Low-cost, sensitive CO sensor from IISc
7th
August:
Indian
Institute of Science researchers have developed a highly sensitive
nanometre-scale carbon monoxide sensor by employing an innovative fabrication
technique. It is known that carbon monoxide (CO) can have adverse effects on
the health of people exposed to it. Hence, it becomes necessary to have good,
low-cost carbon-monoxide sensors.
Typically, a
sensor would be a thin, current carrying plate whose resistance changes on
exposure to carbon monoxide. This in turn changes the value of the current
flowing through it. This change when measured indicates the level of carbon
monoxide in the air. Most available sensors are in the micrometer range, a
nanometer-sized detector would have a higher sensitivity, but the cost of
manufacturing it goes up as the size decreases. This is where the work of C.S.
Prajapati and coworkers of Indian Institute of Science comes in.
CO sensor
- The
nanometer-sized sensor was made using zinc-oxide (ZnO) nanostructure on a
siliconchip with tiny polystyrene beads
- These
beads were first added on the on the oxidised chip in a hexagonal
close-packed structure
- Vacuum
is maintained between the silicon wafer and beads
- When
a high voltage is applied during this stage, it etches away the surfaces
of the beads forms a desired uniform gap among the beads which makes ZnO
is deposited on the system
- The
spaces between the beads creates a nano-mesh that can function as a
nanosenor
- The
nanometre-scale Carbon Monoxide (CO) sensor is able to detect a difference
in CO level as low as 500 parts per billion (ppb)
- It
can selectively respond to CO even in the presence of other gases
- The
sensor was developed using novel fabrication technique that does not
involve costly and time consuming lithography technology that is used
until now
What is Carbon Monoxide (CO)?
- CO
is a colorless, odorless gas
- It
is harmful when inhaled in large amounts
- The
greatest source of CO is internal combustions (IC) engines of cars, trucks
and other vehicles or machinery that burn fossil fuels
- Breathing high concentration of CO reduces the amount of oxygen that can be transported in the blood stream to critical organs like the heart and brain.
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