EP1771597A2

EP1771597A2 - Synthesis of a self assembled hybrid of ultrananocrystalline diamond and carbon nanotubes

Info

Publication number: EP1771597A2
Application number: EP05857452A
Authority: EP
Inventors: Xiao Xingcheng; John A. Carlisle; Orlando Auciello; Jeffrey W. Elam; Dieter M. Gruen
Original assignee: University of Chicago
Current assignee: University of Chicago
Priority date: 2004-06-10
Filing date: 2005-06-10
Publication date: 2007-04-11
Also published as: KR20070072849A; WO2006085925A3; WO2006085925A2

Abstract

A material of carbon nanotubes and diamond bonded together. A method of producing carbon nanotubes and diamond covalently bonded together is disclosed with a substrate on which is deposited nanopart: iLcles of a suitable catalyst on a surface of the substrate. A diamond seeding material is deposited on the surface of the substrate, and then the substrate is exposed to a hydrogen poor plasma for a time sufficient to grow carbon nanotubes and diamond covalently bonded together.

Description

SYNTHESIS OF A SELF ASSEMBLED HYBRID OF ULTRANANOCRYSTALLINE DIAMOND AND CARBON

NANOTUBES

CONTRACTUAL ORIGIN OF THE INVENTION

The United States Government has rights in this invention pursuant to

Contract No. W-31-109-ENG-38 between the U.S. Department of Energy (DOE) and

The University of Chicago representing Argonne National Laboratory.

FIELD OF THE INVENTION

The present invention relates to various combinations of carbonaceous

materials, particularly those with interesting electrical and hardness properties.

BACKGROUND OF THE INVENTION

Recent strong scientific and technological interest in nanostructured carbon

materials (nanocarbons) has been motivated by the diverse range of physical properties

these systems exhibit. These properties arise from the many different local bonding

structures of carbon, as well as the long range order of the bonding structure. For

example, carbon nanotubes (CNTs) are distinct from graphite although both consist

essentially of sp²-bonded carbon. CNT's are the strongest known material and also

exhibit unique electronic transport properties, making them candidates for a wide range

of applications.

Similarly, nanocrystalline diamond films are distinct from single crystal diamond

although both are mostly sp³-bonded carbon, and exhibit high hardness, exceptional

chemical inertness, biocompatibility and negative electron affinity with properly

treatment. The unique mechanical and electrochemical properties of nanocrystalline diamond make it a promising candidate as the protective coating for machining tools,

hermetic corrosion resistant coating for biodevices, cold cathode electron source, and

the structural material for micro- and nano- electromechanical systems (MEMS/ NEMS).

It is believed that a combination of carbon nanotubes and nanocrystalline

diamond provides materials with novel properties that are advantageously used in

applications such as electronic devices or MEMS/ NEMS. However, until now no

method of providing the concurrent growth of different allotropes of carbon that are

covalently bonded and organized at the nanoscale has been available.

SUMMARY OF THE INVENTION

Accordingly, an object of the invention is to provide a synthesis of

nanocrystalline diamond and carbon nanotubes to form a covalently bonded hybrid

material: a nanocomposite of diamond and CNTs

Another object of the invention is to provide a material comprising carbon

nanotubes and diamond covalently bonded together.

Another object of the invention is to provide a method of producing carbon

nanotubes and diamond covalently bonded together, comprising providing a substrate,

depositing nanoparticles of a suitable catalyst on a surface of the substrate, depositing

diamond seeding material on the surface of the substrate, and exposing the substrate

to a hydrogen poor plasma for a time sufficient to grow carbon nanotubes and diamond

covalently bonded together.

Another object of the invention is to provide a hybrid of carbon nanotubes and

diamond made by the method of providing a substrate, depositing nanoparticles of a

suitable catalyst on a surface of the substrate, depositing diamond seeding material on the surface of the substrate, and exposing the substrate to a hydrogen poor plasma for

a time sufficient to grow a hybrid of carbon nanotubes and diamond.

The invention consists of certain novel features and a combination of parts

hereinafter fully described, illustrated in the accompanying drawings, and particularly

pointed out in the appended claims, it being understood that various changes in the

details may be made without departing from the spirit, or sacrificing any of the

advantages of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of facilitating an understanding of the invention, there is

illustrated in the accompanying drawings a preferred embodiment thereof, from an

inspection of which, when considered in connection with the following description, the

invention, its construction and operation, and many of its advantages should be readily

understood and appreciated.

