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
Fleischer.
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.
CI NEWS BUREAU