Chemical sensing and/or measuring devices and methods
Methods for fabricating silicon nanowire chemical sensing devices, devices thus obtained, and methods for utilizing devices for sensing and measuring chemical concentration of selected species in a fluid are described. Devices may comprise a metal-oxide-semiconductor field-effect transistor (MOSFET) structure.
1. A device comprising:
a semiconductor substrate with a planar surface;
a semiconductor nanopillar on the semiconductor substrate and substantially perpendicular to the planar surface;
an insulating layer covering the semiconductor nanopillar;
a conductive layer covering the insulating layer, wherein all space between the conductive layer and the semiconductor nanopillar is completely filled by the insulating layer, wherein the conductive layer and the insulating layer are devoid of an end portion thereof, thus exposing an uninsulated pillar end of the semiconductor nanopillar; and
a functional layer covering the conductive layer, wherein an insulating layer end of the insulating layer protrudes beyond a conductive layer end and terminates before the uninsulated pillar end of the semiconductor nanopillar,
wherein the functional layer is a bilayer, the bilayer comprising:
an attractive layer for attracting a selected type of chemical species; and
a semi-permeable insulating layer, the semi-permeable insulating layer being on the attractive layer, wherein the semi-permeable insulating layer is configured to allow the selected type of chemical species to pass through and to insulate the attractive layer and the conductive layer of the device.
2. The device of claim 1 , wherein the uninsulated pillar end forms an electrically contactable terminal and the functional layer forms a chemically contactable terminal.
3. The device of claim 1 , wherein the functional layer is configured to attract a selected type of chemical species.
4. The device of claim 1 , wherein the functional layer is configured to attract ions.
5. The device of claim 1 , wherein the semiconductor nanopillar and the semiconductor substrate are made of silicon.
6. The device of claim 1 , further comprising a conductive backside terminal coated on a backside of the semiconductor substrate, opposite the semiconductor nanopillar.
7. The device of claim 6 , the device being a metal-oxide-semiconductor field-effect transistor (MOSFET) structure.
8. The device of claim 7 , the conductive layer being a gate terminal of the MOSFET.
9. A microfluidic channel structure comprising one or more devices according to claim 1 .
10. The device of claim 1 , wherein the semiconductor nanopillar is a plurality of semiconductor nanopillars.
11. The device of claim 8 , wherein the semiconductor substrate is a source or a drain of the MOSFET and the uninsulated pillar end is respectively the drain or the source of the MOSFET.
12. The device of claim 1 , wherein the attractive layer contains gold.
13. The device of claim 1 , wherein the functional layer is an insulating semi-permeable matrix with domain of gold within.