EP3245157A1 - Method for synthesizing carbon materials from carbon agglomerates containing carbine/carbynoid chains - Google Patents

Abstract

The invention relates to: - a method for synthesizing carbon agglomerates containing metastable carbyne/carbynoid chains; - a method for synthesizing carbon or carbon compound allotropes from said agglomerates containing metastable carbyne/carbynoid chains; and - the uses of said methods. The method for synthesizing carbon agglomerates containing metastable carbyne/carbynoid chains includes the following steps: a) forming carbon vapor precursors, containing carbine/carbynoid chains, by decomposing a carbon gas selected from among CH₄, C₂H₂, C₂H₄, gaseous toluene, and benzene in the form of vapors at a temperature T such that 1 500°C_<T < 3 000°C; and b) condensing the carbon vapor precursors, obtained in Step a), on the surface of a substrate, the temperature Ts of which is less than the temperature T. The invention is particularly of use in the field of electronics.

Description

 PROCESS FOR THE SYNTHESIS OF CARBON MATERIALS FROM CARBONATED AGGLOMERATES CONTAINING C ARB YNES / C ARB YN OID S

The invention relates to a process for the synthesis of carbonaceous agglomerates containing metastable carbyne / carbynoid chains.

 It also relates to a process for synthesizing carbon allotropes or carbon compounds from these agglomerates containing metastable carbyne / carbynoid chains.

 It still relates to the uses of these methods.

Carbyne is an allotrope of carbon that consists of a linear chain of carbonization hybridization sp of chemical structure (-C≡C-) _n or (= C = C =) _n , as a repeating pattern.

 Because of the alternating presence of single and triple bonds, this would be the ultimate member of the polyynes family while having a cumulative electronic structure when formed by sequential double bonds along the chain.

 A carbynoid is a carbyne chain of variable length whose ends are stabilized by various functional groups such as, for example, metals or organometallic complexes or carbon-based compounds of a different hybridization, such as for example a nanographene crystal. .

A polyyne is a carbon-based compound with alternating single and triple bonds, that is (-C≡C-) _n with n> 1.

 The simplest example of polyyne is diacetylene or 1,3-butadiene: H-C≡C-C≡C-H.

A (poly) cumulene is a carbon-based compound having three or more consecutive cumulative double bonds. A member of these cumulinary compounds is butatriene (also called simply cumulene), H ₂ C = C = C = CH ₂ .

A graphyne or graphdiyne is an allotrope of carbon with a plane-sheet structure, one-atom thick, both sp- and sp2-bonded carbon atoms arranged in a crystal lattice. It can be seen as a network of benzene rings connected by acetylenic chains or longer linear acetylenic chains with carbyne bonds. Depending on the content of acetylene (acetylenic) groups, graphyne can be considered to have mixed hybridization sp "with 1 <n <2, different from the hybridization of graphene (pure sp2) and diamond (pure sp3).

 The combination of atoms of a sp3, sp2 and sp hybridization carbon can give rise to a large number of allotropic forms and phases of carbon.

 To date, only carbon-based solids based on all sp3 (diamond) and all sp2 (graphite, fullerene, carbon nanotubes and graphene) hybridization are well known and characterized.

 There are certainly a large number of other possible transitional forms of carbon in which the sp, sp2 and sp3 hybridization bonds coexist in the same solid, still consisting of only carbon atoms (as for example in some forms of carbon). amorphous carbon, carbon black, glassy carbon, coke and soot, etc ...).

 Sp-hybridization-based solids, which appear to be the most difficult to reach members of the various families of carbon allotropes, have been the subject of intense experimental efforts since the last three to four decades.

 These solids are thought to be abundant in interstellar dust clouds where hydrogen is scarce.

 The existence of linear chains of carbon atoms linked by single and triple bonds (polyyne) or double bonds (polycumulene) has been demonstrated in interstellar molecular clouds and could be artificially produced by different chemical routes in which case these linear carbon chains would be stabilized with different molecular complexes at the end of the chains.

 However, to date, to the inventors' knowledge, the effective large-scale production of carbyne or carbynoid chains (radicals) or their use as blocks of elementary molecular constructions for the synthesis of other forms and allotropic phases of carbon, n have never been obtained.

Yet carby chains are considered the most resistant known material. Resistance in tension (the capacity to support a stretching) carbynes surpasses all other known materials and is double that of graphene.

 It has twice the voltage stiffness of graphene and carbon nanotubes and almost three times that of diamond.

 When equipped with molecular handles at its chain ends, it can also be bent to alter its band gap.

 Stretching a carbyne of as little as 10% alters its band gap significantly from 3.2 to 4.4 eV.

 When bent at 90 °, a carbyne then becomes a magnetic semiconductor.

 The unsaturated carbon-sp chain assemblies exhibit a very high reactivity and a tendency to undergo a chain-to-chain cross-linking reaction causing evolution to the sp2 phase or, under certain conditions, to the sp3 phase, which has generated a strong skepticism as to the possibility of assembling sp carbon chains to form pure carbon solids.

 In contrast to their remarkable physical properties, polyyne or polycumulene chains are highly reactive and thus unstable: exposure to oxygen and / or water can completely destroy these species. But they can also react to exposure to light or charged particles.

 The isolated carbon chains could thus be studied only in the gas phase or by means of very low temperature matrix isolation spectroscopy.

 To date, the generally accepted synthetic routes for the generation of sp chains are based on either high pressure and high temperature modification of carbon-based solids (carbon solids) or on chemical strategies aimed at eliminating substituents. of a linear organic molecule to terminate the bare linear carbon skeleton.

Such "chemical" approaches include catalytic dehydropolymerization of acetylene, dehydrohalogenation of chlorinated polyacetylene, an air promoted coupling reaction of dicuivre acetylide, electrochemical reductive carbonization of poly (tetrafluoroethylene), and the like. But these methods generally produce somewhat "separated" or "isolated / protected" carbon chains by a wide variety of reaction byproducts that are used to avoid crosslinking reactions between adjacent carbynoid chains and their decomposition.

 Some researchers have postponed the possibility of producing an amorphous carbon solid that contains significant amounts of carbyne or carbyne-like structures, by supersonic carbon cluster beam deposition (SCBD). in English) at room temperature and in an ultrahigh vacuum environment.

 They have observed that such sp-hybridized linear carbon structures are very unstable under vacuum or during exposure to oxygen: the carbon structure rapidly deteriorates and evolves to form a common form of sp2 amorphous phase carbon, mainly .

 It can thus be supposed that carbynoid and carbyne sp-hybridization carbon aggregates are metastable structures, that is, they are thermodynamically unstable but are, however, in a state which corresponds to a local minimum of energy and therefore appear as kinetically stable because of their very slow reaction rate in the absence of external stimuli.

 These compounds containing carby and / or carbynoid chains are therefore very difficult to highlight non-destructively.

