Microscope's misleading tips.Although atomic-force microscopes reveal atomic-scale details not seen with many other imaging techniques, Swiss physicists warn that those details may not always be real. These microscopes map the landscape of a surface by monitoring fluctuations in the forces between atoms in a very fine imaging tip and those in the material under investigation. Scientists have used the microscopes to study active molecules and to move molecules around (SN: 3/17/90, p.165). But P. Grutter and colleagues at the University of Basel The University of Basel (German: Universität Basel) is located at Basel, Switzerland. History Founded in 1459, it is Switzerland's oldest university. in Switzerland have discovered that imperfections in these tips can lead to spurious results. In the June 1 APPLIED PHYSICS LETTERS Applied Physics Letters is a weekly peer-reviewed scientific journal published by the American Institute of Physics devoted to the publication of new experimental and theoretical papers about applications of physics to science, engineering, and modern technology. , the researchers show how one atomic-force microscope tip misrepresented the topography of a diamond film. Examination with a scanning electron microscope scan·ning electron microscope n. Abbr. SEM An electron microscope that forms a three-dimensional image on a cathode-ray tube by moving a beam of focused electrons across an object and reading both the electrons scattered by the object and and with a scanning tunneling microscope scanning tunneling microscope, device for studying and imaging individual atoms on the surfaces of materials. The instrument was invented in the early 1980s by Gerd Binnig and Heinrich Rohrer, who were awarded the 1986 Nobel prize in physics for their work. revealed that the film surface consists of sharp tips and steep facets formed by oriented crystals. But the atomic-force microscope depicted the surface as truncated pyramids. The microscope's tip had that same squared-off shape. Tips are etched in batches from silicon wafers. The scientists found three flawed tips in a batch of 10 and concluded that dust or imperfect processing led to the bad tips. They suggest that scientists characterize and calibrate To adjust or bring into balance. Scanners, CRTs and similar peripherals may require periodic adjustment. Unlike digital devices, the electronic components within these analog devices may change from their original specification. See color calibration and tweak. tips before using them. |
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