2009 Advanced Laboratories Conference Abstract Detail Page
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||Transmission Electron Microscope
||In this experiment we will explore the use of transmission electron microscopy (TEM) to take us into the world of ultra-small structures. This is the regime between 1000 Å and atomic dimensions in which the continuing miniaturization of integrated electronics is being pursued. It is also a very important region for structural biology. These length scales are far below the limit where the resolution of conventional optical microscopy becomes dominated by the wavelength of visible light (~5000 Å). The transmission electron microscope (or TEM), first invented in the late 1930's, has now developed into the technique of choice for micro-structural studies in a wide range of fields: materials research, biophysics, polymer science, mineralogy, and health sciences, to name a few.
In the first part of the experiment, you will get a feel for the capabilities and immense resolving power of TEM by imaging some samples of DNA. We will measure the diameter and pitch of DNA's famous double-helix structure. In the second part of the experiment, we will use TEM to study some "quantum well" structures made from ultra-thin layers of Silicon and alloyed Silicon-germanium. We will determine the point spread function of the Philips 420 electron microscope and measure, at the highest magnification, the width of a quantum well and the abruptness of its boundaries. These are key quantities that determine the spectrum of electronic energy levels of the quantum well. The Si/Si-Ge samples will also demonstrate the capability of TEM to obtain selected-area diffraction patterns, from which detailed structural information can be obtained at atomic dimensions.
||Session V - Parallel Workshops
Faculty or Staff
University of Michigan