WO2014133530A1 - Trajectoires de mécanosynthèse - Google Patents

Trajectoires de mécanosynthèse Download PDF

Info

Publication number
WO2014133530A1
WO2014133530A1 PCT/US2013/028415 US2013028415W WO2014133530A1 WO 2014133530 A1 WO2014133530 A1 WO 2014133530A1 US 2013028415 W US2013028415 W US 2013028415W WO 2014133530 A1 WO2014133530 A1 WO 2014133530A1
Authority
WO
WIPO (PCT)
Prior art keywords
tool
tip
hydrogen
reaction
atom
Prior art date
Application number
PCT/US2013/028415
Other languages
English (en)
Inventor
Robert A. FREITAS, Jr.
Ralph C. Merkle
Original Assignee
Freitas Robert A Jr
Merkle Ralph C
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Freitas Robert A Jr, Merkle Ralph C filed Critical Freitas Robert A Jr
Priority to PCT/US2013/028415 priority Critical patent/WO2014133530A1/fr
Publication of WO2014133530A1 publication Critical patent/WO2014133530A1/fr

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82B—NANOSTRUCTURES FORMED BY MANIPULATION OF INDIVIDUAL ATOMS, MOLECULES, OR LIMITED COLLECTIONS OF ATOMS OR MOLECULES AS DISCRETE UNITS; MANUFACTURE OR TREATMENT THEREOF
    • B82B3/00—Manufacture or treatment of nanostructures by manipulation of individual atoms or molecules, or limited collections of atoms or molecules as discrete units
    • B82B3/0009—Forming specific nanostructures
    • B82B3/0019—Forming specific nanostructures without movable or flexible elements