FIGURE Ia is a SEM showing the evolution of the hybrid UNCD/ CNTs

structures via adjustment of the relative fraction of catalyst and nanodiamond seeds;

FIG. Ib is a SEM showing the hybrid structures of UNCD and CNTs with a

low fraction of CNTs and UNCD;

FIG. Ic is a SEM having a fully dense hybrid structure of UNCD and CNTs

with a high fraction of UNCD;

FIG. Id is a SEM showing pure UNCD;

FIG. 2a is a TEM image of CNTs prepared using PECVD with Ar/ CH₄ as

precursor with different diameters of CNTs ranging from 2 to 10 ran;

FIG. 2b is a HRTEM image of CNTs multiwalled with well-ordered graphene sheets and typical defect densities;

FIG. 3 is a graphical representation of a Raman spectra of CNTs, UNCD and

UNCD/CNTs hybrid structures corresponding to the samples shown in Figs. Ia, b-

d, respectively;

FIG. 4 is a graph of C Is NEXAFS of CNTs, UNCD and UNCD/CNTs hybrid

structures, corresponding to the samples shown in Figs, la-d, respectively,

nanodiamond seeds; and

FIGS. 5-14 are SEM images of covalently bonded diamond and CNTs of the

hybrid materials; and

FIG. 15 is a schematic representation of a combination of carbon nanotubes

and diamond nanoparticles, each in predetermined patterns.

DETAILED DESCRIPTION OF THE INVENTION

One of the most commonly used processes for preparing nanostructured carbon

materials is plasma enhanced chemical vapor deposition (PECVD), in which chemically

activated carbon-based molecules are produced; however, this invention includes any

known method of depositing nonstructural carbon materials. For instance, different

carbon-rich combinations of C₂H₂/ H₂, C₂H₂/ NH₃, and CH₄/ Ar have been employed for

growing CNTs. In contrast, hydrogen-rich (~99% H₂) CH₄/ H₂ plasmas are the most

common mixtures used for growing microcrystalline diamond films, wherein large

amounts of atomic hydrogen play a critical role in both the gas-phase and surface

growth chemistries. Importantly, atomic hydrogen is also needed to selectively etch the

non-diamond carbon during growth. Over the past several years Argonne National

Laboratory (ANL) has developed hydrogen-poor Ar/ CH₄ (99% Ar, 1 % CH₄) chemistries to grow ultrananocrystalline diamond (UNCD) films, which consist of diamond grains

3-5 nm in size and atomically abrupt high energy grain boundaries, as described by A.

Krauss, O. Auciello, D. Gruen, A. Jayatissa, A. Sumant, J. Tucek, D. Mancini, N.

Moldovan, A. Erdemir, D. Ersoy, M. Gardos, H. Busmann, E. Meyer, M. Ding, Diamond

Relat. Mater. 2001, 10, 1952, incorporated herein by reference.

The special nanostructure of UNCD yields a unique combination of properties,

such as low deposition temperatures, described by X. Xiao, J. Birrell, J. E. Gerbi, O.

Auciello, J. A. Carlisle, J. Appl. Phys. 2004, 96, 2232, incorporated herein by reference,

excellent conformal growth on high-aspect ratio features, described by A. Krauss, O.

Auciello, D. Gruen, A. Jayatissa, A. Sumant, J. Tucek, D. Mancini, N. Moldovan, A.

Erdemir, D. Ersoy, M. Gardos, H. Busmann, E. Meyer, M. Ding, Diamond Relat. Mater.

2001, 10, 1952, incorporated herein by reference and the highest room-temperature

n-type electronic conductivity demonstrated for phase-pure diamond films via nitrogen

doping at the grain boundaries, as described by S. Battacharyya, O. Auciello, J. Birrell,

J. A. Carlisle, L. A. Curtiss, A. N. Goyete, D.M. Gruen, A. R. Krauss, J. Schlueter, A.

Sumant, P. Zapol, Appl. Phys. Lett. 2001, 79,1441. incorporated herein by reference.