 Indeed, analytical techniques with high energy electron (transmission electron microscopy (TEM), scanning electron microscopy (SEM)) will most likely unfortunately destroy such a material when the observation process is implemented.

 Optical spectroscopy including Raman spectroscopy (at low optical power densities) or low energy electron diffraction / spectroscopy are probably the most appropriate methods.

Thus, it appears from the foregoing that the scientific and technical issues involved in obtaining carbon compounds (carbon-based compounds) containing carbynes and / or carbynoids (hereinafter called carbynes / carbynoids) are very important. in many areas. They can allow the synthesis of carbonaceous material such as carbon nanomaterials, graphene, graphyne graphdiyne, nanotubes, nanoribbons, etc.

 They can also make it possible to synthesize new pharmaceutical molecules based on double and triple carbon-carbon bonds, they could also allow the synthesis of new semiconductor materials, some possessing Dirac points (very high mobility of the carriers etc ...) .

 Thus, the object of the invention is to provide a process for the synthesis of carbon agglomerates and in particular the deposition in the form of layers or films, of such agglomerates:

 i) having a controllable structure (hybridization sp, sp2, sp3 or mixtures of these phases, for example graphene, graphyne, graphdiyne, nanotubes, nanoribbons, nanodiamond, etc.),

 n) directly on the substrate / final support,

 iii) in accordance with the surface of the substrate / support,

 iv) at low temperature (from room temperature), and v) without constraints on the nature of the substrate / support (for example no catalyst).

 This method allows / facilitates:

 (vi) controlled doping of the films obtained and

 vii) can be implemented on a large scale or at least it is compatible with large-scale implementation techniques (eg roll-to-roll).

 For this purpose, the invention proposes a process for the synthesis of carbonaceous agglomerates containing metastable carbyne / carbynoid chains, characterized in that it comprises the following steps:

 a) formation of carbon-containing precursors containing carbyne / carbynoid chains, by decomposition of a carbon gas at a temperature T such that 1500 ° C <T <3000 ° C, and

 b) condensation of the vapor precursors obtained in step a), on the surface of a substrate whose temperature Ts is lower than the temperature T.

In a first embodiment of this method, step a) is a step of forced (locally confined) passage of the carbon gas through at least a metal filament heated to the temperature T in a chemical vapor deposition (CVD) chamber.

 In this case, the filament is made of a material preferably chosen from among tungsten, tantalum, molybdenum and rhenium.

 In a second embodiment of this method, step a) is a step of localized heating by laser irradiation of the carbon gas in a CVD chamber.

In this second mode of implementation, the laser is preferably a CO ₂ infrared laser or an excimer laser (UV).

In all embodiments of this process, the carbonaceous gas is preferably selected from CH ₄ , C ₂ H ₂ , C ₂ H ₄ , toluene gas and benzene gas.

 Also in all modes of implementation of this process, a carrier gas and / or diluent can be injected at the same time as the carbon gas.

 This carrier gas and / or diluent may be argon, helium or neon.

 In this case, the carbonaceous gas may be introduced via a first orifice and the carrier gas and / or diluent introduced separately through another orifice, or the carrier gas and / or diluent may be injected through the same injection orifice as the carbonaceous gas. .

 The introduction of such a carrier gas and / or diluent allows, in particular, to obtain a condensation, and / or a formation, and / or a more homogeneous deposition of the carbonaceous agglomerates.

 The quantity by mass and volume of condensed agglomerates per unit of time can thus be modulated, which is advantageous when these agglomerates are used, as soon as they are formed, to form other carbonaceous compounds: the kinetics necessary for the formation reaction of the The desired carbon compound can thus be respected.

 Also, this process may furthermore comprise, prior to step a), a step a1) of pretreatment of the surface of the substrate on which the carbonaceous agglomerates containing carbyne / carbynoid chains will be condensed.

This step a1) may be a step of pretreating this surface with radical hydrogen generated in situ by decomposition of H ₂ . It may also be a step of depositing on this surface of the substrate an amorphous alumina layer.

 Furthermore, in another embodiment of this method at least this surface of the substrate is fused silica.

 Still in another embodiment of this method, the surface of the substrate can be treated in order to modify its surface tension properties.

 Preferably, for this purpose, the surface is functionalized with silane groups in order to modify its wettability, in particular with respect to carbon.

 The invention also proposes a process for synthesizing carbonaceous materials, characterized in that it comprises a step A) of synthesis, by the process according to the invention described above, of carbonaceous agglomerates comprising metastable carbyne / carbynoid chains followed by a step B) of converting the agglomerates obtained in step A) into the desired carbon material.

 In an advantageous embodiment of this method, step B) is carried out simultaneously with the condensation step b) of step A) and in the same CVD enclosure.

 However, in another advantageous embodiment of this method, step B) is carried out after the condensation step b) of step A), possibly in a separate enclosure.

 Step B) may be a step implemented by the use of a source of photons, electrons or ions, focused to induce a local transformation of the agglomerate stream obtained in step A), during their deposition on the surface of the substrate, in order to manufacture, in a localized manner, the desired carbon material.

 In other words, step B) is carried out by irradiation of the agglomerates obtained in step A, as and when they are deposited on the surface of the substrate with a source of photons, electrons or ions, whereby a localized transformation of the agglomerates into the desired carbonaceous material is obtained.

Step B) may also be a step of heating the agglomerates containing carby chains / carbynoid chains obtained in step b) of step A), at temperature necessary to obtain the transformation of these agglomerates into the desired material.

 Step B) may also be a light irradiation step, preferably by UV radiation, agglomerates containing carbyne / carbynoid chains obtained in step b) of step A).

 The process for synthesizing carbonaceous materials according to the invention may also comprise, in addition, the injection into the CVD chamber of a gas containing a doping element.

 This gas containing a doping element may be a gas containing nitrogen, boron, phosphorus and / or fluorine, this doping element being to be introduced into the carbon compound to be formed.

 The gas containing a doping element can be injected through the same orifice as the starting carbon gas, or through a separate orifice.

 This process can also include, in addition, the injection of hydrogen into the CVD chamber. Hydrogen is injected particularly when it is desired to produce hydrogen radicals which will react with carbynes / carbynoids to form the desired carbon compounds.

 In this case, that is to say when one wants to produce hydrogen radicals, the hydrogen will be injected by the same orifice as the carbon gas, to be decomposed at the same time.

 But, hydrogen can also be introduced through a separate orifice.

 It will be understood that in the process for the synthesis of carbonaceous agglomerates containing carbyne / carbynoid chains, as in the process for the synthesis of carbon compounds according to the invention, when the carrier gas or the gas containing a doping element, or hydrogen, respectively, is introduced through an orifice separate from that through which the carbonaceous feed gas is introduced, it will be possible to heat this gas to a temperature different from that necessary to decompose the carbon gas injected into the other orifice.