Definitions

  • the present application relates to mechanosynthesis, the fabrication of atomically precise tools and materials using individual atoms or small groups of atoms as the fundamental building blocks, and more particularly, to devices, methods and systems for performing ordered sequences of site-specific positionally controlled chemical reactions that are induced by use of mechanical force.
  • MEMS micro-electromechanical systems
  • NEMS nano-electromechanical systems
  • MEMS and NEMS technologies are used to create devices as diverse as airbags and cell phones (e.g., accelerometers and attitude sensing), projection screens (e.g., digital light projection), and medical diagnostics (e.g., lab-on-a-chip devices).
  • Mechanosynthesis offers the ability to create atomically-precise structures out of a wide variety of atoms or molecules, while being relatively unconstrained in the shapes and properties of the devices which can be built. This offers great benefit to numerous industries not only because it allows the construction of parts and devices which cannot be manufactured through other means, but even with respect to bulk materials which can be manufactured through other means, the materials manufactured via mechanosynthesis, due to their atomic precision, can have properties superior to the same materials manufactured by conventional means.
  • Mechanosynthesis and Mechanosynthesis Terminology The present invention describes methods, systems and products relating to the manufacture of atomically-precise structures using atoms as raw material. These atoms are referred to as feedstock.
  • the structures are referred to as workpieces.
  • Workpieces are built using positionally-controlled tips, such as the tips on Atomic Force Microscopes, to move feedstock atoms into desired locations on a workpiece. Mechanical force is applied to atoms via these tips to make and break chemical bonds. This mechanical making or breaking of bonds at specific locations is called mechanosynthesis.
  • a build sequence also encompasses the concept of a trajectory, which is the path along which an atom moves during a
  • Tips Used in Mechanosynthesis use a variety of ultra-sharp tips designed to move atoms with sub-angstrom precision and to facilitate different reactions with those atoms.
  • the tips may be, but do not have to be, atomically-precise. While some embodiments of the invention use atomically-precise tips, others do not.
  • a bootstrap sequence is presented herein which allows the creation of atomically-precise tips using non-atomically-precise tips.
  • Atomically imprecise, but ultra-sharp tips also called probes, are available commercially (e.g., from Nanotools Gmbh, Kunststoff, Germany, or from NANOSENSORS, Neuchatel, Switzerland), or can be made using electron-beam induced deposition (EBID), among others techniques.
  • EBID electron-beam induced deposition
  • Such tips can serve as a starting point for the bootstrap process described herein.
  • the important characteristic of a tip is that it reliably performs the desired mechanosynthetic reaction.
  • Atomic precision is a helpful characteristic of tips for mechanosynthesis because knowing the precise placement of atoms on the tip allows design of reliable reactions via computational chemistry simulations. This is not to say that atomically imprecise tips could not be used in sophisticated mechanosynthesis processes (as the bootstrap process discussed herein demonstrates), for example, by characterizing each tip before use, by designing reactions where variation at the tip does not substantially affect the intended reactions, or by designing procedures which result in minimal variation when preparing tips.
  • tips and "workpieces” are discussed extensively herein. However, while these terms are used for clarity, defining one structure as the tip and another as the workpiece can be arbitrary in certain circumstances.
  • a tip removes a hydrogen atom from a workpiece
  • the workpiece donated a hydrogen atom to the tip, logically reversing their roles.
  • This distinction may seem pedantic, but is of more than academic importance during mechanosynthetic processes such as tip refresh or using one set of tips to build another. In such instances, because you are adding or removing atoms from the tip to refresh it for the next reaction, or because you are building new tips, the tip could be considered the workpiece.
  • the ability to perform robust mechanosynthesis requires that one be able to position atoms (generally with sub-angstrom precision), that one be able to apply mechanical force to an atom in a specific direction to cause the making or breaking of bonds, that one be able to define a desired workpiece (or at least certain regions of the workpiece) with atomic precision, that one be able to calculate trajectories which will result in successful
  • mechanosynthetic reactions and that one possess, or be able to design, tips to carry out the intended reactions.
  • AFM/SPM/STM Microscopy By 2006, sub-angstrom positioning in three dimensions was available for SPM. For comparison purposes, the diameter of a carbon atom is 1.54 angstroms, meaning that SPM tips could be reliably positioned to substantially less than the diameter of an atom. Also by 2006, such microscopy could be performed in ultrahigh vacuum and at cryogenic temperatures, and "Vibration and drift have been controlled such that a probe tip can be held over a single molecule for hours of observation.” Bharat Bhushan (Ed.) (2006) Springer Handbook of Nano-technology, Springer.
  • Element Grouping and Simulation When referring to groups of elements herein, we may talk about metals, non-metals, noble gases (which we consider largely unsuited to participating directly in mechanosynthetic reactions due to their unreactive nature), transuranic elements (which we consider difficult to simulate using current software tools and hardware capabilities due to their complex electronic structure and/or lack of basis sets), stable elements (which are defined as non-radioactive isotopes and isotopes with half- lives long enough to support manufacturing and use of a product), or other logical groupings.
  • Feedstock and Presentation Surfaces Mechanosynthesis requires a source of atoms on which to perform reactions. These atoms are referred to as feedstock, and to the location at which these atoms are stored as the feedstock depot. Feedstock generally resides on a presentation surface although other ways of supplying feedstock are feasible, such as liquid, gas, or as bulk solids rather than just a surface layer. Feedstock could also come attached to a tip and the tip disposed of after use.
  • a tip under positional control can be brought to the feedstock depot and bonded to feedstock, allowing the tip to remove the feedstock from the feedstock depot and carry it away to participate in mechanosynthetic operations, e.g., to add one or more atoms to a specific site on a workpiece.
  • a presentation surface may provide more than one type of feedstock.
  • Different feedstock could be arranged in a monolayer in different sectors of the presentation surface, or, with techniques like ALCVD, could be layered on top of each other.
  • the feedstock could also be the surface itself.
  • the range of elements and compounds that can be deposited on surfaces, part of the surface itself, or created through reactions resulting in adsorbed species includes Al, BN, BeO, CH4, GaAs, Ir, LiMn04, Mo, Ni, P205, Pt, Ru, Si, Si3N4, Si02, Sn02, Ti, Ta, W, ZnO, ZnS, ZnSE, and ZnTe, among others.
  • feedstock could be bonded to a presentation surface in either manner.
  • a surface that chemisorbs one type of feedstock may physically adsorb another, although there are surfaces that tend to allow primarily physical adsorption, such as a frozen noble gas.
  • Frozen noble gases are used both as a surface and a matrix (that is, throughout its bulk) for trapping small molecules, and are not the only set of fairly unreactive gases or compounds (for example, SiF4 may serve in a similar capacity, as might fluorinated polymers).
  • Covalent bonding may also be useful at higher temperatures that would permit migration or desorption of physically adsorbed feedstock.
  • Reliability is an important consideration in the design of reaction sequences for multi-atom workpieces. While some imperfections in a workpiece may be tolerable, all other things being equal, the higher the number of atoms in the workpiece, the greater the need for reliability. Reaction reliability can be achieved in a variety of ways, including use of reactions with energy barriers sufficient to prevent spontaneous reactions at a given temperature, reactions designed to avoid pathological side reactions, or the introduction of a testing step during mechanosynthesis. These topics are discussed in more detail below.
  • Reliability may also be determined via simulations incorporating realistic or actual equipment limitations. For example, if the positional means have known error bounds or distributions, these could be taken into account via Monte Carlo simulations.
  • reaction barriers or energy deltas are often overcome by thermal energy.
  • thermal energy is nonspecific and facilitates desired and undesired reactions alike. Reducing temperature decreases the thermal energy available to cause non-specific reactions. This reduces the likelihood of pathological side reactions while directed mechanical force, even at low temperatures, still facilitates desired reactions.
  • testing The most basic mechanosynthesis process involves performing a reaction with the assumption that the desired reaction took place as expected. This may be a reasonable assumption since reactions can be engineered to have high degrees of reliability. However, it is possible to obtain information on what reaction actually occurred. For example, AFM or STM techniques can be used to scan the workpiece after a reaction. If an undesired reaction occurred, various actions can be taken such as simply noting the error if it is not critical to the workpiece function, fixing the error, or discarding the workpiece and starting over.
  • US Patent #7,687,146 teaches a dimer tip for mechanosynthetic fabrication.
  • the invention is described as comprising "adamantane molecules arranged in a polymantane or lonsdaleite configuration" and a "dimerholder atom.”
  • the tip structure is thus constrained to a very specific set of structures and is directed to the use of a dimer as feedstock.
  • the tip is intended for use with deposition surfaces "having a melting point of at least 300° C, a thermal expansion coefficient maximally different than that of diamond, a mismatch in crystal lattice constant as compared to that of diamond, resistance to carbide formation, less bonding strength to the carbon dimer as compared to bonding strength between the diamondholder atom X and the carbon dimer, and little or no solubility or reaction with carbon.”
  • deposition surfaces having a melting point of at least 300° C, a thermal expansion coefficient maximally different than that of diamond, a mismatch in crystal lattice constant as compared to that of diamond, resistance to carbide formation, less bonding strength to the carbon dimer as compared to bonding strength between the diamondholder atom X and the carbon dimer, and little or no solubility or reaction with carbon.
  • Prior Art is Surface-Based.
  • mechanosynthesis is generally performed on, or to, a surface. For example, in Oyabu, Custance et al. (2003) and Oyabu, Custance et al. (2004), vertical manipulation of single atoms was performed, on either a Si or Ge surface.
  • Prior Art Uses Presentation Surface as Feedstock and Workpiece.
  • the prior art frequently uses the presentation surface itself as what we refer to as the feedstock depot, the feedstock, and the workpiece. For example, atoms are removed from the crystal structure of the presentation surface and then added back to a void in that same presentation surface. The atoms are not being removed from the surface to transport to a workpiece distinct from the presentation surface.
  • the presentation surface is the source of the feedstock and it is also the workpiece which is being altered by the mechanosynthetic reactions.
  • Use of the presentation surface as the feedstock depot, feedstock, and workpiece places limitations on what workpieces may be built, as workpieces are thus limited to being made out of the same element(s) as the presentation surface, among other drawbacks.
  • Prior Art Limited to One or Two Dimensions The prior art does not anticipate being able to extend atomically-precise mechanosynthetically-created structures into three dimensions. Creating a three-dimensional structure using mechanosynthesis is not simply the extension or repetition of a two-dimensional motif. The bonding structure and build sequence must support extension into the third dimension through a sequence of reactions that is chemically and geometrically feasible without pathological rearrangement of intermediate products. This requires a considered build sequence resulting from analysis of the reactions and intermediate structures, and such strategies are not taught in the prior art. [0050] Prior Art Teaches Limited Reactions and Elements.
