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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.


Schematic illustration of the differential design and measurement configuration. Two sensors are used for the differential measurement, with long and short sensing windows. The sensors are otherwise identical.
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Fig5: Schematic illustration of the differential design and measurement configuration. Two sensors are used for the differential measurement, with long and short sensing windows. The sensors are otherwise identical.

Mentions: To maximize the sensitivity, a differential biosensor design is proposed in Figure 5, which measures the difference in resistance between the two biosensors with different sensor window lengths. As the two biosensors have equal values of parasitic resistance (Rpar1 = Rpar2) but different window lengths (Rsense1 ≠ Rsense2), subtraction eliminates the parasitic resistance from the equation. This differential sensor design therefore should eliminate the parasitic resistance effects and give the maximum value of sensitivity.Figure 5


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)

Schematic illustration of the differential design and measurement configuration. Two sensors are used for the differential measurement, with long and short sensing windows. The sensors are otherwise identical.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig5: Schematic illustration of the differential design and measurement configuration. Two sensors are used for the differential measurement, with long and short sensing windows. The sensors are otherwise identical.
Mentions: To maximize the sensitivity, a differential biosensor design is proposed in Figure 5, which measures the difference in resistance between the two biosensors with different sensor window lengths. As the two biosensors have equal values of parasitic resistance (Rpar1 = Rpar2) but different window lengths (Rsense1 ≠ Rsense2), subtraction eliminates the parasitic resistance from the equation. This differential sensor design therefore should eliminate the parasitic resistance effects and give the maximum value of sensitivity.Figure 5

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.