It is important to recognize that the composition and morphology of the material

grown is not simply a function of the gas mixture and plasma conditions, but also

depends sensitively on the pretreatment of the substrate prior to growth as well as the

substrate temperature. It is widely known that there is a high nucleation barrier for

growing carbon based materials and that certain pre-treatments are necessary to

provide the initial nucleation sites. For example, nanoparticles of transition metals, such

as Ni, Fe and Co are used as catalysts for growing CNTs, whereas micro or nano-diamond UNCD powders are typically needed to be present on the substrate

surface prior to the diamond growth. In addition, the temperature window for PECVD

growth of CNTs ranges from 150⁰C while UNCD films can be prepared at temperature

ranged from 400⁰C to 800⁰C.

Experimental

Iron films with different thickness (~5 ~ 40 ran) were deposited on silicon

substrates using an ion beam sputtering deposition system with a Kr ion gun. The

coated samples were then immersed into a suspension of ~5 nm diamond particles in

methanol and ultrasonically vibrated for different periods of time in order to control the

nucleation density for the growth of UNCD. Next, the seeded films were inserted into

a microwave plasma deposition system (IPLAS) and heated at 800 ⁰C in flowing

hydrogen (90 seem, 20 mbar) for 30 minutes to coalesce the iron films into nano-sized

iron particles to catalyze CNTs formation. The iron film thickness determines the size

of the catalyst particles, which subsequently determines the diameter of CNTs.

Following the pretreatment described above, the substrate was cooled down to 700⁰C

and a plasma consisting of 99% Ar with 1% CH₄ was initiated to grow the carbon

nanocomposite .

A number of specific experiments used the following protocol:

Experimental details:

1. Clean the substrate (Silicon, Silcion oxide, W and other carbide formed

metal) using acetone and methanol for 5 minutes separately.

2. Sputter the transition metals (Fe, Ni, Co) to the cleaned substrate with

different thickness (0, 5, 10, 20 and 40nm). 3. Ultrasonically seed the substrate in nanodiamond suspension (3mg nano

diamond powder in 100ml methanol) with different time (0, 5, 15, 30 minutes), then

rinse with methanol.

4. Heat the sample up to 800⁰C and input H₂ flow (90 seem, 20 mbar) for 20

minutes to reduce the possibly oxidized metal and break the continuous film into nano

particles. The size and density of nano particles are dependent of thickness of metal

films and in turn influence the diameters and density of carbon nanotubes accordingly.

5. Decrease the substrate temperature down to 600-700⁰C and switch off the

hydrogen flow, wait for 5 minute pumping down.

6. Expose the treated substrate to hydrogen poor Ar/CH₄ plasma (49 seem

Ar and 1 seem CH₄ the typical flow rate for growing ultrananocrystalline diamond) for

different time (10, 20, 30 minutes).

We determined the following from the experimental data:

1. The relative fraction of ultrananocrystalline diamond and carbon

nanotubes is controlled by the combination of seeding time, thickness of catalyst thin

films and growth time.

2. Thickness of the catalyst thin films not only control the catalyst particle

size but also control the catalyst density, which in turn control the diameter and density

of catalyst.

• Pure ultrananocrystalline diamond is obtained without catalyst

deposition on substrate, as shown in Fig. Ia;

• Nerve structures are obtained with process of 5 minute seeding, 10

ran catalyst and 10 minute growth; as shown in Fig. Ib; a

• Structure with the protrusion of carbon nanotubes through

supergrain boundaries are obtained with the process parameters

of 30 minute seeding, 10 nm catalyst, 30 minute growth, as shown

in Fig. Ic;

• Pure UNCD are obtained without transition metal sputtering as

shown in Fig. Id;

3. Setting the process parameters in the overlapped process windows

resulted in carbon nanotubes and ultrananocrystalline diamond.

4. Patterned templates for seeds and catalyst were utilized to simultaneously

and selectively grow carbon nanotubes and ultrananocrystalline diamond to fabricate

the prototype of electronic devices.

5. Uniform distribution of carbon nanotubes in diamond matrix enhances

the fracture roughness of diamond thin films and overcomes the shortcomings of

brittleness.