  • the prior art is frequently limited to the removal of a single adatom (a surface atom), or the insertion of a single atom into a vacancy left by the removal of such an adatom, often using a single element and involving a very specific crystal structure.
  • a single adatom a surface atom
  • Oyabu, Custance et al. (2003) andOyabu, Custance et al. (2004) use either all Si atoms, or all Ge atoms, respectively. There is no evidence that different intentional modifications to the presentation surface could have been made or that different crystallographic faces could have been used.
  • Prior Art Does Not Use Atomically-Precise Tips.
  • the prior art generally does not use atomically-precise tips (US Patent #7,687,146 is one exception that is discussed in detail herein).
  • the tip in Oyabu, Custance et al. (2003) is described as a "Si tip apex [that] was carefully cleaned up by argon-ion bombardment for 30 min.” Such a process would result in a tip where the placement of individual atoms was unknown.
  • a tip is not atomically-precise its reaction characteristics cannot be exactly defined via computational chemistry modeling, and would not be the same from tip to tip.
  • Prior Art Does Not Teach Varied Tips. When contemplating numerous reactions between various elements, different tips will be required to facilitate the specific reactions desired. To the best of our knowledge the prior art does not address this issue.
  • Prior Art Does Not Provide For Specific Levels of Reaction Accuracy. The accuracy of the mechanosynthetic reactions must be considered if one is to build workpieces with a known level of confidence. The mechanosynthesis prior art generally does not address the issue of designing for reaction reliability. Some prior art reports the reliability of a given reaction after the fact based on experimental results, but this is very different than
  • the prior art generally uses atomically-imprecise tips. Even where modeling is performed in the prior art, modeling of an atomically-imprecise tip is unlikely to accurately represent the actual experimental system due to lack of knowledge of the exact structure of the tip. Obviously, since the prior art is not directed to a system with a planned level of reliability, neither does the prior art investigate reaction reliability across a range of tips, elements, or conditions to teach a generalizable system.
  • Prior Art Using Voltage Biases contains examples of atomic- scale synthesis using voltage biases. Voltage biases can be used to modify surface bonding patterns by two general mechanisms: localized heating and electrostatic fields. Such mechanisms may be less specific than mechanosynthesis in their ability to facilitate reliable reactions, but provide easily-accessible ways to make and break covalent bonds. While it should be noted that mechanosynthesis and voltage-based techniques could be combined, no generalizable system using voltages has been taught in the prior art and in general, the same advantages that distinguish the present invention from the mechanosynthesis prior art also distinguish the present invention from the voltage-based prior art. [0058] Prior Art Not Using Individual Atoms or Molecules. Prior art using large
  • presentation surface also frequently serves as the feedstock depot, feedstock and workpiece, such as with the "vertical manipulation" prior art, of which Oyabu, Custance et al. (2003) andOyabu, Custance et al. (2004) are representative. Without separating the presentation surface, feedstock and workpiece, the ability to create diverse structures can be limited.
  • the present invention is directed to tools, systems and methods that perform mechanosynthesis in a manner allowing the creation of workpieces from a wide variety of elements, using diverse reactions of known reliability, even when requiring many atoms or when the workpiece is three dimensional.
  • Mechanosynthesis trajectories are described which are approximately coaxial, and are shown to be useful in a wide range of mechanosynthesis reactions regardless of the nature of the tip or the feedstock being transferred.
  • FIG. 1 A is an active Hydrogen Abstraction Tool
  • FIG. IB is a spent Hydrogen Abstraction Tool
  • FIG. 2 is a Hydrogen Donation Tool
  • FIG. 3 is a Germanium Radical Tool
  • FIG. 4 is a Methylene Tool
  • FIG. 5 is a GermylMethylene Tool
  • FIG. 6 is a Germylene Tool
  • FIG. 7 is a Hydrogen Transfer Tool
  • FIG. 8 is an Adamantane Radical Tool
  • FIG. 9 is a Dimer Placement Tool
  • FIG. 10A shows a Hydrogen Abstraction Tool selectively abstracting a
  • FIG. 10B shows abstraction in the transfer of a hydrogen atom and conversion to a spent Hydrogen Abstraction Tool
  • FIG. 11 A shows a Hydrogen Donation Tool selectively donating a hydrogen atom
  • FIG. 1 IB shows the donation of a hydrogen atom and conversion to a
  • FIG. 12A shows a Germanium Radical Tool bonding to a spent Hydrogen
  • FIG. 12B shows a Germanium Radical Tool weakly bonded to a spent
  • FIG. 12C shows a Germanium Radical Tool breaking bond to spent Hydrogen
  • FIG. 12D shows a refreshed Hydrogen Abstraction Tool
  • FIG. 13A shows abstracting hydrogen from a workpiece
  • FIG. 13B shows a GermylMethylene Tool being position in close proximity to a radical carbon atom
  • FIG. 13C shows a GermylMethylene Tool bonded to a CH2 group
  • FIG. 13D shows a Hydrogen Donation Tool positioned to donate a hydrogen atom to the CH2 group
  • FIG. 13E shows hydrogen transferred to radical site on CH2 group and a
  • FIG. 14A shows a GermylMethylene Tool bonded to the third methylene group of a chain of three methylene groups that has been bonded to an adamantane workpiece
  • FIG. 14B shows the third methylene group rotated to a different position relative to the chain of three methylene groups attached to an adamantane workpiece, using a GermylMethylene Tool
  • FIG. 14C shows the chain of three methylene groups rotated into a cagelike configuration relative to an adamantane workpiece, using a GermylMethylene Tool bonded to the third methylene group in the chain of three methylene groups;
  • FIG. 14D shows the configuration of FIG. 14C after a first hydrogen atom has been abstracted from a sidewall carbon atom of the adamantane workpiece;
  • FIG. 14E shows the configuration of FIG. 14D after a second hydrogen atom has been abstracted from the same sidewall carbon atom of the adamantane workpiece;
  • FIG. 14F shows the chain of three methylene groups bonded to a sidewall carbon atom of the adamantane workpiece, thus closing a ring of three methylene groups, with the GermylMethylene Tool still attached;
  • FIG. 14G shows the configuration of FIG. 14F after the GermylMethylene
  • FIG. 14H shows the adamantane workpiece with a fully passivated three- methylene ring attached between two sidewall sites;
  • FIG. 15A shows a Germanium Radical Tool bonded to a spent Hydrogen
  • FIG. 15B shows a resulting Hydrogen Transfer Tool
  • FIG. 16A shows a bootstrap sequence for a proto-Hydrogen Abstraction tip
  • FIG. 16B shows the result when the proto-Hydrogen Abstraction tip is
  • FIG. 17A shows proto-Silicon Radical tip being converted to a proto-Silicon
  • FIG. 17B shows the converted proto-Silicon Hydrogen Donation tip
  • FIG. 18A shows charging a proto-Silicon Radical tip
  • FIG. 18B shows fabrication of a proto-Silicon Methylene tip
  • FIG. 19A shows a small section of diamond C(l 10) surface representing an atomically-precise workpiece upon which the C(l 10) surface is exposed;
  • FIG. 19B shows a diamond C(l 10) atomically-precise workpiece surface with a CH3 group bonded to a specific atom on the left side of a trough;
  • FIG. 19C shows a diamond C(l 10) atomically-precise workpiece surface with a CH3 group bonded to a specific atom on the left side of a trough and a second methyl group bonded to a specific neighboring atom on the right side of the same trough;
  • FIG. 19D shows two CH2 groups bonded across a trough on a diamond
  • FIG. 20 shows a flow chart for workpiece specification.
  • FIG. 21 shows a flow chart for mechanosynthesis reaction design.
  • FIG. 22 shows a flow chart for carrying out mechanosynthetic reactions.
  • FIG. 23 shows a flow chart for a reaction testing procedure.
  • FIG 24 shows the starting surface for a pyramid build sequence.
  • FIG. 25 shows the results of one application of a row-building sequence used to create pyramid-like structures.
  • FIG 26 shows the results of repeated applications of a row-building sequence to form a complete row.
  • FIG 27 shows the results of repeated applications of a row building sequence to generate multiple layers.
  • FIG 28 shows the results of repeated applications of a row building sequence, resulting in multiple complete layers.
  • FIG. 29 shows a nearly-complete pyramidal structure.
  • FIG 30 shows one form of a complete pyramidal structure, the uppermost atom being Carbon.
  • FIG 31 shows the starting structure for an alternative manner of completing a pyramidal structure.
  • FIG 32 shows another form of a complete pyramidal structure, the uppermost atom being Germanium.
  • FIG 33 shows a starting structure for reaction C002.
  • FIG 34 shows a starting structure for reaction C004.
  • FIG 35 shows a starting structure for reaction C006.
  • FIG 36 shows a starting structure for reaction C008.
  • FIG 37 shows an ending structure for reaction C008.
  • FIG 38 shows a starting structure for reaction M002.
  • FIG 39 shows a starting structure for reaction M004.
  • FIG 40 shows a starting structure for reaction M006.
  • FIG 41 shows a starting structure for reaction M008.
  • FIG 42 shows an ending structure for reaction M008.
  • FIG 43 shows a starting structure for reaction M009.
  • FIG 44 shows an ending structure for reaction M009.
  • FIG 45 shows a starting structure for reaction M01 1.
  • FIG 46 shows an ending structure for reaction M011.
  • FIG 47 shows a starting structure for reaction MO 12.
  • FIG 48 shows an ending structure for reaction M012.
  • FIG 49 shows a starting structure for reaction M014.
  • FIG 50 shows an ending structure for reaction M014.
  • FIG 51 shows a starting structure for reaction R003.
  • FIG 52 shows an ending structure for reaction R003.
  • FIG 53 shows a starting structure for reaction R004.
  • FIG 54 shows a starting structure for reaction R005.
  • FIG 55 shows a starting structure for reaction R006.
  • FIG 56 shows an ending structure for reaction R006.
  • An "adamantane” molecule comprises a 3D cage structure of ten carbon atoms, each terminated with one or two hydrogen atoms, having the chemical formula CI OH 16 and representing the smallest possible unit cage of crystalline diamond.
  • adamantane molecular structure is a molecular structure that is similar to and may include a single adamantane molecule, but also includes adamantane molecules which (1) may lack one or more terminating atoms, (2) may be covalently bonded to one or more neighboring adamantane cages in various well-known crystallo graphic lattice geometries, and (3) may employ elements other than carbon and hydrogen to form equivalent cage or crystallo graphic lattice geometries.
  • an "adamantane-like molecular structure” is (1) any polycyclic closed shell molecular structure composed entirely of carbon, nitrogen, oxygen and hydrogen, or (2) any molecular structure as in (1) that has been modified by substituting one or more atoms which, in the substituted molecular structure, have similar valence to the substituted carbon, nitrogen, oxygen or hydrogen atoms.
  • an adamantane-like molecular structure would include adamantane, polymantanes,
  • heteroadamantanes iceane, cubane, pagodane, dodecahedrane, cage or polycyclic
  • An "atom” includes the standard use of the term, as well as a radical, which, for example, may be just a proton in the case of H + .
  • the "bridgehead position" of an adamantane-like molecular structure refers to a structural atom that is bonded to three other structural atoms and is terminated by one or more nonstructural atoms.
  • a "chemical bond” is an interatomic covalent bond or an interatomic ionic bond, as these terms are commonly understood by practitioners skilled in the art.
  • a “chemical reaction” is said to occur when chemical bonds are formed or broken, or when the directionality, strength, or other salient characteristics of an existing chemical bond is altered, as for example during positionally controlled bond bending.
  • a “coaxial” reaction or trajectory is one in which the bond broken and the bond formed lies on the same line.
  • Diamond is a hydrocarbon adamantane molecular structure consisting of repeating adamantane cage units arranged in various well-known crystallographic lattice geometries.
