Mobile electronic devices learn to smell

DQC Bureau
New Update

Siemens researchers have succeeded in developing novel mini-sensors that can

detect gases and smells. Mobile electronic devices will be used in future to

measure the ozone level in the air and warn if it exceeds the limits, or emit a

signal in reaction to the smell of burning or leaking gas. A possible

application would be a portable warning device for travelers that would wake

them up in case of danger when they were asleep.


"We've discovered new functional principles and then developed new

materials to exploit these principles industrially using all the potential

offered by nanotechnology," says Siemens researcher Dr Maximilian Fleischer,

explaining the concentrated high tech packed onto a tiny area. It takes highly

advanced scanning electron microscopes to reveal the structures of the new

materials. The tiny sensors developed from these materials can effectively trace

even the smallest quantities of gas. "Our ceramic sensor chips are less

than a millimeter in size," states Maximilian. "Although you can

barely see them with the naked eye these sensors incorporate a large number of

miniaturized functions in which chemical reactions take place."

Different sensor types have been developed for the different gases. FET gas

sensors operate at normal room temperature, whereas metal oxide gas sensors

detect the presence and concentration of individual gases as soon as they are

heated to several hundred degrees C. The gases react with the sensor material

which is combined with silicon technology. This system reads out the chemical

changes electronically, amplifies the electronic signal and further processes

it. If the sensor material is subsequently exposed to the ambient air again it

regenerates itself. These sensors can also be used in contaminated environments.

"We have sensors that are extremely stable due to the high local

temperatures and can automatically burn off any contamination," said


Thanks to their small size, low production costs and economical energy

consumption - anything between a few 100mW and less than 1mW depending on the

design of the sensor - the new gas sensors are of interest for a large number of

applications for which no technical solution has existed before.