Editing Nanotechnology (section)

==Tools and techniques==
[[File:AFMsetup.jpg|thumb|right|upright=1.35|Typical [[atomic force microscopy|AFM]] setup. A microfabricated [[cantilever]] with a sharp tip is deflected by features on a sample surface, much like in a [[phonograph]] but on a much smaller scale. A [[laser]] beam reflects off the backside of the cantilever into a set of [[photodetector]]s, allowing the deflection to be measured and assembled into an image of the surface.]]

===Scanning microscopes===
The [[atomic force microscopy|atomic force microscope]] (AFM) and the [[Scanning Tunneling Microscope]] (STM) are two versions of scanning probes that are used for nano-scale observation. Other types of [[scanning probe microscopy]] have much higher resolution, since they are not limited by the wavelengths of sound or light.

The tip of a scanning probe can also be used to manipulate nanostructures (positional assembly). [[Feature-oriented scanning]] may be a promising way to implement these nano-scale manipulations via an automatic [[algorithm]].<ref name="feature2004">{{cite journal| vauthors = Lapshin RV |year=2004|title=Feature-oriented scanning methodology for probe microscopy and nanotechnology|journal=Nanotechnology|volume=15|issue=9|pages=1135–51|doi=10.1088/0957-4484/15/9/006|url=http://www.lapshin.fast-page.org/publications.htm#feature2004|format=PDF|bibcode=2004Nanot..15.1135L|s2cid=250913438|url-status=live|archive-url=https://web.archive.org/web/20130909230837/http://www.lapshin.fast-page.org/publications.htm#feature2004|archive-date=2013-09-09}}</ref><ref name="fospm2011">{{cite book| vauthors = Lapshin RV |year=2011|contribution=Feature-oriented scanning probe microscopy|title=Encyclopedia of Nanoscience and Nanotechnology| veditors = Nalwa HS |volume=14|pages=105–115|publisher=American Scientific |isbn=978-1-58883-163-7|url=http://www.lapshin.fast-page.org/publications.htm#fospm2011|format=PDF|url-status=live|archive-url=https://web.archive.org/web/20130909230837/http://www.lapshin.fast-page.org/publications.htm#fospm2011|archive-date=2013-09-09}}</ref> However, this is still a slow process because of low velocity of the microscope.

The top-down approach anticipates nanodevices that must be built piece by piece in stages, much as manufactured items are made. [[Scanning probe microscopy]] is an important technique both for characterization and synthesis. Atomic force microscopes and scanning tunneling microscopes can be used to look at surfaces and to move atoms around. By designing different tips for these microscopes, they can be used for carving out structures on surfaces and to help guide self-assembling structures. By using, for example, feature-oriented scanning approach, atoms or molecules can be moved around on a surface with scanning probe microscopy techniques.<ref name="feature2004" /><ref name="fospm2011" />

===Lithography===
Various techniques of lithography, such as [[optical lithography]], [[X-ray lithography]], dip pen lithography, [[electron beam lithography]] or [[nanoimprint lithography]] offer top-down fabrication techniques where a bulk material is reduced to a nano-scale pattern.

Another group of nano-technological techniques include those used for fabrication of [[Ion track technology (track etching)|nanotubes]] and [[Ion track technology (track replication)|nanowires]], those used in semiconductor fabrication such as deep ultraviolet lithography, electron beam lithography, focused ion beam machining, nanoimprint lithography, [[atomic layer deposition]], and [[molecular vapor deposition]], and further including molecular self-assembly techniques such as those employing di-block [[copolymer]]s.<ref name="pmid26295171">{{cite journal | vauthors = Kafshgari MH, Voelcker NH, Harding FJ | title = Applications of zero-valent silicon nanostructures in biomedicine | journal = Nanomedicine | volume = 10 | issue = 16 | pages = 2553–71 | year = 2015 | pmid = 26295171 | doi = 10.2217/nnm.15.91 }}</ref>

====Bottom-up====
In contrast, bottom-up techniques build or grow larger structures atom by atom or molecule by molecule. These techniques include chemical synthesis, [[self-assembly]] and positional assembly. [[Dual-polarization interferometry]] is one tool suitable for characterization of self-assembled thin films. Another variation of the bottom-up approach is [[molecular-beam epitaxy]] or MBE. Researchers at [[Bell Telephone Laboratories]] including [[John R. Arthur Jr.|John R. Arthur]]. [[Alfred Y. Cho]], and Art C. Gossard developed and implemented MBE as a research tool in the late 1960s and 1970s. Samples made by MBE were key to the discovery of the [[fractional quantum Hall effect]] for which the [[List of Nobel laureates in Physics|1998 Nobel Prize in Physics]] was awarded. MBE lays down atomically precise layers of atoms and, in the process, build up complex structures. Important for research on semiconductors, MBE is also widely used to make samples and devices for the newly emerging field of [[spintronics]].

Therapeutic products based on responsive [[nanomaterials]], such as the highly deformable, stress-sensitive [[Transfersome]] vesicles, are approved for human use in some countries.<ref>{{cite journal | vauthors = Rajan R, Jose S, Mukund VP, Vasudevan DT | title = Transferosomes - A vesicular transdermal delivery system for enhanced drug permeation | journal = Journal of Advanced Pharmaceutical Technology & Research | volume = 2 | issue = 3 | pages = 138–143 | date = July 2011 | pmid = 22171309 | pmc = 3217704 | doi = 10.4103/2231-4040.85524 | doi-access = free }}</ref>