Scanning Electron Microscopy And Microscopy

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1. SCANNING ELECTRON MICROSCOPY Scanning electron microscopy uses a focused beam of electrons to develop an image of the surface. Signal is generated by the interaction of electrons with the surface, which are then detected and perceived to obtain image and desired information related to the characteristics and topography. 1.1. WHY SEM USES ELECTRONS? The resolution power of an eye is about 0.2 mm. However, utilizing a microscope magnify this resolution power. The modern light microscope has a magnifying power of 1000x. The wavelength of the light used can alter the resolving power of the microscope. Visible light as compared to an electronic beam can focus the minute details of the surface. The signals that are derived from electron ample interaction displays information about the physico chemical structure, crystalline morphology and orientation of the arrays of molecules that make up the sample. A dimensional image is generated showing spatial changes in properties (1) . Areas of around 1 to 5 microns can be imaged by using conventional SEM techniques with a magnifying range from 20x to 30,000x. SEM precision to view can be analyzed by keeping in view a fact that it is cable of analyzing a particular sample point. This methodology can be employed for quantitative determination. SEM is advantageous over traditional microscopic technique. SEM has more deep investigational details as compared to the conventional characterization techniques. SEM has much higher resolution
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