Methods and apparatus for high throughput SEM and AFM for characterization of nanostructured surfaces
A system and method is provided for of characterizing nanostructured surfaces. A nanostructure sample is placed in an SEM chamber and imaged. The system and method locates one of the nanostructures using images from the SEM imaging, excises a top portion of the nanostructure, places said top portion on a substrate such that the nanostructures are perpendicular to the substrate and a base of the top portion contacts the substrate, performs high energy ion beam assisted deposition of metal at the base to attach the top portion to the substrate, SEM imaging the top portions in the SEM chamber, determining coordinates of the top portions relative to the substrate from the SEM imaging of the top portions, placing the substrate in an AFM chamber, and performing AFM imaging of the top portions using the coordinates previously determined.
1. A method of forming an overlay image, comprising
(a) providing an SEM image of a nanosensor sample including a plurality of vertically free standing nanostructures;
(b) AFM imaging a top portion of selected ones of the plurality of vertically standing nano structures;
(c) creating an overlaid image including an AFM imaged top portion overlayed on the SEM image.
2. The method of claim 1 , wherein prior to step (b), the method includes:
excising the top portions from the selected ones of the nanostructures and attaching the top portions to a substrate such that the nanostructures are perpendicular to the substrate and a base of the top portion contacts the substrate, and
SEM imaging the top portions, wherein the overlaid image includes the AFM imaged top portion overlayed on a corresponding SEM imaged top portion.
3. The method of claim 2 , wherein after step (c), the method includes
using the SEM image of the top portions to determine coordinates of the top portions relative to the substrate;
using the coordinates to overlay the AFM imaged top portion on the SEM imaged top portion to form the overlaid image.
4. The method of claim 2 , wherein, prior to excising the top portion, the method further comprises changing a spatial orientation of the sample in the SEM chamber until the top portion to be excised is a straight segment.
5. The method of claim 1 , further comprising determining nanostructure measurements and properties from the overlaid image.
6. The method of claim 1 , further comprising measuring roughness of a top of free standing nanostructures using the overlaid image.
7. The method of claim 2 , further comprising measuring adhesive forces between nanostructures and functional film from the overlaid image.
8. The method of claim 1 , further comprising measuring a size, shape and distribution of nanoparticles that form a functional coating on the nanostructures.
9. The method described in claim 2 , wherein the substrate is a conductive substrate, and the method further comprises
providing a potentiostat which applies a pre-determined voltage range and/or frequency range, wherein an AFM tip of the AFM is connected to one pole of the poteniostat and the conductive silicon substrate is connected to the other pole of the potentiostat;
providing a current measurement circuitry;
placing a skin graft/phantom with simulated sweat and optional metabolites in contact with the plurality of nanostructures on the conductive substrate;
measuring electrical conductivity distribution and electrochemical interactions on a surface of individual nanostructures while in contact with the skin graft/phantom.
10. The method of claim 2 , wherein the substrate is a conductive substrate, and the
method further comprises
providing a potentiostat which applies a pre-determined voltage range and/or frequency range, wherein an AFM tip of the AFM is connected to one pole of the poteniostat and the conductive silicon substrate is connected to the other pole of the potentiostat;
providing a current measurement circuitry;
submerging the nanostructures on the conductive substrate and AFM tip in a liquid medium;
measuring electrochemical interactions to analyze chemical interaction between nanostructured fiber surface and the liquid medium.
11. The method of claim 1 , wherein each of the plurality of nanostructures include a nanometer scale pillar on a micrometer scale stock.
12. The method of claim 2 , wherein the excising is performed with a focused high energy electron/ion beam.
13. A method of forming an overlay image, comprising
(a) providing a nanosensor sample including a plurality of vertically free standing nano structures;
(b) excising a top portion of selected ones of the plurality of nanostructures,
(c) attaching said top portions to a substrate such that the vertically standing nanostructures are perpendicular to the substrate and a base of the top portions contact the substrate,
(d) SEM imaging the top portions;
(e) determining coordinates of the top portions relative to the substrate from the SEM imaging of the top portions,
(f) placing the substrate in an AFM chamber, and
(g) AFM imaging the top portions using the coordinates previously determined;
(h) creating an overlaid image including the AFM image of one of the top portions overlayed on the SEM image of said one of the top portions.