Thermochemical nanolithography (TCNL) or thermochemical scanning probe lithography (tc-SPL) is a

scanning probe microscopy Scanning probe microscopy (SPM) is a branch of microscopy that forms images of surfaces using a physical probe that scans the specimen. SPM was founded in 1981, with the invention of the scanning tunneling microscope, an instrument for imaging ...

-based

nanolithography Nanolithography (NL) is a growing field of techniques within nanotechnology dealing with the engineering (patterning e.g. etching, depositing, writing, printing etc) of Nanometre, nanometer-scale structures on various materials. The modern term r ...

technique which triggers thermally activated

chemical reaction A chemical reaction is a process that leads to the chemistry, chemical transformation of one set of chemical substances to another. When chemical reactions occur, the atoms are rearranged and the reaction is accompanied by an Gibbs free energy, ...

s to change the chemical functionality or the

phase Phase or phases may refer to: Science *State of matter, or phase, one of the distinct forms in which matter can exist *Phase (matter), a region of space throughout which all physical properties are essentially uniform *Phase space, a mathematica ...

surfaces A surface, as the term is most generally used, is the outermost or uppermost layer of a physical object or space. Surface or surfaces may also refer to: Mathematics *Surface (mathematics), a generalization of a plane which needs not be flat * Sur ...

. Chemical changes can be written very quickly through rapid probe scanning, since no mass is transferred from the tip to the surface, and writing speed is limited only by the heat transfer rate. TCNL was invented in 2007 by a group at the Georgia Institute of Technology. Riedo and collaborators demonstrated that TCNL can produce local chemical changes with feature sizes down to 12 nm at scan speeds up to 1 mm/s. TCNL was used in 2013 to create a nano-scale replica of the

Mona Lisa The ''Mona Lisa'' is a half-length portrait painting by the Italian artist Leonardo da Vinci. Considered an archetypal masterpiece of the Italian Renaissance, it has been described as "the best known, the most visited, the most written about, ...

"painted" with different probe tip temperatures. Called the ''

Mini Lisa The ''Mini Lisa'' is a nanoscale replica of the ''Mona Lisa''. It was created in 2013 by Keith Carroll, a Georgia Institute of Technology PhD candidate, in order to demonstrate a technique called thermochemical nanolithography (TCNL) that was i ...

'', the portrait measured , about 1/25,000th the size of the original.

Technique

The AFM thermal cantilevers are generally made from a silicon wafers using traditional bulk and

surface A surface, as the term is most generally used, is the outermost or uppermost layer of a physical object or space. It is the portion or region of the object that can first be perceived by an observer using the senses of sight and touch, and is ...

micro-machining processes. Through the application of an electric

current Currents, Current or The Current may refer to: Science and technology * Current (fluid), the flow of a liquid or a gas ** Air current, a flow of air ** Ocean current, a current in the ocean *** Rip current, a kind of water current ** Current (hydr ...

through its highly doped

silicon Silicon is a chemical element; it has symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic lustre, and is a tetravalent metalloid (sometimes considered a non-metal) and semiconductor. It is a membe ...

wings,

resistive heating Joule heating (also known as resistive heating, resistance heating, or Ohmic heating) is the process by which the passage of an electric current through a conductor produces heat. Joule's first law (also just Joule's law), also known in countr ...

occurs at the light doping zone around the probe tip, where the largest fraction of the heat is dissipated. The tip is able to change its temperature very quickly due to its small volume; an average tip in contact with

polycarbonate Polycarbonates (PC) are a group of thermoplastic polymers containing carbonate ester, carbonate groups in their chemical structures. Polycarbonates used in engineering are strong, toughness, tough materials, and some grades are optically transp ...

has a time constant of 0.35 ms. The tips can be cycled between ambient temperature and 1100 °C at up to 10 MHz while the distance of the tip from the surface and the tip temperature can be controlled independently.

Applications

Thermally activated reactions have been triggered in

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

organic semiconductor Organic semiconductors are solids whose building blocks are pi-bonded molecules or polymers made up by carbon and hydrogen atoms and – at times – heteroatoms such as nitrogen, sulfur and oxygen. They exist in the form of molecular crystals o ...

electroluminescent Electroluminescence (EL) is an optical and electrical phenomenon, in which a material emits light in response to the passage of an electric current or to a strong electric field. This is distinct from black body light emission resulting from ...

conjugated polymers, and

nanoribbon Nanoribbon may refer to: * Graphene nanoribbons * Silicene nanoribbons * Boron nitride nanoribbons * Gallium(III) oxide nanoribbons * titanate nanoribbons - see titanium dioxide Titanium dioxide, also known as titanium(IV) oxide or titania ...

resistors.

