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1.
G. Lehmann P. Hess S. Weissmantel G. Reisse P. Scheible A. Lunk 《Applied Physics A: Materials Science & Processing》2002,74(1):41-45
Cubic boron nitride (c-BN) films of 200–420 nm thickness and high phase purity were deposited on silicon (100) substrates
by ion-assisted pulsed laser deposition (IA PLD)from a boron nitride target using a KrF-excimer laser, and by plasma-enhanced
physical vapor deposition (PE PVD)with a hollow-cathode arc evaporation device. In order to improve the c-BNfilm adhesion,
hexagonal boron nitride (h-BN) films with 25–50 nm thickness were used as buffer layers. The density and Young’s modulus of
the c-BNfilms were obtained by investigating the dispersion of surface acoustic waves. In data analysis a two-layer model
was applied in order to take the influence of the h-BNlayer into consideration. The values for the density vary from 2.95±0.25 g/cm3to 3.35±0.3 g/cm3, and those for the Young’s modulus from 420±40 GPa to 505±30 GPa. The results are compared with literature values reported
for nanocrystalline films, polycrystalline disks and single crystal c-BN.
Received: 26 March 2001 / Accepted: 29 March 2001 / Published online: 25 July 2001 相似文献
2.
L.-W. Yin M.-S. Li J.-J. Cui Y.-J. Song F.-Z. Li Z.-Y. Hao 《Applied Physics A: Materials Science & Processing》2001,73(5):653-657
For understanding the mechanism of diamond growth at high temperature–high pressure (HTHP) from a metallic catalyst–graphite
system, it is of great interest to perform atomic force microscopy (AFM) experiments, which provide a unique technique different
from that of normal optical and electronic microscopy studies, to study the topography of HTHP as-grown diamond single crystals.
In the present paper, we report first AFM results on diamond single crystals grown from a Fe-Ni-C system at HTHP to reveal
the growth mechanism of diamond single crystals at HTHP. AFM images for as-grown diamond samples show dark etch pits on the
(111) surface, indicating dislocations. Some fine particles about 100–300 nm in dimension were directly observed on the (100)
diamond surface. These particles are believed to have been formed through transition of graphite to diamond under the effect
of the catalyst and to have been transported to the growing diamond surface through a metallic thin film by diffusion. The
roughness of the (100) diamond surface is found to be about several tens of nanometers through profile analysis. The diamond
growth at HTHP, in a sense, could be considered as a process of unification of these fine diamond particles or of carbon-atom-cluster
recombination on the growing diamond crystal surface. Successive growth interlayer steps on the (111) diamond surface were
systemically examined. The heights of the growth interlayer steps were measured by sectional analysis. It was shown that the
heights of the growth interlayer steps are quite different and range from about 10 to 25 nm. The source of the interlayer
steps might be dislocations. The diamond-growth mechanism at HTHP could be indicated by the AFM topography of the fine diamond
particles and the train-growth interlayer steps on the as-grown diamond surfaces.
Received: 29 March 2001 / Accepted: 20 August 2001 / Published online: 2 October 2001 相似文献
3.
L.-W. Yin M.-S. Li Z.-Y. Hao Y.-J. Bai Z.-G. Gong F.-Z. Li 《Applied Physics A: Materials Science & Processing》2001,73(5):535-538
M?ssbauer spectroscopy has been used to systemically study the catalytic mechanism of Fe-based alloys in diamond formation
at high temperature–high pressure (HTHP) for the first time. M?ssbauer spectra reveal the magnetic state of the 3d electrons
of a Fe atom in the Fe-based alloy catalyst during diamond formation at HTHP. During carburization at lower temperatures than
that required for diamond formation and diamond formation in the diamond-stability region using Fe-based alloys as a catalyst,
both the quadrupole splitting QS and the isomer shift IS change from negative to positive, especially reaching a state in
which they are zero. It was indicated that the state of the 3d-shell electrons of the iron atom changes greatly during carburization
and diamond formation and that the incomplete 3d sub-bands of Fe atoms in the catalyst alloys could be filled up in proper
order by electrons of interstitial carbon atoms. During diamond formation, the unpaired 3d-shell electrons of an iron atom
in the Fe-based alloy absorb and interact with 2Pz electrons of the carbon atoms. There exist a Fe–C bonding and an electron charge transfer stage. The 2Pz electrons of the carbon atoms could be dragged into the metal atoms in the catalyst alloy and would make a transition of
triangular (sp2π) hybridization of valence electrons to tetrahedral (sp3) hybridization of valence electrons (a transition of sp2π bonds of graphite to sp3 bonds of diamond), resulting in a transition of graphite structure to diamond. Although the conclusion of this study is strictly
applicable only to Fe-based alloy catalysts, it could be considered more general because of the chemical similarities between
the transition elements used as solvent catalysts for diamond synthesis.
Received: 2 March 2001 / Accepted: 20 August 2001 / Published online: 2 October 2001 相似文献
4.