This gives great flexibility for the formation of different compounds. The invention also proposes the use of carbonaceous agglomerates containing metastable carbyne / carbynoid chains obtained by the process according to the invention for the synthesis of chemical molecules containing polyeneic and / or polycyclic chains or for the formation of conforming compound-only coatings. of carbon or for the synthesis of graphenes, graphites, nano-diamonds, fullerenes.

 The invention also proposes the use of carbonaceous agglomerates containing metastable carbyne / carbynoid chains obtained by the method according to the invention as semiconductor materials.

 Indeed, carbynes / carbynoids as well as materials containing these types of compounds, can be in themselves semiconductor.

 Irradiation-type processes can further modify the properties of these materials by transforming them into materials with other gap values, or even semi-metals.

 The carbonaceous agglomerates containing metastable carbyne / carbynoid chains obtained by the process according to the invention may also be used for the manufacture of components of electronic devices or for the storage of energy.

 The invention will be better understood and other details, characteristics and advantages thereof will appear more clearly on reading the explanatory description which follows and which is made with reference to the figures in which:

 FIG. 1 schematically represents a first example of a device for implementing the methods of the invention, this device comprising two separate orifices for separate injection of a carbon gas and a carrier gas and / or diluent and in which the gases are heated by two hot filaments,

 FIG. 2 represents a second example of a device for implementing the methods of the invention, this device comprising a single inlet orifice for the injection of a carbonaceous gas and optionally and simultaneously of a carrier gas and or diluent, the gas (s) being heated by a single hot filament,

FIG. 3 represents a third device for implementing the methods of the invention, this device comprising a single inlet orifice for a carbonaceous gas and possibly a carrier gas and / or diluent, the heating of this (FIG. s) gas being obtained by a filament and in which Laval nozzles are placed at the outlet of the heating zone by the filament to accelerate the gas flow,

 FIG. 4 represents a fourth device for implementing the methods of the invention, in which the heating of carbonaceous gas is obtained by laser irradiation, this device comprising a single inlet for a carbonaceous gas and, optionally, a carrier gas and / or diluent, and in which Laval nozzles are placed at the outlet of the heating zone to accelerate the gas flow,

FIG. 5 represents the Raman spectrum of carbon clusters containing metastable carbyne / carbynoid chains according to the invention, and obtained by the process of the invention and by decomposition of CH ₄ at 2100 ° C. and condensation of decomposed gas on a glass substrate maintained at a temperature of 500 ° C,

FIG. 6 represents the Raman spectrum of carbon clusters according to the invention and obtained by the synthesis method of the invention, containing metastable caryne / carbynoid chains by decomposition of CH ₄ at 2 250 ° C. and condensation of the decomposed gas on an Al ₂ O ₃ / SiO ₂ / Si substrate maintained at a temperature of 450 ° C,

 FIG. 7 represents the Raman spectrum of a graphene layer obtained by the process for synthesizing carbonaceous materials according to the invention,

 FIG. 8 represents the Raman spectrum of a graphite layer obtained by the process according to the invention,

 FIG. 9 represents a real-time monitoring of the residual pressure, measured by mass spectroscopy, in an ultrahigh vacuum chamber before and during the implementation of the agglomerate formation process according to the invention implemented, carried out with the device shown in FIG.

 FIG. 10 shows a complete scan of 1 to 100 amu (atomic masses) of the residual compounds present in a UHV chamber during the implementation of the agglomerate formation process of the invention, at the pressures of the zone denoted 9 A in Figure 9,

FIG. 11 represents the Auger spectrum of the agglomerate layer containing metastable carbyne / carbynoid chains obtained by the implementation of the agglomerate formation process of the invention, in an ultrahigh vacuum chamber in the device shown in Figure 3 with an in situ and real-time monitoring over a period of 700 minutes,

 FIG. 12 is a photograph taken during the step of localized deposition of a thin carbon film, in an ultrahigh vacuum chamber, using the device shown in FIG. 3 and with a local transformation, in situ, at room temperature agglomerates containing metastable carbyne / carbynoid chains using a focused electron beam (right-hand photograph) or scanning mode (left-hand photograph). This same beam of electrons, energy and variable intensities can be used to perform a characterization of the layer formed during deposition, for example in imaging mode (SEM or METS) or by Auger spectroscopy or energy losses. electron. These images show the fluorescence spots of the substrate (Si coated with a layer of thermal silica) under the effect of irradiation by the electron beam,

 FIG. 13 is an optical photograph of the layer deposited locally using the device shown in FIG. 3 and with a local transformation, in situ, of agglomerates containing metastable carbyne / carbynoid chains using an electron beam in scan mode. We note the correspondence of the scan pattern shown in FIG. 12 (left-hand photograph) and the morphology of the thin film deposited,

 FIG. 14 shows the Raman spectra of agglomerates containing metastable carbyne / carbynoid chains deposited (and not transformed) around the writing zone by the electron beam in FIGS. 12 and 13,

 FIG. 15 shows the Raman spectrum of the thin layers shown in FIGS. 12 and 13 obtained by a local transformation, in situ, at ambient temperature, of agglomerates containing metastable carbyne / carbynoid chains using an electron beam focused or in scan mode,

 FIG. 16 shows the spectrum of energy losses of the slow electrons during the deposition of a graphite layer carried out in example 5,

FIG. 17 is an illustration of the use of the local transformation, in situ, at ambient temperature, of agglomerates containing carbyne chains / metastable carbynoids by means of an electron beam according to the three basic processes in the microelectronics industry: zone (A) localized deposit of a material (in this case controllable and modifiable properties) using the carbyne / metastable carbynoid chains generated by the device shown in Figure 3; zone (B) destruction / local elimination of this material using the electron beam in the presence of oxygen (pressure 10 ^"6 mbar) without affecting the material in the neighboring zone not exposed to the electron beam, and zone (C) transforming a portion of the deposited material in zone (A) under the effect of a higher dose exposure of the electron beam,

 FIG. 18 shows the Raman spectra of the three layers obtained in zones A, B and C shown in FIG. 17, as well as the Raman spectrum corresponding to the deposition of agglomerates containing non-transformed metastable carbyen / carbynoid chains using electron beam (zone D),

 FIG. 19 shows the Auger spectra and electron energy losses corresponding to the three zones A B and C shown in FIG. 17,

 FIGS. 20 and 21 are illustrations of the use of the localized deposition technique using an electron beam (type (A) of FIG. 17) to deposit a partially graphitized layer, in a manner consistent with FIG. , on Pd electrodes pre-deposited on the Si substrate (degenerate) covered with a thermal silica layer (300nm). This allows the simple manufacture of a back-gate gate-field-effect transistor-type device whose electrical characteristics are shown in FIG. 20. The semiconductor character of the material deposited in a localized manner by means of the electron beam is illustrated by the temperature dependence of the conductivity of the channel and by a persistent photoconduction effect under light exposure as shown in Figure 21.