Deprotection A protecting group or protective group is introduced into a molecule by chemical modification of a functional group to obtain chemoselectivity in a subsequent chemical reaction. It plays an important role in multistep organic synthesis. In man ...

functional group In organic chemistry, a functional group is any substituent or moiety (chemistry), moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions r ...

s (sometimes involving a

temperature gradient A temperature gradient is a physical quantity that describes in which direction and at what rate the temperature changes the most rapidly around a particular location. The temperature spatial gradient is a vector quantity with Dimensional analysis, ...

s), and the reduction of graphene oxide has been demonstrated. The

wettability Wetting is the ability of a liquid to displace gas to maintain contact with a solid surface, resulting from intermolecular interactions when the two are brought together. These interactions occur in the presence of either a gaseous phase or an ...

of a

polymer A polymer () is a chemical substance, substance or material that consists of very large molecules, or macromolecules, that are constituted by many repeat unit, repeating subunits derived from one or more species of monomers. Due to their br ...

surface at the nanoscale has been modified, and nanostructures of

poly(p-phenylene vinylene) Poly(''p''-phenylene vinylene) (PPV, or polyphenylene vinylene) is a Conducting polymers, conducting polymer of the rigid-rod polymer family. PPV is the only polymer of this type that can be processed into a highly ordered crystalline thin film. ...

(an

electroluminescence Electroluminescence (EL) is an optical phenomenon, optical and electrical phenomenon, in which a material emits light in response to the passage of an electric current or to a strong electric field. This is distinct from black body light emission ...

conjugated polymer) have been created. Nanoscale templates on polymer films for the assembly of nano-objects such as

s and

DNA Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...

have also been created and

crystallization Crystallization is a process that leads to solids with highly organized Atom, atoms or Molecule, molecules, i.e. a crystal. The ordered nature of a crystalline solid can be contrasted with amorphous solids in which atoms or molecules lack regu ...

of ferroelectric

ceramics A ceramic is any of the various hard, brittle, heat-resistant, and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porce ...

with storage densities up to 213 Gb/in² have been produced. The use of a material that can undergo multiple chemical reactions at significantly different temperatures could lead to a multi-state system, wherein different functionalities can be addressed at different temperatures. Synthetic polymers, such as PMCC, have been used as functional layers on substrate, which allow for high-resolution patterning.{{Cite journal , last1=Albisetti , first1=E , last2=Carroll , first2=K M , last3=Lu , first3=X , last4=Curtis , first4=J E , last5=Petti , first5=D , last6=Bertacco , first6=R , last7=Riedo , first7=E , date=2016-06-27 , title=Thermochemical scanning probe lithography of protein gradients at the nanoscale , url=http://dx.doi.org/10.1088/0957-4484/27/31/315302 , journal=Nanotechnology , volume=27 , issue=31 , pages=315302 , doi=10.1088/0957-4484/27/31/315302 , pmid=27344982 , bibcode=2016Nanot..27E5302A , hdl=11311/1004178 , issn=0957-4484, hdl-access=free

Comparison with other lithographic techniques

''Thermo-mechanical'' scanning probe lithography relies on the application of heat and force order to create indentations for patterning purposes (see also:

Millipede memory Millipede memory is a form of non-volatile computer memory. It promised a data density of more than 1 terabit per square inch (1 gigabit per square millimeter), which is about the limit of the perpendicular recording hard drives. Millipede st ...

). ''Thermal scanning probe lithography'' (t-SPL) specializes on removing material from a substrate without the intent of chemically altering the created topography.

Local oxidation nanolithography Local oxidation nanolithography (LON) is a tip-based nanofabrication method. It is based on the spatial confinement on an oxidation reaction under the sharp tip of an atomic force microscope. The first materials on which LON was demonstrated were ...

relies on oxidation reactions in a water meniscus around the probe tip.

References

External links

picoForce Laboratory at the Georgia Institute of Technology
* http://www.picoforcelab.org/thermochemical-nanolithography-tcnl Nanotechnology

Technique

Applications

Comparison with other lithographic techniques

See also

References

External links