Material Characterization

Along with material depositions and nanofabrication, we also provide service of material characterization using multiple techniques. Some of our most demanded techniques are X-Ray Photoelectron Spectroscopy (XPS), Ultraviolet Photoelectron Spectroscopy (UPS) and Scanning Elentron Microscope (SEM).

X-Ray Photoelectron Spectroscopy

X-ray photoelectron spectroscopy (XPS), also known as electron spectroscopy for chemical analysis (ESCA), is a technique for analyzing the surface chemistry of a material. XPS can measure the elemental composition, empirical formula, chemical state and electronic state of the elements within a material. XPS spectra are obtained by irradiating a solid surface with a beam of X-rays while simultaneously measuring the kinetic energy and electrons that are emitted from the top 1-10 nm of the material being analyzed. A photoelectron spectrum is recorded by counting ejected electrons over a range of electron kinetic energies. Peaks appear in the spectrum from atoms emitting electrons of a particular characteristic energy. The energies and intensities of the photoelectron peaks enable identification and quantification of all surface elements (except hydrogen).

Ultraviolet Photoelectron Spectroscopy

Ultra violet photoemission spectroscopy (UPS) is analogous to XPS but the excitation source is a helium discharge source. Depending on the operating conditions of the source the photon energy can be optimised for He I = 21.22eV or He II = 44.8eV which is significantly lower energy than Al or Mg Kα used in XPS. As with XPS the BE is related to the measured photoelectron KE by the simple equation; BE = hν - KE where hv is the photon (x-ray) energy. The consequence of this lower photon energy is that only the low binding energy valence electrons may be excited using the He source. A further consequence of the low photon energy is UPS is more surface sensitive than XPS and thus very sensitive to surface contamination. UPS is very useful as a technique to determine the work function of the material being analysed and is finding increasing application in characterisation of organic and inorganic photovoltaics, organic LEDs.

Scanning Electron Microscope

A scanning electron microscope (SEM) scans a focused electron beam over a surface to create an image. The electrons in the beam interact with the sample, producing various signals that can be used to obtain information about the surface topography and composition.

The scanning electron microscope (SEM) uses a focused beam of high-energy electrons to generate a variety of signals at the surface of solid specimens. The signals that derive from electron-sample interactions reveal information about the sample including external morphology (texture), chemical composition, and crystalline structure and orientation of materials making up the sample. In most applications, data are collected over a selected area of the surface of the sample, and a 2-dimensional image is generated that displays spatial variations in these properties. Areas ranging from approximately 1 cm to 5 microns in width can be imaged in a scanning mode using conventional SEM techniques (magnification ranging from 20X to approximately 30,000X, spatial resolution of 50 to 100 nm). The SEM is also capable of performing analyses of selected point locations on the sample; this approach is especially useful in qualitatively or semi-quantitatively determining chemical compositions (using EDS), crystalline structure, and crystal orientations (using EBSD). The design and function of the SEM is very similar to the EPMA and considerable overlap in capabilities exists between the two instruments

If you would like to get material characterization of your nanocoatins, please contact at "order@fourien.com" with the service ID as "MatChar 430"