The hybrid nanostructures were studied using a Hitachi S-4700 field emission

Scanning Electron Microscope (SEM) at 10 kV accelerating voltage and a TECNAI 20

Transmission Electron Microscope (TEM) with Electron Energy Loss Spectroscopy

(EELS) at 10OkV accelerating voltage. The hybrid films were also analyzed with visible

Raman spectroscopy using a Renishaw Raman microscope in the backscattering

geometry with a HeNe laser at 633 nm and an output power of 25 mW focused to a spot

size of ~ 2 μm. Near Edge X-ray Absorption Fine Structure (NEXAFS) analysis was

performed at the Advanced Light Source of Lawrence Berkeley National Laboratory.

The diamond reference sample was a standard Type Ha diamond. The graphite reference sample was a highly oriented pyrolitic graphite (HOPG).

By selectively placing the catalyst and nanodiamond powders on the same

substrate, carbon nanotubes and UNCD can be grown. The relative fraction of UNCD

and CNTs can be varied by controlling the relative amounts of transitional metal

catalysts and nanodiamond seeds. The first successful preparation of the hybrid

CNT/ UNCD nanostructures using this approach is set forth hereafter.

Fig. 1 shows SEM images revealing the structural evolution from pure CNTs to

pure UNCD films as the relative fraction of Fe and diamond nanoparticles was varied.

Pure CNTs (Fig. Ia) were observed when only Fe catalyst particles were present on the

substrate, whereas "normal" UNCD resulted when only nanodiamond particles were

present (Fig.1 d) . Seeding with both types of catalyst particles leads to the simultaneous

growth of both UNCD and CNT in all cases, but controlling the relative amounts of

these two allotropes further requires careful control of temperature and deposition time,

since CNTs normally grow much faster than UNCD. This is shown in the SEM data

presented in Fig. Ib and Ic. For sufficiently short deposition times (~30 min.), the

formation of isolated "supergrains" consisting of many nanosized crystalline diamond

grains on the substrate is observed. Since the catalyst and nanodiamond powder were

present at the same time in the plasma, UNCD and CNTs were simultaneously grown

on those seeds and catalyst. The supergrains shown in Fig. Ib appear, in fact to be

interconnected by CNTs, with both ends of some individual nanotubes terminating on

different supergrains. It is possible that the plasma environment causes local charging

effects that lead to attractive forces to arise between the UNCD supergrains and CNTs,

but it is also possible that UNCD and CNT can grow into each other. It may be that the CNTs and UNCD are covalently bonded together or it may be

that the combination is a hybrid, but whichever form it may be, the composition is new.

To realize useful materials such as for MEMS and wear-resistant coatings, it will be

necessary to produce fully-dense that is substantially free of voids, covalently-bonded

(or hybrid) structures. Fig. Ic shows a SEM image of a material that very nearly realizes

this goal. Further increase of the diamond nucleation density relative to the Fe catalyst

enhanced the growth of UNCD relative to CNTs, and the CNTs are clearly present at

the boundaries between the supergrains (Fig. Ic). Energy-dispersive x-ray (EDX) data

(not shown) revealed the presence of Fe at the tips of the structures between the

supergrains.

The carbon nanotubes shown in Fig. Ia were further investigated by TEM (Fig.

2), which showed a typical bundled multiwall (MWCNT) morphology. The catalytic

particles were also observed, as shown in the top left area of Fig. 2a. HRTEM images

revealed that the nanotubes had diameters in the range of about 2 to 10 nm and the

nanotube walls were comprised of reasonably well-ordered graphene sheets. The

carbon nanotubes are defective, as is typical for CNTs prepared by PECVD under these

conditions. Furthermore, the HRTEM and EELS results on the sample shown in Fig. Ib

confirmed the coexistence of CNTs and UNCD (not shown here).

Fig. 3 compares the Raman spectra of UNCD, CNT, and the UNCD/CNT

nanocomposite in the range 100~300 cm-1. Radial breathing mode (RBM) peaks are

clearly observed in the Raman spectra of CNTs and the nanocomposite, which indicates

the presence of small diameter single- or double-wall CNTs, in addition to the

somewhat larger diamond MWCNT that were observed via TEM. Interestingly, the peak positions in the pure CNT sample compared to the hybrid UNCD/ CNTs materials

are consistently different, which may be indicative of slightly different growth regimes

for the two materials (e.g. the presence of only Fe particles versus Fe+ nanodiamond

particles). The estimated inner-diameters are on the order of one nm, which may

correspond to the some of the smaller CNTs shown in HRTEM pictures. No RBM is

detected in pure UNCD, even for the graphitic phase along the grain boundaries.