 Current techniques for meeting one or more of the above criteria (i) to (vii) are chemical vapor deposition (CVD) techniques that produce carbon films (DLC, diamond, graphite / graphene, nanotubes). using vapor precursors in the form of optionally activated hydrocarbon molecules (radicals or ions). However, all these techniques currently require:

at. special substrates for temperature resistance (typically between 500 ° C. and 1000 ° C.) and / or comprising a catalyst, b. some films (eg graphene) often have to be transferred later to the final substrate, and

 vs. if the growth is carried out at low temperature, subsequent recrystallization steps (high temperature annealing may exceed 1500 ° C, or high energy laser annealing) may be employed but they also include important limitations in terms of substrate compatibility and often their effectiveness is low / poorly reproducible.

 However, no CVD technique has so far made it possible to produce and isolate carbyne or carbynoid-rich carbon-rich materials.

 The invention makes use of a paradigm shift: instead of using hydrocarbon molecules / radicals for the CVD growth of various carbon films, agglomerates also called carbyne / carbynoid clusters will be used.

 This implies :

 at. that the carbon film will be formed by condensation of carbyne / carbynoid clusters. The surface properties (wettability / surface tension, presence of defects) will also have a strong effect on the formation of the carbon film,

 b. that the carbon film can be "shaped" in situ, during its construction, as in conventional CVD, for example through the use of radical hydrogen which is known to be very reactive vis-à-vis different phases of carbon and in particular of amorphous carbon (generally supposed to be of sp hybridization),

 vs. that the nature of the carbon film obtained can be further modulated by controlling the nature of the carbyne / carbynoid clusters generated in the gas phase (chain length, type of chain termination), and

 d. that the carbyne / carbynoid clusters can be condensed on a cooled substrate or placed in a cold zone.

The method of the invention then becomes compatible with the use of supports made in the majority of known materials. The resulting film will contain stabilized carbyne / carbynoid chains that can be further "transformed" in a controlled manner in other types of variable hybridization materials.

 Indeed, the carbon-carbon triple bond is a state of "high energy" for carbon. The theoretical stability domain of carbyne is between that of graphite (the most stable phase) and diamond (see below).

 This implies that:

 i. under the effect of a small disturbance of the condensed film (heating, illumination) carbon-carbon bonds of "high energy" will relax to the more stable phase of the graphite. Compositional materials (in terms of carbon hybridization) and variable structures can thus be easily obtained. It is in this case new carbon allotropies which may have very interesting properties for various applications,

 ii. if such a film is subjected to a strong disturbance, for example exposure to a high energy laser beam (excimer or femtosecond lasers) the additional energy provided may induce a switch to the sp3 phase of the carbon and therefore the formation of the (nano) diamond

 Therefore, a first object of the invention is a method for synthesizing carbon-containing clusters (agglomerates containing carbon), these agglomerates containing metastable carbyne / carbynoid chains, which will now be described with reference to FIGS. .

 As can be seen in FIGS. 1 to 4, the deposition of carbonaceous clusters containing carbynes / carbynoids according to the invention is carried out by CVD in a CVD enclosure denoted 12 in FIG. 1, 12 'in FIG. 2, 12 "in FIG. 12 "'in Figure 4, and is on the surface, denoted 1 1 in Figure 1, 1 1' Figure 2, 11" in Figure 3 and 11 "'in Figure 4, a substrate, denoted 1 in Figure 1 2, 1 "in FIG. 3 and 1" in FIG. 4, placed opposite a carbon gas injection tube, denoted by FIG. 1, 9 'in FIG. 2, 9 "in FIG. and 9 '"in FIG.

The CVD enclosure 12, 12 ', 12 "and 12"' comprises a heating resistor, denoted 7, 7 ', 7 "and 7'" in FIGS. 1 to 4 respectively, a transfer chamber denoted by 5 and 5 'respectively in FIGS. 1 and 2, and an apparatus for putting under empty inside the CVD enclosure. This apparatus of evacuation is noted 4 and 4 'respectively in Figures 1 and 2 (not shown in Figures 3 and 4).

 The systems shown in Figures 3 and 4 may also include a transfer chamber (not shown in Figures 3 and 4).

 A thermocouple 3 and 3 'respectively in Figures 1 and 2 (not shown in Figures 3 and 4) allows to control the temperature of the substrate 1, V, 1 ", 1".

The process for synthesizing carbonaceous agglomerates containing metastable carbyns / carbynoids of the invention comprises the formation of carbonaceous vapor precursors containing metastable carbyns / carbynoids by decomposition of a carbonaceous gas (CH _X ) at a temperature T such that 1500 ° C <T <3,000 ° C and the condensation of these precursors vapors on the surface 1 1, 1 1 ', 11 ", 1 1''of a substrate 1, 1', 1", 1 '", the temperature Ts is lower than the temperature T.

 For this, the CVD enclosure 12, 12 ', 12 ", 12"' is equipped with a carbonaceous gas heating means which can be either a hot filament, denoted 6 in FIG. 1, 6 'in FIG. 6 "in FIG. 3, again a device for heating by laser irradiation, denoted 10 in FIG.

The carbonaceous gas may be any carbon-containing gas such as methane (CH ₄ ), acetylene (C ₂ H ₂ ), ethylene (C ₂ H ₄ ), or toluene or benzene in the form of vapors.

 This gas is decomposed locally under the effect of the high temperature obtained by laser irradiation or by forced passage and confined through one or more metal filaments 6, 6 ', 6 ".

 The metal filaments may be tungsten, tantalum, molybdenum or rhenium.

 The vapor precursors of the carbonaceous agglomerates containing carbyen chains / metastable carbynoids are then condensed on the substrate 1, 1 ',

1 ", 1" ', placed in a cooler zone of the CVD enclosure 12, 12', 12 ", 12" '.

When the heating is heating by laser irradiation, the laser used may be a CO ₂ infrared laser or a UV emitting excimer laser. In a particular embodiment of the invention, a gas containing a doping element may also be injected into the CVD chamber.

 This doping element may be nitrogen, boron, phosphorus or fluorine.

 This gas containing the desired doping element can be introduced simultaneously with the carbon gas to be decomposed, mixed with it by the orifice 9, 9 ', 9 ", 9"' or by a separate orifice, denoted 8, 8 ", 8" 'in Figures 1, 3, 4.

 The carbonaceous gas may also be mixed with a carrier gas such as helium.

 Agglomerates of carbonaceous compounds containing metastable carbyne / carbynoid chains deposited on the surface 11, 11 ', 11 ", 11'" of the substrate 1, 1 ', 1 ", 1" which can be used to construct customized 'innovative materials.

