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Study of parasitic resistance effects in nanowire and nanoribbon biosensors.

Zeimpekis I, Sun K, Hu C, Thomas O, de Planque MR, Chong HM, Morgan H, Ashburn P - Nanoscale Res Lett (2015)

Bottom Line: Measurements of pH with polysilicon nanoribbon biosensors are used to demonstrate a reduction in sensitivity as the sensor length is reduced.These results are interpreted using a simple empirical model, which is also used to demonstrate how the sensitivity degradation can be alleviated by a suitable choice of sensor window length.Furthermore, a differential sensor design is proposed that eliminates the detrimental effects of parasitic resistance.

View Article: PubMed Central - PubMed

Affiliation: Zepler Institute, School of Electronics & Computer Science, University of Southampton, Southampton, SO17 1BJ UK.

ABSTRACT
In this work, we investigate sensor design approaches for eliminating the effects of parasitic resistance in nanowire and nanoribbon biosensors. Measurements of pH with polysilicon nanoribbon biosensors are used to demonstrate a reduction in sensitivity as the sensor length is reduced. The sensitivity (normalised conductance change) is reduced from 11% to 5.5% for a pH change from 9 to 3 as the sensing window length is reduced from 51 to 11 μm. These results are interpreted using a simple empirical model, which is also used to demonstrate how the sensitivity degradation can be alleviated by a suitable choice of sensor window length. Furthermore, a differential sensor design is proposed that eliminates the detrimental effects of parasitic resistance. Measurements on the differential sensor give a sensitivity of 15%, which is in good agreement with the predicted maximum sensitivity obtained from modeling.

No MeSH data available.


Normalized conductance change (sensitivity) measured after changes of pH for two sensors with different sensing window lengths.
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Fig1: Normalized conductance change (sensitivity) measured after changes of pH for two sensors with different sensing window lengths.

Mentions: Figure 1 shows the normalized conductance change as a function of time when the biosensor is exposed to different pH buffers for two different TFT biosensors with sensing window lengths of 51 and 11 μm. For the 51 μm window sensor, the conductance increases by approximately 11% for a pH change of 6 units, from pH 9 to pH 3. A subsequent increase in pH results in a decrease of conductance back to the original value. A similar, though smaller, trend is observed for the sensor with the shorter sensing window of 11 μm with a conductance increase of 5.5% from pH 9 to pH 3. Therefore, the longer 51 μm sensor has a higher sensitivity than the shorter 11 μm sensor. This indicates a relation between sensitivity and sensing window length.Figure 1


Study of parasitic resistance effects in nanowire and nanoribbon biosensors.

Zeimpekis I, Sun K, Hu C, Thomas O, de Planque MR, Chong HM, Morgan H, Ashburn P - Nanoscale Res Lett (2015)

Normalized conductance change (sensitivity) measured after changes of pH for two sensors with different sensing window lengths.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4385057&req=5

Fig1: Normalized conductance change (sensitivity) measured after changes of pH for two sensors with different sensing window lengths.
Mentions: Figure 1 shows the normalized conductance change as a function of time when the biosensor is exposed to different pH buffers for two different TFT biosensors with sensing window lengths of 51 and 11 μm. For the 51 μm window sensor, the conductance increases by approximately 11% for a pH change of 6 units, from pH 9 to pH 3. A subsequent increase in pH results in a decrease of conductance back to the original value. A similar, though smaller, trend is observed for the sensor with the shorter sensing window of 11 μm with a conductance increase of 5.5% from pH 9 to pH 3. Therefore, the longer 51 μm sensor has a higher sensitivity than the shorter 11 μm sensor. This indicates a relation between sensitivity and sensing window length.Figure 1

Bottom Line: Measurements of pH with polysilicon nanoribbon biosensors are used to demonstrate a reduction in sensitivity as the sensor length is reduced.These results are interpreted using a simple empirical model, which is also used to demonstrate how the sensitivity degradation can be alleviated by a suitable choice of sensor window length.Furthermore, a differential sensor design is proposed that eliminates the detrimental effects of parasitic resistance.

View Article: PubMed Central - PubMed

Affiliation: Zepler Institute, School of Electronics & Computer Science, University of Southampton, Southampton, SO17 1BJ UK.

ABSTRACT
In this work, we investigate sensor design approaches for eliminating the effects of parasitic resistance in nanowire and nanoribbon biosensors. Measurements of pH with polysilicon nanoribbon biosensors are used to demonstrate a reduction in sensitivity as the sensor length is reduced. The sensitivity (normalised conductance change) is reduced from 11% to 5.5% for a pH change from 9 to 3 as the sensing window length is reduced from 51 to 11 μm. These results are interpreted using a simple empirical model, which is also used to demonstrate how the sensitivity degradation can be alleviated by a suitable choice of sensor window length. Furthermore, a differential sensor design is proposed that eliminates the detrimental effects of parasitic resistance. Measurements on the differential sensor give a sensitivity of 15%, which is in good agreement with the predicted maximum sensitivity obtained from modeling.

No MeSH data available.