Using Scanning Electron Microscopy ( Sem ) And Energy Dispersive Spectroscopy

1149 Words Dec 11th, 2016 5 Pages
Using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) images and spectra were obtained from various samples of silica and platinum on silica. Each sample contains unique structures which were prepared by etching the surface of silica in different conditions.
A scanning electron microscope is a type of electron microscope that produces images of topography and composition by scanning a sample with a focused beam of electrons. Samples can be observed in high vacuum, low vacuum, in wet conditions, or at elevated temperatures. The images in this paper were obtained by the detection of secondary electrons that were emitted by atoms excited by the primary electron beam. The primary beam scans in a raster fashion, making horizontal passes across the x-axis one at a time. This allows the detector to display the information into the image on pixel at a time in synchronized manner. The number of secondary electrons that can be detected depends on the surface of the sample. By use of a special detector, the number of secondary electrons collected gives an image displaying the topography of the surface. Secondary electrons are emitted by the atoms near the surface of the sample. The electron beam excites these atoms giving them sufficient energy to emit an electron in an inelastic, loss of kinetic energy, fashion. The brightness of the signal depends on the number of secondary electrons that reaches the detector. Signals with varying brightness in the array…

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