Development of a Oxygen Sensor for Marine ... - DTU Nanotech

60 CHAPTER 7. EVALUATION OF RESULTS AND MEASUREMENTS
7.3 Clark Sensor
While there as mentioned was problems with the wire bonding and packaging,
there was one sensor that was both bonded and packaged, and therefore
could be measured upon. The measurements was done using a Gamry FAS2
Femtostat, and a beaker of water with the sensor in it, finally grounded metal
plates was put up around the beaker, in order to create the equivalent of a
Faraday cage. This was done in order to minimize any outside noise (See
Figure 7.4 for a sketch of the setup.
PC
Ground WE CE RE
Potentiostat
Constructed Faraday cage
Figure 7.4: Sketch of the setup used to measure on the Clark sensor, 3 wires
connects the working, reference and counter electrodes respectively
to the potentiostat. The potentiostat collects the data and
sends it to a nearby pc, which translates the signal into a graph.
Unfortunately due to the faulty wirebonding one of the wires broke after
a few test measurements, so no detailed measurements with varying amounts
of dissolved oxygen could be made.
However, as can be seen on Figure 7.5, there is the plateau shaped curve,
which indicates that the sensor itself works. Of course since the a wire
broke during the test measurements, no conclusion can be made in regards
to whether it is measuring the right amount of oxygen or not. Hence further
tests have to be made to confirm this. That the right shape of curve was
obtained, is taken as a good sign, especially as there seems to be no noticeable
internal noise generated.
Beaker
with
Clark
sensor
and
water