Silicon nanowire biosensor and its applications in disease diagnostics: A review

Silicon nanowire (SiNW) sensors have been developed by using top-down fabrication that is CMOS (complementary metal‐oxide‐semiconductor) compatible for resistive chemical detection with fast response and high sensitivity. Top-down fabrication by electron beam lithography and reactive ion etching of a silicon on insulator (SOI) substrate enables compatibility with the CMOS fabrication process, accurate alignment with other electrical components, flexible design of the nanowire geometry and good control of the electrical characteristics. The SiNW sensors showed a large operation range for pH detection (pH = 4‐10) with an average sensitivity of (� R/R)/pH = 2.6%/pH and a rise time of 8 s. A small pH level difference (� pH = 0.2) near neutral pH conditions (pH = 7) could be resolved with the SiNW sensors. The sensor response to the presence of alkali metal ions and the long term drifting effects were also investigated. (Some figures in this article are in colour only in the electronic version)

https://iopscience.iop.org/article/10.1088/0957-4484/21/1/015501/pdf

Top-down fabricated silicon nanowire sensors for real-time chemical detection

Nanowire sensors for multiplexed detection of biomolecules.

Recent studies have demonstrated the ability of semiconducting nanowire (NW) field-effect transistors (FETs) to serve as highly sensitive label-free sensors for biochemicals, including small molecules, proteins, and nucleic acids. The nanoscale confinement of the channel current in concert with the large-surface area-to-volume ratio enables charged molecules bound to the surface to effectively gate the device. Functionalization of the NW surface with specific receptors therefore enables direct electronic detection of particular molecules of interest. The original work in the field relied on NWs grown by the chemical vapor deposition method, which require hybrid bottom-up fabrication processes for device realization. The lack of reproducibility with these techniques and the associated inability to leverage the central advantage of complementary MOSFETs, namely, very large scale integration, have recently led a number of groups to create NW sensors using only traditional top-down fabrication techniques. In this paper, we focus primarily on these most recent studies and discuss necessary future studies as dictated by experimental and theoretical considerations.

Semiconducting Nanowire Field-Effect Transistor Biomolecular Sensors

https://ir.nctu.edu.tw:443/bitstream/11536/24597/1/000337863900014.pdf

Silicon nanowire field-effect-transistor based biosensors: from sensitive to ultra-sensitive.

In this letter, we report a novel approach to selectively functionalize the surface of silicon nanowires located on silicon-based substrates. This method is based upon highly localized nanoscale Joule heating along silicon nanowires under an applied electrical bias. Numerical simulation shows that a high-temperature (>800 K) with a large thermal gradient can be achieved by applying an appropriate electrical bias across silicon nanowires. This localized heating effect can be utilized to selectively ablate a protective polymer layer from a region of the chosen silicon nanowire. The exposed surface, with proper postprocessing, becomes available for surface functionalization with chemical linker molecules, such as 3-mercaptopropyltrimethoxysilanes, while the surrounding area is still protected by the chemically inert polymer layer. This approach is successfully demonstrated on silicon nanowire arrays fabricated on SOI wafers and visualized by selective attachment of gold nanoparticles.

and Albert P. Pisano

Papers

Selective surface functionalization of silicon nanowires via nanoscale joule heating