Improved Hydrolytic Stability and Repeatability: pH sensing with APTES-coated silicon nanowire bio-FETs
IEEE Nanotechnology Magazine
T This arTicle addresses The hydrolytic instability issue of surface chemistry and the repeatability issue of silicon (si) nanowire (NW) biosensors. si multi-NWs or nanograting (NG) field-effect transistors (FeTs) were fabricated using semiconductor lithographic processing techniques. Then, the NG surfaces were coated with 3-aminopropyltriethoxysilane (aPTes) via the vapor-and solution-phase methods. Their performance, including drift, stability, sensitivity, accuracy, and linearity of ph
... nearity of ph sensing, was evaluated. sensors treated with both aPTes deposition methods exhibit linear ph response with good sensitivity. devices treated with vapor aPTes show better linearity and sensitivity, and aPTes-solution-coated devices are more stable with smaller drift. a hydrolysis process was developed to significantly improve the hydrolytic stability of the aPTes-coated sensor surface. as a result, an accuracy of ±0.008 ph was achieved, which is comparable to or better than commercially available ion-sensitive FeTs (isFeTs), whereas the sensor drift was significantly reduced for both sensors treated with vapor and solution aPTes. This hydrolysis process has greatly improved the stability and repeatability of charge sensing of our si NG bio-FeTs. driven by the improvement in nanostructure fabrication and characterization technologies, nanoelectronic biosensors have received much attention as a promising approach to detect biological and chemical species, with a variety of applications in disease diagnosis, drug discovery, food safety, etc. -. in particular, si NW FeTs have demonstrated potential as a highly sensitive, label-free sensing platform , , -. advantages include high sensitivity attributed to the large surface-to-volume ratio and the resulting strong modulation of carrier concentration by the surface charges , , as well as facility for mass production due to the compatibility with current complementary metal-oxide semiconductor fabrication technologies , , , .