  • Diamond materials include any stiff covalent solid that is similar to diamond in strength, chemical inertness, or other important material properties, and possesses a three-dimensional network of bonds. Examples of such materials include but are not limited to (1) diamond, including cubic and hexagonal lattices and all primary and vicinal crystallographic surfaces thereof, (2) carbon nanotubes, fullerenes, and other graphene structures, (3) several strong covalent ceramics of which silicon carbide, silicon nitride, and boron nitride are representative, (4) a few very stiff ionic ceramics of which sapphire (monocrystalline aluminum oxide) is representative, and (5) partially substituted variants of the above that are well-known to those skilled in the art.
  • Feedstock is the supply of atoms used to perform mechanosynthetic reactions on a workpiece.
  • Feedstock may take the form an atom or atoms (a molecule), including radicals (e.g., .GeH2, .CH2).
  • a "handle structure” comprises a plurality of atoms whose bonding pattern or electronic state is not altered during a site-specific mechanosynthetic chemical reaction and whose primary function is to hold a mechanosynthetically active tip or tool in a fixed geometric relationship that will permit a mechanosynthetic chemical reaction to proceed when the handle is manipulated by a positional device.
  • Handle structure may include the null case.
  • An "inert environment” includes, but is not limited to, UHV, helium, neon, or other noble gases either individually or in combination, or other gases or liquids that do not react with the tip or workpiece during mechanosynthetic operations.
  • "Mechanical force” may include applied mechanical forces having positive, negative, or zero magnitude. Chemical reactions driven by the application of mechanical force include reactions that are (1) driven through its reaction barrier by mechanically forcing reactants or products through the transition state, or (2) potentially reactive sites are driven away from a competing undesired reaction by mechanically restraining potentially reactive sites from attaining closer physical proximity, or (3) allowed to occur by bringing potentially reactive sites into closer physical proximity when zero mechanical force is required to do so, as for example when no reaction barrier exists.
  • a "mechanosynthetically active tip” is a tip controlled by a positional device that can perform mechanosynthetic reactions.
  • a “mechanosynthetic reaction” (sometimes referred to as a “reaction” when context makes it clear that the reaction is mechanosynthetic) is an individual chemical reaction that is driven to completion by the application of mechanical force.
  • a "mechanosynthetic reaction sequence” (sometimes referred to as a "reaction sequence” when context makes it clear that the reaction sequence is mechanosynthetic) is a series of reactions arranged in an ordered sequence that permits the fabrication of complex atomically-precise structures comprising a plurality of atoms and chemical bonds. Also referred to as a build sequence.
  • a “positional device” is a device capable of exerting atomically-precise positional control on a mechanosynthetic tip, tool, or workpiece, and may include, but is not limited to, a conventional scanning probe microscope (SPM) such as an atomic force microscope (AFM), a miniaturized or MEMS-scale SPM or AFM, a robotic arm mechanism of any size scale, or other appropriate manipulation system capable of atomically-precise positional control.
  • SPM scanning probe microscope
  • AFM atomic force microscope
  • AFM atomic force microscope
  • robotic arm mechanism of any size scale or other appropriate manipulation system capable of atomically-precise positional control.
  • a "pathological side reaction” is an undesired reaction which may happen in the course of mechanosynthesis, such as bonding feedstock to the wrong atom on a workpiece, or a rearrangement of atoms on a workpiece due to instability of an intermediate structure during the building process.
  • the "sidewall position" of an adamantane-like molecular structure refers to a structural atom that is bonded to two other structural atoms and is terminated by one or more nonstructural atoms.
  • Site-specific refers to knowing, and being able to constrain, with the necessary degree of reliability, the site at which mechanosynthetic reactions take place.
  • a "structural atom" in an adamantane-like molecular structure refers to an atom comprising the cage framework, for example a carbon atom in an adamantane molecule.
  • a "structural substituent atom” is an atom that occupies either a bridgehead or a sidewall position in an adamantane-like molecular structure.
  • a "terminating atom" in an adamantane-like molecular structure refers to an atom that does not serve as a constituent atom in the cage structure but absorbs unused valences of a structural atom comprising the cage framework, for example a hydrogen atom in an adamantane molecule.
  • a "three-dimensional" workpiece means a workpiece composed of a lattice of atoms which occupies three dimensions if an individual atom is assumed to be without size. Similarly, a two-dimensional workpiece would be composed of a plane of atoms.
  • a "tool” is a mechanosynthetically active tip covalently bonded to a handle structure.
  • a "toolset” is a selected set of mechanosynthetic tools.
  • a "tip” is a device for facilitating mechanosynthetic reactions which includes one or more "active” atoms whose bonding pattern or electronic state is altered during a mechanosynthetic operation, and one or more "support” atoms whose bonding pattern or electronic state is not altered during a mechanosynthetic operation.
  • the support atoms function to hold the active atoms in position.
  • a tip may be atomically-precise or imprecise.
  • a "transfer passivating atom” is an atom that passivates one or more open valences of a transfer substituent atom.
  • a "transfer substituent atom” is an atom that terminates a structural substituent atom via a single covalent bond, and that may be chemically transferred to a workpiece during a site-specific positionally-controlled mechanosynthetic chemical reaction driven by the application of mechanical force.
  • a "workpiece” is an object built via mechanosynthesis.
  • a workpiece may be, or include, feedstock, tools, waste atoms, intermediate structures, combinations thereof, or other objects.
  • a system may have more than one workpiece.
  • a dot is frequently used in chemical structures herein to represent an electron, as in the radical group ".CH2".
  • the notation herein generally omits subscript, in favor of simply writing the number in-line (again, as in ".CH2"), as its meaning is still clear and unambiguous.
  • Superscript may be written using the " A " character when required for clarity.
  • the invention is used to fabricate atomically-precise, multi-atom structures.
  • the present invention has many advantages, including the ability to fabricate complex structures to atomically-precise specifications, the ability to position individual atoms or groups of atoms in specific locations on a workpiece, the ability to remove specific groups of atoms from specific sites on a workpiece, the ability to make atomically-precise
  • the present invention provides a pathway for the creation of a set of mechanosynthetic molecular tools that are able to fabricate the self-same set, refresh all tools in the set, allow for numerous reactions using many elements, and create diverse workpieces, including many-atom, three dimensional structures. Described is a set of mechanosynthetic tools that achieves all these objectives, and then described is a bootstrap process to build the first set of such tools.
  • the set of mechanosynthetic molecular tools comprises: (1) the Hydrogen
  • the bootstrap tools are:
  • FIG. 1A illustrates the active tip of the
  • Hydrogen Abstraction Tool 100 which is used to selectively abstract a single hydrogen atom from a workpiece. Hydrogen Abstraction Tool 100 is shown prior to the abstraction of a hydrogen atom.
  • the distal carbon atom 102 is a radical with a high affinity for hydrogen. Carbon atoms 102 and 104 are triply bonded to each other and in this and other structures are commonly referred to as "an ethynyl radical" or a "dimer.” The ethynyl radical is bonded to carbon atom 106, called a "bridgehead” carbon atom.
  • the remainder of the adamantane cage consists of 10 carbon atoms and the hydrogen atoms which terminate them.
  • the 6 carbon atoms at the base of the adamantane cage i.e., the six carbon atoms in the adamantane cage most distant from carbon atom 106 in FIG. 1A
  • a handle structure by which the tool is positioned.
  • the Hydrogen Abstraction Tool is used by positioning the tool so that carbon atom 102 is in close proximity (e.g., one or two angstroms) to a hydrogen atom which is to be abstracted.
  • FIG. 2 illustrates the Hydrogen Donation
  • the hydrogen atom 122 is bonded to germanium atom 124. Because the bond between germanium atom 124 and hydrogen atom 122 is not as strong as the bond that can be formed between hydrogen atom 122 and a carbon radical on a workpiece, the hydrogen atom 122 will, when positioned close to a carbon radical and with the application of mechanical force to overcome reaction barriers, transfer to that carbon radical and so donate a hydrogen to it.
  • FIG. 3 illustrates the Germanium Radical
  • the germanium atom 132 is a radical.
  • the Germanium Radical Tool 130 results from the reaction that will occur when the Hydrogen Donation Tool 120 donates hydrogen atom 122 to a carbon radical.
  • FIG. 4 illustrates the Methylene Tool 140.
  • FIG. 5 illustrates the GermylMethylene Tool
  • the GermylMethylene tool can be used to transfer the .CH2 group 144 to a carbon radical site on a growing workpiece.
  • FIG. 6 illustrates the Germylene Tool 160 which can be formed by adding a .GeH2 group 162 to the Adamantane Radical Tool 180.
  • Germylene Tool 160 can be used in reaction sequences that add a germanium atom to a workpiece (and in particular, can be used during the synthesis of the Germanium Radical Tool 130).
  • FIG. 7 illustrates the Hydrogen Transfer
  • the Hydrogen Transfer Tool is particularly useful because the bond between carbon atom 102 and hydrogen atom 172 is particularly weak, making it an excellent hydrogen donation tool.
  • FIG. 8 illustrates the Adamantane Radical
  • Tool 180 which can be formed by abstracting a hydrogen atom from an exposed adamantane cage on any diamond surface located, e.g., at the terminus of a tip, producing a single carbon radical 182.
  • FIG. 9 illustrates the Dimer Placement Tool
  • a dimer 192 bonds to a tip which has two germanium atoms 194 and 196.
  • the two bonds between the dimer 192 and the two germanium atoms 194 and 196 are highly strained, making the resulting Dimer Placement Tool 190 reactive and suitable for adding a dimer to a growing workpiece, particularly when two adjacent radical sites are present on the workpiece to which the dimer can bond.
  • One way to provide hydrogen is from a presentation surface covered by hydrogen atoms (e.g., a bulk produced flat hydrogenated diamond surface).
  • One way to provide carbon is in the form of .CH2 groups distributed on a suitable presentation surface (e.g., on a bulk produced flat germanium surface). This also provides hydrogen, which may eliminate the need for an independent source for hydrogen.
  • germanium is in the form of .GeH2 groups distributed on a suitable presentation surface (e.g., on a bulk produced flat germanium surface).
  • Both carbon and germanium can also enter the system when provided as methyl or germyl groups (CH3 or GeH3) on a suitable presentation surface. In this case, they can be made chemically active by abstracting a hydrogen atom and converting them into .CH2 or .GeH2 groups respectively.
  • CH3 or GeH3 methyl or germyl groups
  • FIG. 10A illustrates the use of the Hydrogen Abstraction Tool 100 to selectively abstract hydrogen atom 202.
  • Hydrogen Abstraction Tool 100 is positioned so that radical carbon atom 102 is just above hydrogen atom 202 which is bonded to diamond surface 204.
  • Hydrogen Abstraction Tool 100 is brought into close proximity to diamond surface 204, the hydrogen atom 202 will bond to carbon atom 102, and thus transfer from diamond surface 204 to Hydrogen Abstraction Tool 100.
  • FIG. 10B illustrates the result of the transfer of the hydrogen atom 202 to the
  • Hydrogen Abstraction Tool 100 which serves to convert the Hydrogen Abstraction Tool 100 into a spent Hydrogen Abstraction Tool 110.
  • a reaction sequence transfers a hydrogen atom from a
  • Hydrogen Donation Tool to a diamond surface, both hydrogenating the radical site on the diamond surface and converting the Hydrogen Donation Tool to a Germanium Radical tool.
  • FIG. 11A illustrates the use of the Hydrogen Donation Tool 120 to selectively donate one hydrogen 122 atom to carbon radical 212 on diamond surface 204.
  • the Hydrogen Donation Tool 120 can be positioned directly above diamond surface 204 proximally close to carbon radical 212.