 These agglomerates can make it possible to construct, directly on a substrate 1, 1 ', 1 ", 1", any metal, insulating material, plastic, etc. without constraints and in a controllable manner, new and crystalline materials such as example graphene or other materials of graphitic structure, graphyne, or even diamond or nanodiamant.

 Indeed, these carbon clusters containing carby chains / metastable carbynoids can be seen as molecular bricks usable to build countless allotropic forms of carbon, many of which may have unprecedented and unique physicochemical properties.

 This formation of compounds can be carried out continuously, at the same time as the formation of clusters, directly on the substrate 1, 1 ', 1 ", 1" which will then be heated to the appropriate temperature to form the desired compound.

 This heating may be effected by irradiating the flow of clusters settling on the surface 11, 11 ', 11' 'of the substrate 1, 1', 1 ", 1 '", with UV radiation or with a laser or a source of photons or electrons or ions.

Optionally pressure may also be applied around the substrate 1, 1 ', 1 ", 1"". But the agglomerates formed by the process of the invention may also be used to synthesize new compounds after being taken out of the CVD chamber 12, 12 ', 12 ", 12'" and placed in another chamber where the still Temperature conditions (obtained as previously by irradiation with UV radiation or with a laser or a source of photons or electrons or ions) and pressure appropriate to obtain the desired compound will be applied.

 To favor the formation of certain crystalline structures, the method of the invention makes it possible to choose the nature of the substrate 1, 1 ', 1 ", 1".

 Thus, at least the surface 11, 11 ", 11", 11 "of the substrate 1, 1", 1 ", 1" "can be made of fused silica, to promote the formation of agglomerates and layers of such For example, highly crystalline agglomerates are graphene with the inclusion of carbyne ring chains.

 But it will also be possible, before decomposing the carbonaceous gas in the CVD chamber 12, 12 ', 12 ", 12"', to treat the surface 11, 1 1 ', 1 1 ", 1 1"' of the substrate 1, 1 For example, by depositing an amorphous alumina layer to promote the formation of crystalline high quality graphene layers.

 In this case, to obtain graphene, a temperature of 800 ° C. will be used as the temperature of the substrate, and the filaments 6, 6 ', 6 ", preferably of tungsten, will be heated to 2100 ° C., and a stream containing the gas. For example, the carbonaceous gas will be methane and the flow of gas injected will consist of 10% by volume of methane and 90% by volume of hydrogen for a total pressure of 100 mbar.

 In this example where the deposition is performed on the alumina, the hydrogen serves to select the strongly graphitic phase during growth and to largely eliminate the other types of carbon.

 It is the phase transformation that alumina undergoes (crystallization) at this deposition temperature which is used to obtain the high crystalline quality of graphene.

But it will also be possible to control the nature of the clusters deposited on the surface 1 1, 1 1 ', 1 1 ", 11"' of the substrate 1, 1 ', 1 ", 1"' by selective etching of certain phases of the carbon (sp, sp2 or sp3) by injecting, at the same time as the carbon gas to be decomposed, a flow of hydrogen. This flow hydrogen generates, at the temperatures obtained by the filaments 6, 6 ', 6 "or by the laser 10, a highly reactive (radical) hydrogen flux.This highly reactive hydrogen flux (radical hydrogen) is used to control the nature of the carbonaceous clusters containing carbyne chains, synthesized by the process of the invention, for modifying the proportion of sp, sp2 or sp3 phase in addition to the other control parameters.

 For example, the hydrogen can be injected through the hot filaments 6, 6 ', 6 "or the plasma created by the laser 10, mixed with the carbon gas, that is to say through the orifice 9, 9 ', 9 "or separately therefrom (as shown in Figure 2, where it is introduced through the separate orifice 8, 8", 8 "').

 Thus, another subject of the invention is a method for synthesizing carbonaceous compounds which comprises a step A) of formation of a stream of clusters or clusters (not in flow form) containing carby chains. metastable carbynoids according to the method of the invention described above and a step B) of transforming these clusters into the desired carbon material (the desired carbon compounds).

 These carbon compounds can be allotropes of carbon such as carbon nanomaterials (such as graphene, graphyne, graphdyyne, carbon nanotubes, nanorubans (nanolaces in English) carbon) from the clusters formed by the process synthesis of carbon-containing clusters (agglomerates) containing carbyne chains / metastable carbynoids of the invention.

 It may also be other carbon compounds containing elements other than carbon.

 In particular it will be possible to synthesize films having a controlled structure, directly on the final substrate, in a manner consistent with the surface of this substrate, at low temperature and without constraints on the nature of the substrate.

 The films obtained can be doped and are compatible with a large scale production.

The methods of the invention can be used for the synthesis of molecules involving, for example, polyene chains, optionally cyclic, new or inaccessible until now, these molecules can be used in particular in the pharmaceutical field. The methods of the invention may also allow the production of conformal coatings on various materials: it suffices to collect / condense, for example, the carbonaceous clusters containing carbyne / carbynoid chains metastable on the object of interest, then to expose them to a UV radiation to achieve a controlled transformation of these materials into a material composed solely of carbon. This carbon-only material is a biocompatible material with exceptional mechanical and septic properties.

 The methods of the invention may also be used to synthesize carbon in various forms such as graphite, graphene, (nano) diamond or carbyne linear chains possess exceptional properties.

 Combinations of such materials can also be synthesized to synthesize new materials with exceptional properties with many potential applications such as functional coating, reinforcement.

 Moreover, since the crystalline forms of carbon possess exceptional properties (sp3-diamond semi-conductor with very large gap, sp2-graphene semi-metal with very high mobility, sp-carbyne semi-metal (cumulene) or semi-conductor ( polyyne) magnetic), thanks to the method of the invention, one can combine "at will" these various materials to produce new hybrid materials to obtain new semiconductor materials, conductive and / or insulating.

 The methods of the invention also allow the synthesis of the desired compounds directly on the substrate / support of interest without constraints of temperature, composition or need of a transfer on the desired substrate.

 The methods of the invention make it possible to obtain novel semiconductor materials, some of which have Dirac points, that is to say having a very high mobility of the carriers.

The materials obtained by the methods of the invention can be used for the manufacture of components of electronic devices, sensors, or optoelectronic devices including photovoltaic ^devices' c, and flexible electronic devices. However, the materials obtained by the processes of the invention may also be used for storing energy. Indeed, graphite can store a Li ion for 6 C atoms. A carbyne / carbynoid chain does not have this limitation. A hybrid with a high concentration of carby chains provides a much higher capacity for insertion of Li ions while keeping the exceptional properties of graphite in terms of stability in cycling.

 In order to better understand the invention, will now be described, by way of illustration and not limitation, several examples of implementation.

 Example 1 Synthesis of Carbon Clusters by the Process of the Invention

CH ₄ was decomposed by forced passage through hot tungsten filaments at a temperature of 2100 ° C in the CVD chamber 12 shown in FIG.

