| On the way to artificial nose |
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Vibrating molecules Nanosaiten catch  Nanosaite as a sensor molecule Nanoscientists from Munich are an important step forward towards the artificial nose succeeded. You have Nanosaiten silicon nitride, which as probe individual molecules erschnuppern can. Artificial noses are so-called Nano-Electromechanical Systems (NEMS), chips, on which many Nanosaiten thin with a diameter of 100 nanometers (one ten thousandth millimeter), are appropriate. These strings are coated so that a particular molecule places attract. To measure the strings into vibrations. When a molecule to determine the string vibrates measurably heavier and slower, "A measurement of the oscillation period, thus allowing chemical substances molecule demonstrate exactly," says Quirin Unterreith Meier, a physicist at the Ludwig-Maximizing- Universidad (LMU) in Munich. According to this principle could be a powerful chemical detection system - an artificial nose just - to be built. On a chip the size of a fingernail would easily place several thousand strings. The practical implementation is still some problems. Thus although Nanosaiten magneto mechanical of conductive materials, piezo-electric or electro to swing the market. The strings must be made of metal or metal coated. Such Nanosaiten swing but not enough to serve as a sensitive probe to detect single molecules can, The Munich scientists have now Nanosaiten silicon nitride designed to deliver better results. Because this material is not conductive, it would require a different approach to the strings to vibrate. This problem led to the scientists, by the principle of dielectric interaction advantage: Two gold electrodes generate an electric field that the strings into vibrations. These are supported by two other electrodes is measured. The building had the scientists in the etching process produced, explains the physicist Eva Weig. It is easily possible to him "in ten thousand repeat on a chip" to implement. Except as an artificial nose are more applications for silicon nitride Nanosaiten conceivable, for example in measurement or as a clock for clock. |
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