Further research is undergoing in our lab to explore the relationships between the RBM

peaks and process parameters.

Near-edge x-ray absorption fine structure (NEXAFS) is a useful tool to

unambiguously distinguish the Sp² bonding and sp³ bonding in carbon materials. C (Is)

NEXAFS data obtained from pure CNTs, pure UNCD, and the UNCD/ CNT shown in

Fig. Ic are shown in Fig.4. UNCD films consist of about 95% sp³-bonded carbon, with

5% sp² bonded carbon within the grain boundaries which occupy 10% of the UNCD

volume. Thus the C Is NEXAFS from UNCD looks similar to data obtained from

high-quality microcrystalline diamond or single crystal diamond except for the presence

of an sp² π* peak at 285.5 eV. In contrast, the spectrum obtained from the pure CNTs

sample looks very similar to those obtained from a typical graphite reference (highly

oriented pyrolytic graphite), with both the π* at 285.5 eV and the sp² σ* core exciton at

~291.5 eV clearly visible. This is consistent with the observation of good local order in

the CNTs shown in Figure 2.

The NEXAFS spectrum of a CNT/ UNCD hybrid structure shows the combined

signals from both CNTs and diamond. The peak intensity around 285 eV in the

nanocomposite is higher and the dip around 302 eV is shallower than the corresponding ones in UNCD, implying a slightly higher fraction of the graphite phase resulting from

CNTs and the grain boundaries of UNCD. These data provide direct evidence that the

growth of UNCD (and probably CNTs) proceed independently in the hybrid as they do

during the growth of the composite.

It is the overlap of the process parameters for growing UNCD and CNTs, in

particular the reduced amount of atomic hydrogen, that makes it possible to

simultaneously grow the UNCD/ CNT hybrid. CNTs grow readily in Ar-rich Ar/CH₄

discharges due to the abundance of C₂H₂ in these plasmas via the thermal

decomposition of CH₄ at 1600K plasma temperatures. It is believed that C₂H₂

decomposed on the Fe nanoparticles, leading to the formation and diffusion of carbon

atoms in the catalyst and the growth process for CNTs. However, several other carbon

species have also been considered as growth species for CNTs, including CH₃ which is

widely regarded as the principal growth species for most PECVD deposited diamond

thin films. Our data indicate that the relative proportion of the two species is governed

by kinetics and not the competing energetics of CNTs and UNCD growth. In previous

work it was demonstrated that the same hydrogen-poor plasmas can still selectively

etch the side walls of the horizontally oriented MWCNTs under an Ar-rich Ar/ CH₄

discharge, leading to the growth of graphitic structures on the sidewalls, as described

by S. Trasobares, C. P. Ewels J. Birrell, O. Stephen, B. Q. Wei, J. A. Carlisle, D. Miller, P.

Keblinski, P. M. Ajayan, Adv. Mat. 2004, 16, 610, incorporated herein by reference.

Since the process parameters for growing both nanocarbon materials are the

same in Ar/ CH₄ plasma, the key factor determining the subsequent nonstructural

development is the initial nucleation sites. Fabricating periodic arrays of UNCD and CNTs by patterning nanodiamond and catalyst particles with the aid of lithographic

techniques such as electron-beam lithography, n-type conductive various geometries

such as films of heterojunctions between conductive UNCD and CNTs are capable of

being produced, such as but not limited to semiconductors, MEMS devices and the like

and Figures 5-15 are SEM images of the hybrid materials produced by the methods

disclosed herein.

To summarize, a new synthesis pathway has been developed to combine

different allotropes of carbon at the nanoscale in covalently bonded structures. The

synthesis of a hybrid nanocarbon material consisting of ultrananocrystalline diamond

and carbon nanotubes has been successfully demonstrated for the first time, via the

exposure of a surface consisting of nano-sized diamond powders and iron nanoparticles

to a hydrogen-poor carbon-containing plasma. This method offers a novel approach to

modulate the relative ratio of sp²- and sp³-bonded carbon to form self-assembled carbon

nanostructures that is amendable to modern patterning techniques to further organize

these structures for useful purposes. Potential applications of these new hybrid

structures ranging from nano-electronics to bio-MEMS.

