Dec 24 2010
Imec and Holst Centre have devised a new sensing system for calculating traces of NO2 that helps detecting the rate of environmental pollution arising from traffic and combustion motors.
These sensors work on vertical InAs nanowires and a unique sensor encompassing a total of 500 such nanowires that are highly responsive to NO2 concentrations or even lesser than 100ppb at ambient temperature.
The nanowires embedded in the sensors are of 3ìm in length and 50nm to 100nm in width. These sensors are made of InAs and aid gas detecting applications. The electron build up layer at its surface, makes it responsive to the accumulated charges and the gas molecules adhere to the nanowire surface, altering the charge passing through nanowires. The nanowires are semi conductive in nature and are joined ohmically by an air bridge structure which empties the nanowire surface for gas adsorption. The tiny bandgap of InAs aids ohmic contacts. By simply supplying a robust current, the sensors can be reorganized.
In the novel nanowire technology, vertical nanowires are electrically linked to the areas on the substrate where they are developed, whereas in other technology, the nanowires are placed on the substrate after developing anywhere. The innovative sensing nanowires can work without heating, producing them to be more power-effective.
This novel gas sensor has been devised in Holst Centre, for delivering lesser power sensing units. Further, the scientists will improve the sensitivity and detection selectivity of the sensor. The sensor will also be made efficient to differentiate NO2 as well as NO gases. Apart from these, advanced fabricating methodologies will also be studied for developing economical silicon substrates, producing effective systems.
Source: http://www.imec.be