  • Hydrogen Donation Tool 120 is brought into close proximity to diamond surface 204 such that the attractive force between hydrogen atom 122 and carbon radical 212 exceeds the attractive force between the hydrogen atom 122 and the germanium atom 124, the hydrogen atom 122 will transfer from the germanium atom 124 and bond to the diamond surface 204 at the site of the carbon radical 212.
  • FIG. 1 IB illustrates the result of the transfer of the hydrogen atom 122 to carbon atom 212 (now no longer a radical), which serves to convert the Hydrogen Donation Tool 120 into a Germanium Radical Tool 130 now having a germanium radical 132.
  • a reaction sequence refreshes a Hydrogen Abstraction
  • FIG. 12A illustrates a Germanium Radical Tool 130 and a spent Hydrogen
  • FIG. 12B illustrates the germanium radical 222 of the Germanium Radical
  • FIG. 12C illustrates the germanium radical 222 of the first Germanium
  • FIG. 12D shows the resulting refreshed Hydrogen Abstraction Tool 100 and recovery of the original Germanium Radical Tool 130 unchanged.
  • a GermylMethylene Tool can be charged by starting with a Germanium Radical Tool and .CH2 groups distributed on a suitable presentation surface (e.g., germanium). The Germanium Radical Tool is touched to a .CH2 group on the presentation surface, and then withdrawn. Although the .CH2 group is bonded to a germanium atom on the presentation surface and to a germanium atom on the tip of the Germanium Radical Tool, the bond to the germanium atom on the tip of the
  • Germanium Radical Tool is stronger (the germanium on the tip of the Germanium Radical Tool is in a different atomic bonding environment than the germanium on the presentation surface— in particular, it is bonded to 3 carbon atoms rather than being bonded to other germanium atoms).
  • FIGS. 13A-E illustrate mechanosynthetic methylation of a selected atomic site.
  • workpieces will frequently be hydrogenated to eliminate dangling bonds and to avoid unexpected reconstructions. Some of these hydro genations, particularly when immediately followed by hydrogen abstraction, can simply be omitted.
  • the first step in the methylation sequence is to abstract a hydrogen atom from the specific site to allow addition of a CH3 group.
  • this general assumption is not used (i.e., when exposed radical sites are not immediately hydrogenated) there might be multiple radical sites available on the workpiece that could be methylated without first abstracting a hydrogen. In such cases, the step illustrated in FIG. 13A in the following sequence could be eliminated, and steps illustrated in FIG.
  • FIG. 13D and FIG. 13E might also be eliminated if there is no immediate need to hydrogenate this particular added .CH2 group, leaving only steps illustrated in FIG. 13B and FIG. 13C as required for this method.
  • the need (or lack thereof) for hydrogenation or dehydrogenation in a given case will be readily apparent to a practitioner skilled in the art.
  • FIG. 13A illustrates abstracting the hydrogen atom 232 that occupies the site where the methyl group is to be placed.
  • Hydrogen Abstraction Tool 100 abstracts hydrogen atom 232 from adamantane cage 234, which represents a few atoms from a larger diamond workpiece.
  • FIG. 13B illustrates GermylMethylene Tool 150 being positioned so that .CH2 group 144 is in close proximity to radical carbon atom 236. With the application of mechanical force to overcome reaction barriers, the .CH2 group 144 will then bond to radical carbon atom 236 as shown in FIG. 13C, the next step in the sequence.
  • FIG. 13C illustrates the GermylMethylene Tool 150 bonded to the .CH2 group
  • the GermylMethylene Tool 150 is withdrawn by the application of mechanical force, converting GermylMethylene Tool 150 into a Germanium Radical Tool (not shown) and the .CH2 group is left behind on the workpiece 234.
  • FIG. 13D illustrates a Hydrogen Donation Tool 120 which is positioned to donate hydrogen atom 238 to the radical site on the .CH2 group 240. With the application of mechanical force to overcome reaction barriers, hydrogen atom 238 is bonded to the .CH2 group 240.
  • FIG. 13E illustrates the result of the reaction in which the hydrogen on the
  • Hydrogen Donation Tool has been transferred to the radical site on .CH2 group 240, converting it to CH3 group 242.
  • the Hydrogen Donation Tool is converted by this process into Germanium Radical Tool 130.
  • This method can be applied to add a methyl group to virtually any exposed carbon radical on any hydrocarbon structure. It can also be used to add a methyl group to a wide range of other possible target structures.
  • FIG. 14A illustrates a structure to which three CH2 groups have already been added.
  • the first CH2 group 246 is attached to a sidewall site on adamantane cage 244, a cage that represents a few atoms from a larger diamond workpiece.
  • the second CH2 group 248 is added to the first CH2 group 246, and the third CH2 group 250 is added to the second CH2 group 248.
  • the GermylMethylene Tool 150 that is used to add the third CH2 group 250 (thus incorporating the final carbon atom 252 in the chain) is not withdrawn, but instead is left attached so that this tool can be used to re-position carbon atom 252.
  • the GermylMethylene Tool 150 is represented by a single germanium atom 254 and 3 attached hydrogen atoms 256, rather than the full adamantane cage structure of the GermylMethylene Tool 150 as shown in FIG. 5.
  • FIG. 14B illustrates the structure that results after CH2 group 250 has been rotated from the trans to the cis configuration relative to CH2 group 248, which is accomplished by the application of lateral forces transmitted through the handle of the attached GermylMethylene Tool 150.
  • FIG. 14C illustrates the structure that results after CH2 group 248 has been further rotated relative to CH2 group 246 such that the three CH2 groups 246, 248 and 250 are re-oriented into a cage-like configuration relative to the workpiece; this re-orientation is accomplished by the application of lateral forces transmitted through the handle of the attached GermylMethylene Tool 150.
  • FIG. 14C also shows the location of hydrogen atom 132 that will be abstracted in the next reaction step, and the location of hydrogen atom 112 that will be abstracted in the next reaction step after that.
  • FIG. 14D illustrates the workpiece 244 after the abstraction of hydrogen atom
  • FIG. 14D also shows the location of hydrogen atom 112 that will be abstracted in the next reaction step.
  • FIG. 14E illustrates the workpiece 244 after the abstraction of a second hydrogen atom 112 from the same carbon atom 258, which becomes a carbene diradical.
  • the two hydrogen abstractions that occur in FIG. 14D and FIG. 14E are not shown explicitly but require the use of two Hydrogen Abstraction Tools in the abstraction process.
  • FIG. 14F illustrates GermylMethylene Tool 150 being positioned so that carbene 258 inserts into the CH bond between carbon atom 252 and one of its attached hydrogen atoms with the application of mechanical force. Following this insertion reaction, carbon atom 252 will bond to carbon atom 258 via bond 260.
  • FIG. 14G illustrates the workpiece after the GermylMethylene Tool 150 is withdrawn, leaving carbon atom 252 attached to carbon atom 258. Carbon atom 252 is now, because of the withdrawal of GermylMethylene Tool 150, a radical.
  • FIG. 14H illustrates the state after the final step in the mechanosynthetic reaction sequence which is to hydrogenate the radical site at carbon atom 252 using a Hydrogen Donation Tool 120 (not shown).
  • the donation reaction which requires the application of mechanical force to overcome a reaction barrier, is not shown explicitly but requires the use of a Hydrogen Donation Tool.
  • carbon atom 252 has four bonds, two bonds to adjacent carbon atoms and two bonds to hydrogen atoms.
  • This mechanosynthetic reaction sequence results in a closed chain of 3 carbon atoms (derived from CH2 groups 246, 248 and 250) being added to workpiece 244.
  • GermylMethylene Tool 150 must be positionally rotated during this sequence.
  • An alternative method of changing the orientation of GermylMethylene Tool 150 is to perform a handle exchange, substituting a new tool in a new orientation for the existing GermylMethylene Tool 150.
  • a hydrogen atom is first abstracted from CH2 group 250 at the tip of the attached GermylMethylene Tool 150, creating a radical site at carbon atom 252 to which a new Germanium Radical Tool which is already in the desired new orientation (and precisely positioned in X, Y and Z) can next be bonded.
  • atomically-precise handle structures can be fabricated that will be suitable for supporting the various tips illustrated in FIGS. 1-9.
  • Hydrogen Abstraction Tool recharge sequence shown in FIG. 12 to convert the Germanium Radical Tool to a Hydrogen Donation Tool.
  • GermylM ethylene Tool Starting with the Germanium Radical Tool, we bond the Germanium Radical Tool to a .GeH2 group on a suitable presentation surface (e.g., germanium). The reaction energetics favor transfer of the .GeH2 group to the tool from a germanium presentation surface. We then retract the tool, producing a GermylMethylene Tool.
  • a suitable presentation surface e.g., germanium
  • a second Germanium Radical Tool is constructed in a lonsdaleite polytype configuration on the side of the first Germanium Radical Tool, yielding a discharged Dimer Placement Tool which is then recharged with C2 dimer by the addition of two carbon atoms using two GermylM ethylene Tools, followed by the abstraction of four hydrogen atoms using four applications of Hydrogen Abstraction Tools.
  • Adamantane Radical Tools can be charged with .CH2 groups, producing as many Methylene Tools as desired. And, with the availability of a suitable presentation surface for .GeH2 groups, the Adamantane Radical Tools can be charged with .GeH2 groups, producing as many Germylene Tools as desired.
  • the Germylene Tools along with the previously available tools, allows the fabrication of as many Germanium Radical Tools as desired, which in turn allows the fabrication of as many GermylM ethylene Tools and as many Hydrogen Donation Tools as desired. Combining spent Hydrogen Abstraction Tools and Germanium Radical Tools allows the fabrication of as many Hydrogen Transfer Tools as desired. Finally, as many Dimer Placement Tools as desired can be fabricated using the previous tools.
  • the first atomically-precise tools can be used to fabricate more of the self-same tools. But the first set of atomically-precise tools must be manufactured using only currently available atomically imprecise tools, or proto-tools, a process called bootstrapping. Numerous approaches exist for bootstrapping the first atomically-precise tools from proto-tools.
  • AFM tip functionalization is well-known in the prior art. Wong, S., Woolley, A., et al. (1999) "Functionalization of carbon nanotube AFM probes using tip-activated gases.” Chemical Physics Letters(306): 219-225. See also, Grandbois, M., Dettmann, W., et al. (2000) "Affinity Imaging of Red Blood Cells Using an Atomic Force Microscope.” Journal of Histochemistry & Cytochemistry(48): 719-724. See also, Hafner, J., Cheung, C, et al.
  • the present invention describes a set of nine molecular tools sufficient to make additional sets of the self-same tools (the "minimal toolset") as described above. These tools are illustrated in FIGS. 1-9. Given an adequate initial number of each of these nine tools, with the tools being positionally controlled by suitable positional devices and given suitable presentation surfaces for feedstock, it is possible to build additional sets of the selfsame tools.
  • the first toolset must be built without the benefit of a previously existing toolset. Thus, this first toolset must be fabricated from simpler proto-tools using methods that are experimentally accessible. Once such a bootstrap process has been executed, yielding a first set of tools in small but adequate numbers, the bootstrap process need not be repeated again.
  • each reaction sequence comprising the bootstrap process need only be carried out a small number of times.
  • any methods (even those that would be too expensive or unreliable for continued use) of building the first set of tools are sufficient to enable the fabrication of more tools.
  • These methods can be carried out at low temperature (e.g., 77K-80 K is readily available using liquid nitrogen, or 4 K using liquid helium) and by the use of proto-tools having only modest reliability. Reducing the
  • Abstraction and Hydrogen Donation Tools With a small but adequate initial supply of these two tools, when operated with appropriate positional control in an inert environment, and when provided with a source of feedstock (e.g., .CH2, .GeH2 and H distributed on a source of feedstock (e.g., .CH2, .GeH2 and H distributed on a source of feedstock (e.g., .CH2, .GeH2 and H distributed on