In the manufacture of a variety of devices, such as semiconductors, a substrate

such as but not limited to W, Ta, Ti, Mo, Cu, Si, SiO₂, mixtures and alloys thereof may

be used. The diamond may be nanocrystalline or UNCD and may be electrically

conducting or not. Nitrogen doping of UNCD provides an n-type electrical conductor.

The growth plasma used to grow the composite materials can be further tailored

to change the electrical transport properties of the UNCD. In addition to the "normal"

plasmas used to grow undoped UNCD (about 99% Ar and 1% CH4), plasmas with either extra nitrogen (N2) or boron (either diborane or trimethylboron) added to the gas

mixture leads to the growth of n- type or p-type UNCD, respectively. Co-integration of

highly room-temperature conductive n-type UNCD with CNTs will further increase the

electrical conductivity of the hybrid material and also improve its use in cold-cathode

electron sources or as electrodes in supercapacitors. P-type UNCD, when integrated

with carbon nanotubes which are normally n-type conductive, will give rise to

interesting photonic properties suitable to the conversion of solar energy into electrical

energy.

The use of patterning techniques (such as photolithography, e-beam lithography,

and others approaches) are used to control the location of the nanotubes and UNCD

relative to each other. As seen in Fig. 15, a nanotube catalyst can be patterned on a

substrate as an arrays of dots on a substrate surface with arbitrary diameter and pitch

(1), after which diamond nanoparticles (which lead to the growth of UNCD) are

ultrasonicated onto the patterned surface (2), and the growth then leads to the UNCD

and CNTS having distinct locations within the hybrid material. The pattern and

location of the diamond nanoparticles themselves are controlled (instead of or in

addition to) the CNT catalyst particles to grain further control over the growth and

microstructure.

The alignment of the carbon nanotubes within the hybrid thin film materials can

be controlled via the application of electric fields (commonly accomplished by applying

a bias voltage during growth). Vertically aligned carbon nanotubes have been grown

by many groups using microwave plasma chemical vapor deposition. Such an

integration of vertically aligned carbon nanotubes within a UNCD matrix will have anisotropic transport and mechanical properties. For instance, the electrical

conductivity of the hybrid thin film as a whole is higher in the direction parallel with

the alignment of the CNTs and much lower perpendicular to the alignment. Mechanical

properties such as the fracture toughness & strength, hardness, and Young's modulus

will also exhibit similar behavior.

The use of more exotic catalyst materials (such as CoMo alloys) produces

predominantly single wall (instead of multiwalled) carbon nanotubes and the growth

of single-walled nanotubes that are semiconducting versus metallic. Integration of

single walled material (which is distinct from multiwalled and exhibit ballistic (zero

resistance) electron transport, ultra-high thermal conductivities, and the highest

material strength of any known material is a very valuable aspect of the invention.

While the invention has been particularly shown and described with reference

to a preferred embodiment hereof, it will be understood by those skilled in the art that

several changes in form and detail may be made without departing from the spirit and

scope of the invention.

Claims

The embodiments of the invention in which an exclusive property or privilegeis claimed are defined as follows:

1. A material comprising a film substantially free of voids containing a

hybrid of carbon nanotubes and diamond.

2. The material of claim 1, wherein said diamond is substantially all

nanocrystalline diamond.

3. The material of claim 1, wherein said diamond is substantially all

ultrananocrystalline (UNCD) diamond.

4. The material of claim 1, wherein said diamond is nitrogen doped and is

electrically conducting.

5. The material of claim 1, wherein said diamond and said carbon nanotubes

are covalently bonded.

6. The material of claim 1, wherein said carbon nanotubes have average

diameters in the range of from about 2 to about 10 nanometers.

7. The material of claim 1, wherein said carbon nanotubes include both

single and multiple walled tubes.

8. The material of claim 1, in the form of a thin film having a thickness not

less than about 3 nanometers (nms).

9. A method of producing a film containing a hybrid of carbon nanotubes

and diamond comprising

providing a substrate,

depositing nanoparticles of a suitable catalyst on a surface of the substrate,

depositing diamond seeding material on the surface of the substrate, and

exposing the substrate to a hydrogen poor plasma for a time sufficient to grow a film

containing carbon nanotubes and diamond.

