Nanowire Based Sensor Boosts Volatile Organic Matter Detection

Nanowires made headline a few days ago because of development of world’s thinnest and indefinitely long Nanowires by Turkish scientists. In the ever innovative world of nanotechnology, Nanowires play an important role as sensors in many different forms. National Institute of standards and measurements (NIST) in collaboration with George Mason University and the University of Maryland has made a Nano sized sensor which is able to detect “harmful pollutants released from Pesticides and paints” aka the volatile organic compounds.

The new nanosized sensor utilizes the common fabrication process as that of computer silicon chips. The sensors are made from Gallium Nitride and Titanium dioxide. Gallium Nitride is used in such nanoscale applications for its wires being 10 micrometers in length and 500 nanometers in breadth. The material constituents of these wires are made sensitive by designing them to have a high surface to volume ratio. The sensitivity can also be observed from the fact that the conventional sensors use a current flowing in the range of milliamps which renders them a little bit uneconomical too as compared to the latest development, while the current design would be have current in just micro amperes, hence consuming less power. This would make them eco friendly too. Moreover, being small in size, they are easily compatible at any interface.


Nanowire

There are two types sensors traditionally used detect volatile compounds. One of them takes the help of organic compound’s reaction with Titanium dioxide. This changes the sensor’s resistance and alters the amount of current flowing through films. This triggers the alarming system and we come to know if the volatile compounds are present in air. These are called the gas sensors. The second variety is of the thin film sensors with operating range above 473K (200oC). However, an important disadvantage seen in this type is that frequent heating and cooling in its working atmosphere has adverse effects on its sensing capabilities. In both the cases, the nanotechnology based current invention is a feasible solution to overcome these drawbacks.

Researchers have designed these sensors so that a single crystal is a single wire. This prevents a cluster of crystals to constitute a nanowire which has an effect of degrading their quality. The nano sized sensor, are proved successfully reliable in laboratory when subjected to real situations. As of now, the sensor can easily detect volatile organic compounds like Toluene, Ethyl benzene and Xylene and Benzene. Scientists now plan to produce an array of such nanowires which can detect a wide range of mixtures of these compounds.

The research will add a reliable tool in detection of such organic pollutants in existing fleet of Volatile compounds detection sensors.

Source: NIST