  • Bootstrap processes are simplified by following the general principle that feedstock is moved downhill in energy or bonding force as it is transferred, for example, from the feedstock presentation surface, to the tip, and finally to the workpiece. While other sequences are possible (e.g., when removing atoms from a workpiece) the principle is the same: design the combination of feedstock, tip, and workpiece so that the desired reactions are favored by the net energy change or binding force differences.
  • the presentation surface is germanium (which forms relatively weak bonds) and the feedstock is .CH2, .GeH2 or even more simply just a single hydrogen atom H
  • a silicon tip will bond to the feedstock more strongly than the germanium surface bonds to the feedstock.
  • the workpiece is a stiff hydrocarbon structure
  • the feedstock e.g., H, .CH2, or .GeH2
  • the feedstock's net energy decreases, or bonding force increases, as it transfers from the presentation surface, to the tip, and finally to the workpiece.
  • FIG. 16A illustrates how a bootstrap sequence may start with the fabrication of a proto-Hydrogen Abstraction tip.
  • the proto-Hydrogen Abstraction tip 270 shown in FIG. 16B differs from the Hydrogen Abstraction Tool 100 shown in FIG. 1 in that the proto- Hydrogen Abstraction tip does not necessarily have an atomically-precise adamantane cage at the base of the ethynyl radical.
  • the particular proto-Hydrogen Abstraction tip 270 is but one instance of an entire class of structures that incorporates some degree of randomness in the fabrication process but which still has the requisite properties.
  • the proto-Hydrogen Abstraction tip it is sufficient that the ethynyl radical is in place and functions.
  • One method of preparing the first proto-Hydrogen Abstraction tip is by the following five-step sequence.
  • C2 dimers are chemisorbed onto an appropriate presentation surface.
  • the preparation may begin with the direct adsorption of C2 dimers 262 onto a depassivated surface 264 (or into a matrix) which may be, among other possibilities, copper, frozen noble gases (or similarly unreactive compounds), germanium, germanium carbide, graphene, silicon carbide, or platinum.
  • a sub-nanometer radius diamond tip 266 is at least partially depassivated by any of several methods, which might include: (A) heating to an appropriate temperature (e.g., 700-800 K for diamond C(l 11) and C(100) surfaces), (B) contacting the tip to an already depassivated surface (e.g., a surface with an equal or higher affinity for hydrogen), or (C) by the standard practice of applying a suitable voltage pulse to cause removal of one or more hydrogen atoms from the tip. This produces at least one radical site 268 on the tip.
  • an appropriate temperature e.g., 700-800 K for diamond C(l 11) and C(100) surfaces
  • an already depassivated surface e.g., a surface with an equal or higher affinity for hydrogen
  • C by the standard practice of applying a suitable voltage pulse to cause removal of one or more hydrogen atoms from the tip. This produces at least one radical site 268 on the tip.
  • the tip 266 is brought into contact with one end of a chemisorbed dimer 262, resulting in the dimer bonding to the tip, possibly requiring the application of mechanical force to overcome reaction barriers.
  • a "test and repeat" step may be employed to ensure that the resulting proto-Hydrogen Abstraction tip has been made successfully, if increased reliability is desired.
  • the resulting proto-Hydrogen Abstraction tip can then be used to selectively abstract hydrogen in subsequent mechanosynthetic steps.
  • the minimal toolset as described in Freitas and Merkle (2008)
  • the above steps serve to produce a sufficient number of proto-Hydrogen
  • a proto-Hydrogen Donation tip will be effective at donating hydrogen atom to a carbon radical on a diamond workpiece.
  • the hydrogenated ultrasharp silicon tip is designated as a proto-Silicon Hydrogen Donation tip.
  • a functionally equivalent tool may substitute a silicon atom in place of germanium atom 124 in the Hydrogen Donation Tool illustrated in FIG. 2.
  • germanium in the toolset rather than silicon The primary reason for using germanium in the toolset rather than silicon is the higher reliability of operation with germanium.
  • the substitution of a silicon tip for a germanium tip also works as required for the reactions needed during the bootstrap sequence. Silicon, being one row closer than germanium to carbon, has bond strengths to carbon atoms that are intermediate in strength between C-C bonds and C-Ge bonds. As a result the critical reactions used during the bootstrap sequence will work with silicon substituted for germanium but will have lower reliability at any given operating temperature. Lowering the temperature of operation recovers much of the foregone reliability. Thus the use of commercially available silicon tips with ⁇ 2 nm radii will suffice because lower temperature operation during the bootstrap sequence is readily available, and because lower-reliability processes are tolerable during bootstrapping.
  • Proto-Hydrogen Abstraction tips and proto-Silicon Hydrogen Donation tips are then used to fabricate the rest of the tips in the bootstrap process, followed by all the tools in the minimal toolset as described below.
  • a hydrogen atom is donated from the proto-Silicon Hydrogen Donation tip to the diamond surface, thus creating a radical site on the tip.
  • the resulting tip is designated as a proto- Silicon Radical tip. This provides the functionality of the Germanium Radical Tool for some or all of the bootstrap sequence.
  • the proto-Silicon Radical tip also may be fabricated by abstracting a hydrogen atom from the proto-Silicon Hydrogen Donation tip using the proto-Hydrogen Abstraction tip.
  • a wide range of possible proto-radical tips may be used, and there are many methods of manufacturing any particular tip, as for example: (1) heating a workpiece diamond, silicon or germanium tip to a temperature sufficient to drive off some of the hydrogen atoms on the tip (e.g., 700-800 K for diamond C(l 11) and C(100) surfaces), (2) employing the standard practice of applying a voltage pulse of appropriate magnitude and duration at the workpiece tip to remove one or more hydrogen atoms, or (3) applying a proto- Hydrogen Abstraction tip or Hydrogen Abstraction Tool to the workpiece tip.
  • FIG. 17A illustrates the proto-Silicon Radical tip 272 being converted to the proto-Silicon Hydrogen Donation tip 278 illustrated in FIG. 17B by touching tip 272 to a hydrogen atom 274 on a suitable presentation surface 276.
  • a suitable presentation surface 276 Of the many possible such presentation surfaces that would be suitable, an obvious choice is a hydrogenated germanium surface. This surface, upon contact by proto-Silicon Radical tip 272, transfers hydrogen atom 274 from the germanium surface 276 (where the hydrogen is more weakly bound to a germanium) to the proto-Silicon Radical tip 272 (where the hydrogen is more strongly bound to a silicon atom).
  • the resulting proto-Silicon Hydrogen Donation tip 278 makes a suitable hydrogen donation tool.
  • the proto-Silicon Radical tip is touched to a .CH2 group on a suitable presentation surface to create the functional equivalent of a GermylMethylene Tool.
  • This functional equivalent may be called a proto-Silicon Methylene tip.
  • any radical tip including the proto-Silicon Radical tip, can be charged by using many possible methods, as exemplified by the following series of steps illustrated by FIG. 18A:
  • CH3 groups are distributed on a suitable presentation surface 264.
  • a proto-Hydrogen Abstraction tip removes a selected hydrogen from a specific CH3 group chemisorbed to the presentation surface, leaving .CH2 group 282 chemisorbed to presentation surface 264.
  • Proto-Silicon Radical tip 266 approaches .CH2 group 282 (chemisorbed to presentation surface 264).
  • the proto-Silicon Methylene tip 284 is withdrawn from presentation surface 264 by the application of mechanical force, taking .CH2 group 282 with it, resulting in the fabrication of proto-Silicon Methylene tip 284 from proto-Silicon Radical tip 266. Because of the relatively low reliability and the possibility of positioning errors while using these early tips, it may be necessary to test the tip after the fifth step to determine if .CH2 group 282 has in fact attached to proto-Silicon Radical tip 284 upon its withdrawal.
  • Tools generally have a tip and a handle, the handle being a mounting point for the tip.
  • a suitable handle can be fabricated by starting with a small bulk- produced diamond surface. While various diamond surfaces can be used, the ring closure reactions are particularly simple when the diamond C(l 10) surface is used.
  • FIG. 19A illustrates this surface consisting of staggered rows of atomic-scale troughs. Fabrication of additional C(l 10) surface takes place when a zig-zag chain of carbon atoms is emplaced straddling the length of an existing trough. Two zig-zag chains added in adjacent troughs form a new trough between them, atop which an additional chain of carbon atoms can be added. Construction of a single zig-zag chain can proceed by adding single carbon atoms to the end of the chain.
  • Fabrication of a suitable handle using the proto-tools starting with a hydrogenated diamond C(l 10) surface begins as follows: (1) abstract a single hydrogen from the surface using a proto-Hydrogen Abstraction tip, creating a radical site; (2) add a .CH2 group at the radical site using a proto-Silicon Methylene tip; and (3) add a hydrogen atom to the added .CH2 group using a proto-Silicon Hydrogen Donation tip.
  • FIG. 19B illustrates how this three-step reaction sequence adds a CH3 group containing carbon atom 292 to the left hand side of a trough on the C(l 10) surface.
  • FIG. 19C illustrates how an additional CH3 group containing carbon atom 294 is added by the same method on the right side of the trough.
  • two proto-Hydrogen Abstraction tips are applied, one to each methyl group, yielding two .CH2 groups in which both carbon 292 and carbon 294 are radicals, which then bond via radical coupling to form a single CH2CH2 group, constituting one "zig" of a zig-zag chain on the C(l 10) surface, as illustrated in FIG. 19D.
  • a "zag” is then added by bonding in similar manner a third methyl group on the left hand side of the trough next to the attachment site of the first methyl group, across the trough from the attachment site of the second methyl group.
  • a sequential application of two more proto-Hydrogen Abstraction tips to the second CH2 group and the third methyl group yields two new radical sites which then bond via radical coupling, now forming a three-carbon CH2CHCH2 "zig-zag" sequence straddling the trough of the C(l 10) surface. This process is continued to produce the first zig-zag chain of desired length in the lowest (most
  • This method is used to fabricate a new layer of the C(l 10) surface, on top of the original surface, of some specific desired size. The process is then repeated, building up a second new layer that is slightly smaller in both lateral dimensions than the first. A third layer, similarly slightly smaller than the second layer, continues this process. Additional new layers decreasing in lateral extent are fabricated until the apex of the resulting pyramid is small enough (e.g., the width of a single adamantane cage) to provide a suitable base for the intended tool whose handle is being manufactured.
  • the proto-tools including the proto-Hydrogen Abstraction tip, the proto-
  • Silicon Hydrogen Donation tip the proto-Silicon Radical tip, and the proto-Silicon
  • the proto-Hydrogen Abstraction tip would be used in place of the Hydrogen Abstraction Tool
  • the proto-Silicon Radical tip would be used in place of the Germanium Radical Tool
  • the proto-Silicon Methylene tip would be used in place of the GermylM ethylene Tool
  • the proto-Silicon Hydrogen Donation tip would be used in place of the Hydrogen Donation Tool.
  • the tip culminates in a single bridgehead carbon atom at the apex of a pyramid structure constructed as described above.
  • the bridgehead carbon atom apex is either manufactured in an unhydrogenated state or is dehydrogenated after manufacture using a proto-Hydrogen Abstraction tip or Hydrogen Abstraction Tool.
  • This sequence of reactions for building the Adamantane Radical Tool is very simple because it requires only the application of a single tool or tip at a time to build the necessary handle structure. Since the handle is built layer by layer, the aspect ratio of the initial bootstrapped tips that are used during the fabrication process can be quite poor because the workpiece is geometrically accessible and all multi-tip operations are eliminated. The aspect ratio of the manufactured tools is improved during successive tool-building iterations.
  • the Hydrogen Abstraction Tool is fabricated by touching the radical at the tip of the Adamantane Radical Tool to a C2 dimer on a suitable presentation surface.
  • the Adamantane Radical Tool is also used to make the Methylene Tool by touching the radical tip of the Adamantane Radical Tool to a .CH2 group on a suitable presentation surface, in a method analogous to that used during the bootstrap procedure to fabricate the proto-Silicon Methylene tip.
