Review Article

Recent Progress in Ohmic/Schottky-Contacted ZnO Nanowire Sensors

Figure 15

(a) SEM image of the morphology of the as-synthesized ZnO NWs. The insert is a high-magnification image of an individual wire and Optical microscopy. (b) Digital image of a ZnO NW pH sensor. (c) The response of the sensor to the pH varying from 3 to 12, no external strain was applied, just like traditional NW based sensors. (d) The repeatability of the ZnO sensor pH sensor at pH 5 and 12. The signal level and the sensitivity of the sensor are increased by the piezotronics effect. (e) The output signal of a sensor in a buffer solution with pH = 5 when the strain is “off” (blue) and “on” (red). The signal is increased about 1500 times when a compressive strain ofε = −0.92% was applied. (f) The response of the sensor to the pH varying from 3 to 12, when the device is strain off (red) and on (blue) [17]. Copyright 2013, American Chemical Society.
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