 The gases thus decomposed are entrained towards the surface 11 of the substrate 1 which is maintained at 500 ° C. by the heating means, denoted 7, of the CVD enclosure 12.

 The CVD 12 enclosure was under a pressure of 100mbar.

 The substrate 1 was made of glass.

A layer of carbonaceous clusters containing metastable carbyne / carbynoid chains was obtained by condensation on the glass substrate 1 of the gases resulting from the decomposition of CH ₄ .

 The Raman spectrum of this layer is shown in FIG.

 The difficulty in obtaining pure carbyne / carbynoid samples makes reference Raman spectra difficult to find in the literature. In addition, theoretical calculations show that polyyne bonds and cumulenes have similar Raman spectra. It is generally accepted that the sp bonds of carbon have, depending on the length of the chain of atoms of

1 1 carbon, Raman bands in the region from 1750 cm ^" to more than 3000cm ^" . It is also accepted to use a semi-empirical formula that relates the position of the characteristic Raman bands to the number of carbon atom pairs with sp (triple bond or double bond) bonds. This formula proposed by Kastner et al. (J. Macromolecules 1995, 28, 344-353; L. Kavan and J. Kastner Carbyne and Carbynoiuds 1999 page 342-356) is:

Freq (in cm ^-5 ) = 1750 + 3980 / N

 Where N = number of carbon atom pairs with sp-type bonds.

 Therefore the Raman spectrum obtained for the layer obtained in this example, and shown in Figure 5, confirms the presence of carbynes / carbynoids in this layer.

 Example 2

The procedure was as in Example 1 and in the same CVD chamber 12. But the substrate was a substrate comprising an alumina layer (Al ₂ O ₃ ) (30 nm) deposited on an SiO ₂ surface-oxidized silicon substrate ( 300nm) / If maintained at a temperature of 450 ° C. The decomposition of CH ₄ gas was carried out at 2250 ° C.

The Raman spectrum of the condensed layer obtained is shown in FIG. 6. The presence of numerous bands attributable to carbynes / carbynoids, with even very long chains formed (bands around 1780 cm ⁴ ) present in the deposited layer, which contains elsewhere also a graphitic material (sp2 carbon) whose characteristic bands D and G are intense. The crystalline nature of the material is also confirmed by the presence of second-order (2x) or even third-order tapes.

Example 3 Synthesis of Graphene by the Process for Synthesis of Carbonaceous Materials According to the Invention

 a) Synthesis of carbon clusters containing metastable carby chains.

The procedure was as in Example 1 except that, in addition, hydrogen was also introduced through the orifice 8 of the CVD chamber shown in FIG. 1 and the substrate was an A1 ₂ O ₃ substrate. / SiO ₂ / Si.

b) Graphene synthesis. As the decomposition of the CH ₄ and the condensation of the gas resulting from this decomposition on the substrate 1 maintained at a temperature of 800 ° C., a graphene layer was formed.

 The graphene layer thus obtained was analyzed by Raman spectroscopy.

 The Raman spectrum obtained is represented in FIG.

 It will be noted from this FIG. 7 that, with respect to the preceding example, the material obtained in the present example is mainly graphene, as suggested by the presence of the G and 2D intense and fine bands respectively. From the magnification x10 of this figure it can be seen that bands L1, L2 and L3 characteristic of the linear chains of carbon sp are always present although less intense. It is therefore a hybrid material consisting of islets of graphene linked by carbyne bridges.

Example 4: Formation of a graphite layer by the process according to the invention.

The procedure was as in Example 1, that is to say by decomposition of CH ₄ by forced passage through hot tungsten filaments at a temperature of 2100 ° C. and condensation of the gases thus decomposed on a substrate in glass.

 But in this example, the substrate 1 was maintained at a temperature of 50 ° C.

 The Raman spectrum of the agglomerates layer containing metastable carboyl / carbynoid chains thus obtained is shown in FIG. 8.

We see in this figure that the layer obtained contains mainly carbynes / carbynoids of varying lengths as demonstrated by the presence of numerous characteristic bands between 1750cm ^-1 and 3000cm ^-1 . The material contains a very low proportion of graphitic carbon (bands D and G at 1350 and 1600 cm ^-1 ), probably resulting from the cross-linking reaction of carby chains.

The substrate coated with this layer was then subjected to exposure to the light beam of an arc lamp (Xe) delivering 300cd (3000 lumens) focused on about 5cm2, and that also emits (> 10%) of light in the UV and TIR (-10%) range.

 The Raman spectrum of the layer thus transformed is represented in FIG. 8.

 It can be seen from FIG. 8 that under the effect of the luminous flux of cross-linking reactions of the carby chains, the material has evolved to a material with a high proportion of graphitic carbon, as indicated by the intensification of characteristic bands G and D.

Example 5 Formation of a graphene / carbyne layer by the method according to the invention.

The procedure was as in Example 1, that is to say by decomposition of CH ₄ by forced passage through hot filaments at a temperature of 2100 ° C. and condensation of the gases thus decomposed on a covered Si substrate. a silica layer of 100 nm,

 But in this example, the substrate 1 was kept at room temperature.

The deposition was carried out in an ultrahigh vacuum chamber on which the source of generation of the carbyne / carbynoid clusters described in FIG. 3 was mounted. The pressure P i at the inlet of the orifice 9 'was of a few tens of mbar. The output pressure (UHV chamber or the substrate is placed) was 4xl0 ^"7 mbar. The estimated gas flow rate was 0,05sccm. Under these conditions the number of injected carbon atoms should allow (assuming use 100% carbon from the injected CH ₄ ) to deposit the equivalent of a single layer of carbon on the surface of the sample (25x25 mm) every 30 minutes or so.

The Auger spectrum of the agglomerates layer containing metastable carbyne / carbynoid chains thus obtained is shown in FIG. 11 with a follow-up in situ and in real time over a period of 700 minutes. The thickness of possible material to be probed by this technique, under the experimental conditions used (electron beams incident very close to the surface of the sample) is limited to about 1-2 nm. From FIG. 11 we can see the formation of a carbon deposit which reaches, towards the end of the deposit (very strong attenuation of the Si and O signals corresponding to the substrate), a thickness of the order of one nanometer.

 The residual pressure in the ultrahigh vacuum chamber was followed, for the duration of the deposition, by mass spectroscopy as shown in FIGS. 9 and 10.

 As can be seen, the flow of methane injected into the carbyne / carbynoid clusters generating source described in FIG. 3 undergoes more than 99% dissociation, the resultant detectable products being mainly recombined hydrogen (correlated mass spectrum with the total pressure in the enclosure). The carbon resulting from this dissociation forms clusters of carbynes / carbynoids of large mass, outside the range of detection of the spectrometer which we use.

