Gas sensor based on graphene.
Gas sensor based on graphene has high sensitivity. He is able to catch even one molecule of the gas or impurity.
Graphene has unique properties due to which it can be used as a gas sensor in any gas. Such properties are: high adsorptive capacity and high conductivity. Graphene is able to sense the adsorption of even a single molecule. From graphene to 70 times the mobility of electrons is higher than that of silicon. The speed of electrons in graphene is 10 000 km/s, although in a conventional conductor, the velocity of the electrons of order 100 m/s. Graphene has almost no resistance.
Adsorption of a small amount of impurities and gases on the surface of graphene leads to the fact that graphene changes its overall electrical conductivity. There is a decrease or increase of the electric resistance film, which can be measured.
Sorption of molecules of gas or impurities on the surface of graphene is completely reversible. To clean the graphene detector is passed through it a current of about 10 mA. This is enough to heat the graphene structure so that there was desorption of the gas particles or impurities. The mechanism of purification does not affect the efficiency of the detection of gases. Therefore, the graphene sensors can be used repeatedly without detriment to the detection process.
Currently, the developed gas sensor with an active element of graphene for the detection of ammonia (NH3), nitrogen oxide (NO2) and carbon dioxide (CO2).
Gas sensor based on graphene in contrast to the other sensors is characterized by its small size.
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