  • the Adamantane Radical Tool is used to make a Germylene Tool or the proto-Silicon Radical tip is used to make a proto-Silicon Germanium tip.
  • the Germylene Tool and the proto-Silicon Germanium tip have similar functionality, so the choice about which one to use during the bootstrap sequence depends on specific issues of implementation convenience that will be evident to practitioners skilled in the art.
  • the Germylene Tool (or the proto-Silicon Germanium tip if fabricated) can be fabricated by touching an Adamantane Radical Tool or a proto-Silicon Radical tip
  • Either the Germylene Tool or the proto-Silicon Germanium tip can then be used during fabrication of the first Germanium Radical Tool.
  • the reaction sequence used with the proto-Silicon Germanium tip is simpler than the reaction sequence used with the Methylene Tool.
  • the Germanium Radical Tool can be fabricated by a sequence of reactions similar to those described for the Adamantane Radical Tool and illustrated in FIG. 19, with but one exception.
  • the single use of the proto-Silicon Methylene tip that adds the carbon atom destined to be the radical carbon at the tip of the Adamantane Radical Tool is replaced by a single use of either (1) the Germylene Tool or (2) the proto-Silicon Germanium tip, as is convenient. The remaining reactions in the sequence continue as before.
  • the Germanium Radical Tool can be charged by touching it to a .CH2 on a suitable presentation surface, analogous to the previously described methods, producing the first GermylMethylene Tool.
  • Germanium Radical Tool can also be used to make the Hydrogen
  • the Hydrogen Abstraction Tool must first be used to abstract a hydrogen atom, creating a spent Hydrogen Abstraction Tool 110 requiring recharge. Then the Germanium Radical Tool 130 will bond to the spent Hydrogen Abstraction Tool 110 at the distal carbon atom 102. A second Germanium Radical Tool 224 then abstracts hydrogen 112 from the tip of the spent Hydrogen Abstraction Tool 110 to produce a new Hydrogen Donation Tool 120. The bonded Hydrogen Abstraction Tool 100 and the first Germanium Radical Tool 130 are then separated, regenerating both.
  • the Hydrogen Transfer and Dimer Placement Tools [0316] As illustrated in FIG. 15, the Hydrogen Transfer Tool is fabricated by bonding a Germanium Radical Tool 130 to a spent Hydrogen Abstraction Tool 110.
  • the Dimer Placement Tool can be made using the previous tools. The entire nine-tool minimal toolset has now been fabricated.
  • Hydrogen Abstraction tip (2) Proto-Silicon Hydrogen Donation tip, (3) Proto-Silicon Radical tip, (4) Proto-Silicon Methylene tip, (5) Adamantane Radical Tool, (6) Hydrogen Abstraction Tool, (7) Methylene Tool, (8) Germylene Tool, (9) Proto-Silicon Germanium tip (optional), (10) Germanium Radical Tool, (11) GermylMethylene Tool, (12) Hydrogen Donation Tool, (13) Hydrogen Transfer Tool, and (14) Dimer Placement Tool.
  • Other sequences will be apparent to practitioners skilled in the art and having the benefit of the teachings presented herein.
  • Bootstrapping a set of mechanosynthetic tools requires careful consideration of the reactions involved. It can be simplified by the use of additional reactions, elements, conditions, or mechanisms that are used primarily or only during the bootstrap sequence. For example, if reactions are carried out at low temperature, then reliability problems which are exacerbated by thermal noise and thermally induced errors can be reduced. Low temperature operation also allows the use of alternative reactions that might have unacceptably low reliability at higher temperatures. Auxiliary tips and processes can be introduced to simplify the steps in the bootstrap sequence. The mechanisms for providing feedstock and for disposing of excess atoms can also be chosen to simplify the bootstrap process.
  • a tetrahedral structure with respect to the apical atom can be useful as, with a feedstock atom bound to one leg of the tetrahedron, the other three bonds serve to stabilize the apical atom when force is applied during a reaction.
  • AX4 tetrahedral
  • AX5- AX8 hybridizations can also provide the necessary free electrons to bond a feedstock atom while having the ability to form at least three other bonds to create a rigid tip structure. The primary concern is simply whether or not a given tip will reliably perform the intended reaction.
  • C9H14[A1,B,N,P] have the apical atom, to which the feedstock atom is attached, at the sidewall position of an adamantane frame.
  • C9H15[C,Si,Ge] have the apical atom, to which the feedstock atom is attached, at the bridgehead position of an adamantane frame.
  • the notation for the workpieces are the same, except that the apical atoms are listed first.
  • the reaction where a C914A1 tip using a Be feedstock atom donates the feedstock atom to CC9H15 could be expressed as:
  • Many computational chemistry programs allow the creation of models based on atomic coordinates, or algorithms to generate such coordinates.
  • a build sequence can be created that specifies the order in which each atom is to be added to, or removed from, the workpiece. Reactions that do not add or remove atoms are also possible, such as those that change the bonding structure of the workpiece.
  • the reaction parameters including the tip, tip trajectory, feedstock, reaction temperature, and possible reaction pathologies are determined. These topics are addressed herein. Where additional reactions are desired beyond those that we present, it will be obvious to one skilled in the art how to determine new reactions using the teachings and data herein as a guide.
  • FIG. 32 which is capped with C
  • FIG. 30, which is capped with Ge
  • This structure has multiple uses. With the apical Ge atom, it can serve as a Germanium Radical tool. Terminated with a carbon ring-closure reaction, omitting the Ge, the structure can serve as an Adamantane Radical tool. And, given the size and stepped nature of the walls, such a structure (or multiple such structures built a known distance apart) could serve as calibration standards for SFM or AFM-based metrology.
  • Hbst Hydrogen Abstraction tool
  • HDon Hydrogen Donation tool
  • GeRad Germanium Radical tool
  • GM GermylMethylene tool
  • MO 14 The final step in methyl ating an outer edge HDon FIG. 49 FIG. 50 carbon site adjacent to a methylated non- outer edge carbon site, via donating a
  • FIG. 24 illustrates a starting surface of CI 10 carbon. To start building the pyramid structure, new rows are added to the surface beginning with the following reaction sequence:
  • FIG. 25, FIG. 26, FIG. 27, FIG. 28, and FIG. 29, which show the structure at progressive states of completion.
  • FIGS. 20 through 23 provide flow charts of various processes relating to the invention. Note that these flow charts provide only an exemplary embodiment and are in no way intended to limit the invention. Many variations on these processes are possible, and even without changing the steps involved, one might change the decision logic or loop through some processes more than once. For example, to optimally design a workpiece for
  • manufacturability (20-2) may require an iterative process where the workpiece design is revised based on the outcome of subsequent steps or processes, such as the reaction design process described in FIG. 21.
  • This step is similar to that for any traditionally-manufactured product in that product requirements must be defined before the product can be designed from an engineering perspective.
  • Step (20-2) Design Workpiece for Manufacturability also has an analog in traditional manufacturing.
  • the product must be designed with the limitations of the manufacturing process in mind. In the case of mechanosynthesis, this means that a device should be designed with elements and geometries whose properties are understood, and for which tips and reaction sequences have been, or can be, designed.
  • step (20-3) is to "Specify Atomic
  • This step may also include determining bonding structure, as this step can be informative although technically redundant since the bonding structure may be fully specified via the atomic coordinates. This may be done in any molecular modeling or computational chemistry software with the appropriate capabilities, such as GROMACS, LAMMPS or NAMD.
  • Step (20-4) "Determine Reaction Reliability Requirements" involves performing an impact analysis of potential defects and the resultant establishment of reaction reliability requirements.
  • the goal of mechanosynthesis is the production of atomically-precise products, unintended reactions can occur at frequencies which depend on factors including the chemical reactions being used, the tip design, the reaction trajectory, equipment capabilities and temperature.
  • For each reaction one could analyze the most likely pathological side reactions that might occur and their impact upon the finished workpiece. For example, one could determine the impact of a feedstock atom failing to transfer, a feedstock atom bonding to a workpiece atom adjacent to the intended position, or the workpiece undergoing an unintended rearrangement.
  • the workpiece could be simulated with each potential defect, or more general heuristics or functional testing could be used to determine the likely impact of possible errors in the workpiece.
  • FIG. 21 begins with step (21-1) "Determine Order of Reactions, Reaction
  • Each atom as specified in the atomic coordinates of the workpiece, generally (but not necessarily since, for example, one could use dimers or larger molecules as feedstock) requires that a particular reaction be performed on the workpiece to deposit that atom. Abstraction reactions may also be required, as may be reactions which alter the bonding structure of the workpiece without adding or subtracting any atoms.
  • reaction sequence may be simulated to determine if it works correctly (21-2).
  • the same simulations can test reaction parameters including which tip to use, what temperature is required, and what trajectory a tip will follow. As has been previously noted, lower temperatures will favor accuracy, and unless steric issues make it obvious that a different approach is required, frequently the coaxial trajectory will enable successful reaction completion.
  • reaction reliabilities can be calculated (for example, by energy barrier calculations or Monte Carlo simulations).
  • (21-6) is a determination as to whether the proposed reaction reliabilities meet production quality needs, and, if the answer to (21-6) is no, (21-7) where requirements are reviewed to see if the build sequence restrictions can be relaxed since they were not met. From (21-7) if the answer is yes, a new iteration is started at (20-4) to determine revised reaction reliability requirements. If the answer to (21-7) is no, alternate reactions, reaction order, reaction trajectories, or reaction conditions can be simulated (21-1) to find a revised build sequence that meets the reaction reliability requirements. If the answer to (21-6) is yes, the process continues in Figure 22, step (22-1).
  • FIG. 22 is the Mechanosynthetic Reaction Process. Starting at (22-1) "Perform
  • Mechanosynthetic Reactions the reactions determined in the build sequence are carried out using SPM/AFM-like equipment, or other suitable equipment.
  • This step involves, whether manually or in a computer-controlled manner, using a positionally-controlled tip to perform each mechanosynthetic reaction in the build sequence. This means picking up a feedstock atom from a presentation surface (or potentially a gaseous or liquid source of feedstock) and bonding it to the workpiece, or removing an atom from the workpiece, or changing the bonding structure of the workpiece without adding or removing an atom.
  • This step would also encompass other reactions, including reactions not involving the workpiece, such as tip refresh or pre-reaction feedstock manipulation as may be necessary.
  • Step (22-2) is a decision point. If testing is not required, a decision point is reached (22-3) which depends on whether all reactions in the build sequence have been completed. If not, reactions are repeated until the answer is yes, at which point the workpiece is complete. If testing is required, the process continues in Figure 23, starting with step (23- 1).
  • testing may done by, for example, scanning the surface of a workpiece using AFM or SPM-like techniques and checking to see that the expected structure is present. If no errors are found in (23-2), the process continues at (22-3). If an error is present at (23-2), a decision must be made in (23-3) as to whether the error is ignorable (e.g., not an error that would prevent the workpiece from functioning). If it is ignorable, the process again continues with (22-3), although the build sequence may require adjustment if key atoms were moved as a result of the error (not depicted). If the error is not ignorable, it must be determined if the error can be fixed (23-4).