 It is possible to use this stream of carbyne / carbynoid clusters in order to condense them on a substrate as in the previous examples. FIG. 14 shows the Raman spectrum of the layer resulting from this condensation on a silica-coated Si substrate (100 nm), the deposition being carried out at ambient temperature. The presence of carbynes / carbynoids is noted. Compared to the previous example (and FIG. 8), it is noted that the smallest thickness of material deposited does not lead to crosslinking reactions, since no graphitic type signal (bands G and D) is present in the spectrum. .

 Moreover, during the deposition, it is possible to use a concentrated source of photons, electrons or ions, to induce a local transformation of the flow of the clusters of carbynes / carbynoids during deposition, in order to manufacture in a localized manner, the desired carbonaceous material.

An example in which an electron beam (1 to 5 keV) is used is shown in Figure 12 on which the fluorescence spot of the focused beam (approximately 1.5 mm in diameter) is marked on the right, while on the left, the fluorescence spot of the electron beam is seen sweeping a surface (rhombus) of about 0.7 cm ² .

In the region swept by the electron beam during deposition using the flow of carbyne / carbynoid clusters, localized deposition is noted. ambient temperature, of a material having the same morphology as the scanning area of the electron beam, as illustrated in FIG. 13.

 The Raman analysis shown in FIG. 15 (average over 30 random points within the diamond) of the irradiated zone shows the formation at ambient temperature of a crystalline and graphitic film with carbyne chain inclusions. The transformation is only located at the writing area with the electron beam. This is illustrated in Figure 14 which shows the Raman spectrum (average over 30 random points in a circle of about 1 cm around and outside the diamond) of the deposit outside the writing area. The spectrum shows the presence of unprocessed carbyne / carbynoid clusters.

 This is of extreme importance for the microelectronic industry because it will allow construction (depending on the type of carbyne / carbynoid clusters, presence or absence of dopants, temperature, irradiation dose and electron energy) at will, in a localized way. (with the precision of the electron beams in current electron beam machines that reach the nanometer) and even at room temperature, on all types of media in different types of carbon materials with the desired properties. Therefore, one can practically "write" an entire electronic circuit, with extreme flexibility of its design and its features, in a vacuum system, which can replace a clean room, on any support, at room temperature. Moreover, it is possible to control in situ and in real time and at each writing point, the nature of the material formed. The example is provided both by the analyzes shown in FIG. 11 and by the analyzes shown in FIG. 16, which represents the energy loss spectrum of the electrons (beam used for writing in FIG. 12) showing the formation of a layer containing carbon of sp and sp2 type.

 Example 6 Formation and transformation of a graphene / carbyne layer by the method according to the invention.

The procedure was as in Example 5, that is to say by decomposition of C¾ by forced passage through hot filaments at a temperature of 2250 ° C. and condensation of the gases thus decomposed on a Si substrate covered with a silica layer of 100 nm and maintained at room temperature. The deposition was carried out in an ultrahigh vacuum chamber on which the source of generation of the carbyne / carbynoid clusters described in FIG. 3 was mounted. The pressure P1 at the inlet of the orifice 9 'was 100 mbar. The outlet pressure (ultrahigh vacuum chamber or substrate is placed) was 5x10 ^-6 mbar. The gas flow rate was 1 sccm.

 During deposition, an electron source was used to induce a local transformation of the flow of carbyne / carbynoid clusters during deposition, in order to locally produce the desired carbonaceous material.

Firstly, the electron beam (2.5 keV, ΙΟμΑ) is used as illustrated in FIG. 17A (on which the spot of fluorescence of the focused beam is marked on the right) to scan a surface (diamond) of approximately 0. , 7 cm ² as in Example 5, for 30 min.

In a second step, the generation source of the carbyne / carbynoid clusters described in FIG. 3 is stopped. A flow of molecular oxygen (0.1 sccm, pressure in the chamber 5 × ¹⁰ -7 mbar) is injected into the chamber through the orifice 8 ', in which case the electron beam (2.5 keV, 10μΑ) is used as illustrated in FIG. 17B in focused mode (approx. 1.5 mm in diameter) in the center of the deposition area (scanning) carried out previously.

In a third step, the injection of the oxygen flow is stopped. Under ultra-high vacuum this time (pressure in the chamber 10 ^-10 mbar) the electron beam (2.5 keV, 10 μΑ) is used as illustrated in FIG. 17C (on which, on the right, the beam fluorescence spot is noted. focused) to scan a surface (diamond) of about 0.3 cm ² always centered with respect to the first area of the deposition performed previously.

 Figure 17 shows the photographs of the surface of the samples at the end of these treatments and left the deposit chamber. We note the presence of three zones (difference of contrast) of deposit with different apparent characteristics and whose morphology perfectly follows the three types of writing / scanning by the electron beam.

Figure 18 shows the Raman spectra corresponding to the three zones A, B and C of Figure 17 (corresponding to the three types of deposition performed). Also shown is the Raman spectrum corresponding to the agglomerate deposition containing metastable cary chains / carbynoids not transformed with the electron beam (outside the writing areas) and which is similar to the results obtained in Example 5.

 In the region A corresponding to the region swept by the electron beam while the carbyne / carbynoid clusters were being deposited (operation of the carbyne / carbynoid clusters generating source described in FIG. 3), the formation of a material identical to that obtained in Example 5 (Figure 8) and which contains islands of graphene bound by carby bridges.

 In the region B corresponding to the region exposed to the focused electron beam and in the presence of a flow of oxygen, there is the virtual disappearance of the graphene / carbyne bands sign of the local destruction of the previously deposited material. It is important to note that this destruction is localized only in the electron beam irradiated region because, as shown by the spectra on the remainder of the surface (region A and non-swept region), the carbonaceous not been affected.

 The spectrum of the region C corresponding to the region scanned by the electron beam, under ultra-high vacuum, superimposed on the deposition zone A, shows that it is possible to continue the transformation (in this case graphitization) of the layer previously deposited in the electron-beam-swept region while carbyne / carbynoid clusters were being deposited (operation of the carbyne / carbynoid clusters generation source described in Figure 3). This deposit still contained a large fraction of carbyne / carbynoid clusters. As demonstrated by Raman spectra, the characteristic bands of carbyne / carbynoid clusters are strongly attenuated in region C in favor of an intensification of the characteristic G, D and 2D bands of graphene / graphite.

These three examples are a very good illustration of the use of the local transformation, in situ, at ambient temperature, of agglomerates containing carbyne chains / carbynoids metastable using an electron beam according to the three methods of base in the microelectronics industry: zone (A) localized deposition of a material (in this case with controllable and modifiable properties) using the carbyne / metastable carbynoid chains generated by the device shown in figure 3; zone (B) destruction / local elimination of this material using the electron beam in the presence of oxygen (pressure 10 ^"6 mbar) without affecting the material in the neighboring zone not exposed to the electron beam; (C) transforming a portion of the deposited material into zone (A) under the effect of higher electron beam exposure.

