the crystal but also by the size of the crystal. The half height width of a reflection in a powder diffractogram can be used as quantitative measure of the mean particle size of the sample; Identification and raw material evaluation: For complex materials (cement powder, sands, clays), the powder pattern will be correspondingly complex, however, it will be characteristic of the material. Although the pattern cannot be analyzed for each of the individual components, similar materials will always exhibit similar patterns.

. Special-Purpose Optical Microscope

Omicron Scanning Near Field Optical Microscope (TwinSNOM)

A typical optical microscope cannot resolve images smaller than the wavelength of light used to illuminate the specimen. The near-field microscope is an advanced optical microscope that is able to resolve details much smaller than the wavelength of visible light. This high resolution is achieved by passing a light beam through a tiny hole (aperture) at a distance from the specimen about a few nanometer and by detecting the reflected (or transmitted) light for image formation. The resolution of the SNOM image is defined by the size of the aperture, typically 50 - 100 nm, i.e. smaller than half the wavelength of visible light. Light cannot pass through such an aperture, however an evanescent field, the optical near-field, protrudes from it. The optical near-field decays exponentially with distance, and is thus only detectable in the immediate vicinity of the tip.

Among SNOM applications is a surface topography. SNOM can measure sample surface topographical properties without touching the surface at around 100 nm scale. The images measured by SNOM are optical images that are different from images measured by AFM. This advantage can sometimes be important. For instance, the sample is composed of two identical components in shape and size, but optical properties are distinct. SNOM is capable of distinguishing the distribution of these two components in the sample. Another advantage of SNOM over AFM is measuring inner structure of samples.

. Scanning Probe Microscope

Digital Instrument Nanoscope III MultiMode Scanning Probe Microscope (SPM/AFM)

Scanning probe microscopy (SPM) consists of a family of microscopy forms where a sharp probe is scanned across a surface and some probe/sample interactions are monitored. The SPM has become popular because of the volume of nanometer-scale information it provides. Unlike conventional microscopes that provide direct images of an object, scanning probe microscopes provide data in the form of topographic relief images. Atomic force microscopy (AFM) is one of the forms of SPM. AFM is used to image and explore nanoscale features and structures of surfaces, both in air and in liquid. Topography of surfaces can be obtained normally by two different modes, contact mode and tapping mode. However, tapping mode is normally used for soft, adhesive or fragile samples since imposed force on samples by tapping mode is much more weak than that by contact mode. If the sample is conductive, scanning tunneling microscopy (STM) is recommended to get images with higher resolution. Imaging surfaces in the liquid can be used to study liquid-solid interfacial phenomena, for example, the adsorption of colloid particles, polymer, and DNA and protein molecules.

Our AFM can be used to do (a) force modulation imaging, (b) lateral force imaging, (c) magnetic force imaging, (d) electric force imaging, (e) nano indentation
(a) Force modulation imaging is a scanning probe microscopy technique that identifies and maps differences in surface stiffness or elasticity.
(b) Lateral Force imaging is a scanning probe microscopy technique that identifies and maps relative differences in surface frictional characteristics.
(c) Magnetic force imaging is an extension to the basic topographical mapping capabilities. It is useful for measuring magnetic information for storage media, magnets and magnetic materials.
(d) Electric force imaging is an extension to the basic mapping capabilities as well. It is used to monitor continuity and electric field patterns on samples such as semiconductor devices and composite conductors.
(e) Diamond tip is used for indentation, mechanical properties of materials can be examined by nanoindentation study. In additon, we have fluid module and electrochemical module.