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Nanotechnology (AREA)
  • Manufacturing & Machinery (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)

Abstract

L'invention concerne des trajectoires de mécanosynthèse, lesquelles sont approximativement coaxiales et s'avèrent être utiles dans un large éventail de réactions de mécanosynthèse quelle que soit la nature de la pointe ou de la charge de départ transférée.
PCT/US2013/028415 2013-02-28 2013-02-28 Trajectoires de mécanosynthèse WO2014133530A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/US2013/028415 WO2014133530A1 (fr) 2013-02-28 2013-02-28 Trajectoires de mécanosynthèse

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US2013/028415 WO2014133530A1 (fr) 2013-02-28 2013-02-28 Trajectoires de mécanosynthèse

Publications (1)

Publication Number Publication Date
WO2014133530A1 true WO2014133530A1 (fr) 2014-09-04

Family

ID=51428647

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2013/028415 WO2014133530A1 (fr) 2013-02-28 2013-02-28 Trajectoires de mécanosynthèse

Country Status (1)

Country Link
WO (1) WO2014133530A1 (fr)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5832783A (en) * 1996-10-22 1998-11-10 Sheldon/Van Someren Inc. Three-axis machine structure
US5852298A (en) * 1995-03-30 1998-12-22 Ebara Corporation Micro-processing apparatus and method therefor
US6552339B1 (en) * 1997-10-29 2003-04-22 International Business Machines Corporation Micro goniometer for scanning probe microscopy
US20090056802A1 (en) * 2007-02-16 2009-03-05 Eli Michael Rabani Practical method and means for mechanosynthesis and assembly of precise nanostructures and materials including diamond, programmable systems for performing same; devices and systems produced thereby, and applications thereof
US20090093659A1 (en) * 2007-09-07 2009-04-09 Freitas Jr Robert A Positional Diamondoid Mechanosynthesis
US7687146B1 (en) * 2004-02-11 2010-03-30 Zyvex Labs, Llc Simple tool for positional diamond mechanosynthesis, and its method of manufacture

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5852298A (en) * 1995-03-30 1998-12-22 Ebara Corporation Micro-processing apparatus and method therefor
US5832783A (en) * 1996-10-22 1998-11-10 Sheldon/Van Someren Inc. Three-axis machine structure
US6552339B1 (en) * 1997-10-29 2003-04-22 International Business Machines Corporation Micro goniometer for scanning probe microscopy
US7687146B1 (en) * 2004-02-11 2010-03-30 Zyvex Labs, Llc Simple tool for positional diamond mechanosynthesis, and its method of manufacture
US20090056802A1 (en) * 2007-02-16 2009-03-05 Eli Michael Rabani Practical method and means for mechanosynthesis and assembly of precise nanostructures and materials including diamond, programmable systems for performing same; devices and systems produced thereby, and applications thereof
US20090093659A1 (en) * 2007-09-07 2009-04-09 Freitas Jr Robert A Positional Diamondoid Mechanosynthesis

Similar Documents

Publication Publication Date Title
US10138172B2 (en) Methods, systems and workpieces using mechanosynthesis
US11155461B2 (en) Atomically-precise products and methods and systems for manufacturing the same
US9244097B1 (en) Mechanosynthetic tools for a atomic-scale fabrication
US9676677B2 (en) Build sequences for mechanosynthesis
US8276211B1 (en) Positional diamondoid mechanosynthesis
Herman Tip-based nanofabrication as a rapid prototyping tool for quantum science and technology
US10309985B2 (en) Build sequences for mechanosynthesis
US20130184461A1 (en) Mechanosynthesis Trajectories
US11592463B2 (en) Systems and methods for mechanosynthesis
US11148944B2 (en) Systems and methods for mechanosynthesis
Hines et al. Growth and mechanics of heterogeneous, 3D carbon nanotube forest microstructures formed by sequential selective-area synthesis
CA3078356C (fr) Amorcage et synthese de pointes de mecanosynthese
WO2014133530A1 (fr) Trajectoires de mécanosynthèse
WO2014133531A1 (fr) Procédés, systèmes et pièces faisant appel à la mécanosynthèse
WO2014133532A1 (fr) Séquences de création pour mécanosynthèse
US20130178626A1 (en) Bootstrapping and Synthesis of Mechanosynthesis Tips
Penev et al. Mechanisms and theoretical simulations of the catalytic growth of nanocarbons
Freitas Diamondoid Mechanosynthesis for Tip-Based Nanofabrication
Farmer Modeling and Simulation of Carbon Nanotube Growth.

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 13876597

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 13876597

Country of ref document: EP

Kind code of ref document: A1