10. The method of claim 9, wherein the substrate is Si and/ or SiO₂ and/ or a

refractory metal of Cu or mixtures or alloys thereof and the catalyst is one or more of Fe,

Ni and Co.

11. The method of claim 9, wherein the hydrogen poor plasma is a

combination of CH₄ and Ar.

12. The method of claim 9, wherein the carbon nanotubes and diamond are

produced by plasma-enhanced chemical vapor deposition and are covalently bonded.

13. The method of claim 12, wherein the plasma is microwave induced and is

substantially a mixture of 1% CH₄ and 99% Ar.

14. The method of claim 13, wherein the diamond is substantially UNCD and

the covalently bonded carbon nanotubes and UNCD are in the form of a thin film

substantially free of voids and having a thickness not less than about 3 nms.

15. The method of claim 14, wherein the UNCD has grain boundaries and is

doped with nitrogen or boron thereat and is electrically conducting and the substrate is

Si and/ or SiO₂.

16. The method of claim 15, wherein the ratio of diamond to carbon nanotubes

is controlled by the amount of the transition metal nanoparticles and diamond seeding

material deposited on the substrate and the time the substrate is exposed to the plasma.

17. The method of claim 9, wherein the average diameters of the carbon

nanotubes are controlled by the diameter of the transition nanoparticles on the substrate.

18. The method of claim 9, wherein the diameters of the transition

nanoparticles are controlled by the thickness of the film formed by sputtering

nanoparticles of a transition metal on the substrate.

19. The method of claim 9, wherein transition nanoparticles are produced by

heating transition metal thin films at about 800EC in flowing hydrogen.

20. A hybrid of carbon nanotubes and diamond made by the method,

comprising providing a substrate,

depositing nanoparticles of a suitable catalyst on a surface of the substrate,

depositing diamond seeding material on the surface of the substrate, and

exposing the substrate to a hydrogen poor plasma for a time sufficient to

grow a hybrid of carbon nanotubes and diamond.

21. The hybrid of claim 20, wherein said substrate is Si and/ or SiO₂, said

transition metal is one or more of Fe, Ni and Co, and mixtures of alloys thereof, said

diamond seeding material is nanocrystalline diamond powder, and said plasma includes

at least about 99% Ar.

22. The hybrid of claim 20, in the form of a thin film having a thickness of

about 3 nms to about 3 micrometers and is substantially free of voids.

23. The hybrid of claim 22, wherein said diamond is UNCD and is nitrogen

doped and is electrically conducting.

24. A material substantially without voids and as shown in Figs. 5-14.

25. A material substantially free of voids containing a hybrid of carbon

nanotubes and diamond in which the carbon nanotubes form a first predetermined

pattern.

26. The material of claim 25, wherein said diamond is substantially all

ultrananocrystalline (UNCD) diamond.

27. The material of claim 26, wherein said diamond is doped with nitrogen or

boron and is electrically conducting.

28. The material of claim 25, wherein said carbon nanotubes are predominately

single-walled tubes.

29. The material of claim 25, wherein said carbon nanotubes are substantially

vertically aligned.

30. The material of claim 25, wherein said UNCD is in a second predetermined

pattern and said carbon nanotubes are predominately single-walled and substantially

vertically aligned.

31. A method of producing carbon nanotubes and diamond comprising

providing a substrate in a first predetermined pattern,

depositing nanoparticles of a suitable catalyst on a surface of the substrate

in a second predetermined pattern,

depositing diamond seeding material on the surface of the substrate, and

exposing the substrate to a hydrogen poor plasma for a time sufficient to grow carbon nanotubes in a first predetermined pattern and diamond in a second predetermined

pattern.

32. The method of claim 31, wherein the substrate is Si and/ or SiO₂ and/ or a

Ni and Co or alloys thereof.

33. The method of claim 31, wherein the hydrogen poor plasma is a

combination of CH₄ and Ar and one or more of nitrogen or a born containing vapor in

dopant quantities.

34. The method of claim 32, wherein the carbon nanotubes are substantially

vertically aligned by applying an electrical bias during the formation thereof.

35. An article including the carbon nanotubes and diamond made by the

method of claim 31.