 As in Example 5, the electron beam can be used (by performing Auger electron spectroscopy or electron energy losses) in situ and in real time to obtain information about the (local) nature material being deposited or processed.

 Figure 19 shows the Auger spectra and electron energy loss corresponding to the three processes used in the three corresponding zones, AB and C in Figure 17. These spectra, in addition to Raman analysis, confirm the local destruction of the deposited layer (zone B) and also the localized (accented graphitization) transformation of this layer (zone C).

Example 7 Formation and transformation of a graphene / carbyne layer by the method according to the invention and manufacture of a device (photo) field effect transistor type.

The procedure was as in Example 6, that is to say by decomposition of CH ₄ by forced passage through hot filaments at a temperature of 2250 ° C. and condensation of the gases thus decomposed on a substrate maintained at room temperature. ambient temperature. The deposition was carried out in an ultrahigh vacuum chamber on which the source of generation of the carbyne / carbynoid clusters described in FIG. 3 was mounted. The pressure P1 at the inlet of the orifice 9 'was 100 mbar. The outlet pressure (ultrahigh vacuum or substrate is placed) was 5x10 ^-6 mbar. The gas flow rate was 1 sccm. During the deposition, we used an electron source (2.5 keV, 10μΑ) to scan an area of about 0.7 cm ² to induce local transformation of the flow of carbyne / carbynoid clusters during deposition. in order to locally produce, and conformably, the desired carbonaceous material.

The substrate used was in Si (degenerate) covered with a layer of thermal silica (300nm), On its surface were previously deposited (shadow masking technique) a set of electrodes Pd that we can note in Figure 20 (top). The carbonaceous layer conformally deposited on this set of electrodes has been used as a conduction channel in a rear-sided gate field effect transistor type device whose electrical characteristics are shown in FIGS. 20 and 21.

 The semiconductor nature of the material deposited in a localized manner by means of the electron beam is also illustrated in FIG. 21 by the dependence of the temperature of the conductivity of the channel and by a persistent photoconduction effect under exposure to light ( commercial diodes at 454nm, 650nm and a Xe arc broad-spectrum projection lamp). It should be noted that this persistent photoconduction effect is rarely (and only very recently: Nature Nanotechnology 8, 826-830 (2013); Nano Lett, 2011, 11 (11), pp 4682-4687) obtained at room temperature.

Claims

1. Process for the synthesis of carbonaceous agglomerates containing carby chains / metastable carbynoids, characterized in that it comprises the following steps:

a) formation of carbonaceous precursors containing in carby chains / carbynoid chains by decomposition of a carbon gas, selected from CH ₄ , C ₂ H ₂ , C ₂ H ₄ , toluene gas and benzene in the form of vapors, at a temperature of temperature T such that 1500 ° C <T <3000 ° C,

 b) condensation of the carbonaceous precursors vapors obtained in step a), on the surface (1 1, 1 1 ', 1 1 ", 1 1" ") of a substrate (1, 1', 1 '' 1 ') ") whose temperature Ts is lower than the temperature T.

 2. Method according to claim 1, characterized in that step a) is a step of forced passage of the carbon gas through at least one metal filament (6, 6 ', 6 "), preferably of a material selected from tungsten, tantalum, molybdenum and rhenium, heated to temperature T in an enclosure (12, 12 ', 12 ").

3. Method according to claim 1, characterized in that step a) is a step of heating by laser irradiation (10), preferably a CO ₂ infrared laser or an excimer laser (UV), carbon gas in a speaker (12 '").

 4. Method according to any one of the preceding claims, characterized in that, in addition, a carrier gas and / or diluent is injected at the same time as the carbon gas via a separate orifice (8) or by the same orifice of injection (9 \ 9 ", 9 '") as the carbon gas.

 5. Method according to any one of the preceding claims, characterized in that it comprises, in addition, before step a) a pretreatment step al) of the surface (1 1, 11 ', 11 ", 11" ') of the substrate (1, 1', 1 ", 1 '").

6. Method according to claim 5, characterized in that the pretreatment step a1) is a deposition step on the surface (1 1, 1 1 1 1 ", 1 1"') of the substrate (1, 1', 1 ", 1 '") of an amorphous alumina layer or a step of functionalizing the surface (1 1, 1 1', 11 ", 1 1"') of the substrate (1, 1', 1 ", 1 ""), preferably with silane groups.

7. Method according to any one of the preceding claims, characterized in that at least the surface (1 1, 1 1 ', 1 1 ", 1 1" ") of the substrate (1, 1', 1", 1 '') ") is fused silica.

 8. Process for synthesizing carbonaceous materials, characterized in that it comprises a step A) for the synthesis of carbonaceous agglomerates comprising metastable caryne / carbynoid chains by the process according to any one of Claims 1 to 7, followed by a step B) of transforming the agglomerates obtained in step A) into the desired carbon material, this step B) being carried out in a separate enclosure.

 9. Process according to claim 8, characterized in that step B) is carried out by irradiation of the agglomerates obtained in step A, as and when they are deposited on the surface (1.11%). , 11 ", 1 1" ') of the substrate (Ι, 1', 1 ", 1 '") with a source of photons, electrons or ions, whereby a localized transformation of the agglomerates into the desired carbon material.

 10. The method of claim 8 or 9, characterized in that step B) is carried out by heating the agglomerates containing carby chains / carbynoids obtained in step b) of step A), at room temperature. necessary to obtain the transformation of these agglomerates into the desired material.

 1 1. Process according to claim 8 or 9, characterized in that step B) is a step of irradiation with UV radiation agglomerates containing carby chains / carbynoids obtained in step b) of step A ).

 12. Method according to any one of claims 8 to 1 1, characterized in that step a) of step A) further comprises the injection into the chamber (12, 12 ', 12 ", 12 "") of a gas containing a doping element, preferably a gas containing nitrogen, boron, phopshore and / or fluorine, or the injection of hydrogen, together with the carbon gas, by the same orifice (9 \ 9 ", 9 '") as the carbon gas or through a separate orifice (8).

13. Use of carbonaceous agglomerates containing metastable carby chains / carbynoids obtained by the method according to any one of claims 1 to 7 for the synthesis of chemical molecules containing polyenic chains, and / or polycyclic, and / or for the formation of compliant coverings only in carbon compounds, and / or for the synthesis of graphenes, graphites, nano-diamonds, fullerenes.

 14. Use of the carbonaceous agglomerates containing metastable carbyne / carbynoid chains obtained by the process according to any one of claims 1 to 7 as a semiconductor material.

 15. Use of the carbonaceous agglomerates containing metastable carby chains / carbynoids obtained by the method according to any one of claims 1 to 7 for the manufacture of components of electronic devices.

 16. Use of carbonaceous agglomerates containing metastable carby chains / carbynoids obtained by the method according to any one of claims 1 to 7 for energy storage.