Femtosecond ablation of ultrahard materials 总被引:4,自引:0,他引:4
G. Dumitru V. Romano H.P. Weber M. Sentis W. Marine 《Applied Physics A: Materials Science & Processing》2002,74(6):729-739
Several ultrahard materials and coatings of definite interest for tribological applications were tested with respect to their
response when irradiated with fs laser pulses. Results on cemented tungsten carbide and on titanium carbonitride are reported
for the first time and compared with outcomes of investigations on diamond and titanium nitride. The experiments were carried
out in air, in a regime of 5–8 J/cm2 fluences, using the beam of a commercial Ti:sapphire laser. The changes induced in the surface morphology were analysed with
a Nomarski optical microscope, and with SEM and AFM techniques. From the experimental data and from the calculated incident
energy density distributions, the damage and ablation threshold values were determined. As expected, the diamond showed the
highest threshold, while the cemented tungsten carbide exhibited typical values for metallic surfaces. The ablation rates
determined (under the above-mentioned experimental conditions) were in the range 0.1–0.2 μm per pulse for all the materials
investigated.
Received: 31 August 2001 / Accepted: 3 December 2001 / Published online: 20 March 2002 相似文献
5.
L.W. Yin M.S. Li Z.D. Zou D.S. Sun Z.Y. Hao Z.G. Gong Z.Y. Yao 《Applied Physics A: Materials Science & Processing》2001,72(3):373-375
The growth-front interface of a diamond single crystal, which was grown from the Fe-Ni-C system under high pressure and high
temperature (HPHT), has been directly observed by transmission electron microscopy (TEM) for the first time. The presence
of a cellular interface suggests that the diamond is grown from solution and there exists a narrow supercooling zone in front
of the solid–liquid interface. Diamond-growth parallel layers were also found, which indicates that the diamond grows from
solution layer by layer. It provides direct evidence that the diamond is synthesized through graphite dissolution and transformation
to subcritical diamond particles in a molten catalyst, diamond subcritical particle connection to form diamond clusters, diffusion
of the diamond clusters to the growing diamond, and unification of the diamond clusters on the growing diamond crystal.
Received: 17 July 2000 / Accepted: 27 October 2000 / Published online: 10 January 2001 相似文献
6.
A relation between a metallic film covering on diamond formed during growth and nanosized inclusions in HPHT as-grown diamond single crystals 总被引:3,自引:0,他引:3
L.-W. Yin M.-S. Li Z.-G. Gong Y.-J. Bai F.-Z. Li Z.-Y. Hao 《Applied Physics A: Materials Science & Processing》2003,76(7):1061-1065
One of the most important characteristics and basic phenomena during diamond growth from liquid metal catalyst solutions saturated
with carbon at high temperature–high pressure (HPHT) is that there exists a thin metallic film covering on the growing diamond,
through which carbon-atom clusters are delivered to the surface of the growing diamond by diffusion. A study of microstructures
of such a metallic film and a relation between the thin metallic film and the inclusions trapped in HPHT as-grown diamond
single crystals may be helpful to obtain high-purity diamond single crystals. It was found that both the metallic film and
the HPHT as-grown diamond single crystals contain some nanostructured regions. Examination by transmission electron microscopy
suggests that the microstructure of the thin metallic film is in accordance with nanosized particles contained in HPHT as-grown
diamond single crystals. The nanosized particles with several to several tens of nanometers in dimension distribute homogeneously
in the metallic film and in the diamond matrix. Generally, the size of the particles in the thin metallic film is relatively
larger than that within the diamond matrix. Selected area electron diffraction patterns suggest that the nanosized particles
in the metallic film and nanometer inclusions within the diamond are mainly composed of f.c.c. (FeNi)23C6, hexagonal graphite and cubic γ-(FeNi). The formation of the nanosized inclusions within the diamond single crystals is thought
not only to relate to the growth process and rapid quenching from high temperature after diamond synthesis, but also to be
associated with large amounts of defects in the diamond, because the free energy in these defect areas is very high. The critical
size of carbide, γ-(FeNi)and graphite particles within the diamond matrix should decrease and not increase according to thermodynamic
theory during quenching from HPHT to room temperature and ambient pressure.
Received: 13 September 2001 / Accepted: 12 June 2002 / Published online: 17 December 2002
RID="*"
ID="*"Corresponding author. Fax: +86-0531/295-5081; E-mail: yinlw@sdu.edu.cn 相似文献
7.
X.W. Zhang H.-G. Boyen P. Ziemann F. Banhart 《Applied Physics A: Materials Science & Processing》2005,80(4):735-738
Heteroepitaxial cubic boron nitride (c-BN) films of significantly improved crystalline quality have successfully been deposited on (001) diamond single crystals using an ion beam assisted preparation method. The results of various characterization techniques prove that films containing 100% pure c-BN phase were nucleated directly on top of diamond without any intermediate hexagonal BN layer. Epitaxially grown, 500-nm-thick c-BN films are mechanically stable even under ambient conditions, though they still exhibit a compressive stress of 5 GPa. Their rocking angles of 0.2°, as observed by X-ray diffraction, point to a hitherto unprecedented quality of the films. Their surface smoothness, the magnitude of their Youngs modulus as well as their ultrahardness corroborate the outstanding quality of these epitaxially grown c-BN films on single-crystalline diamond. PACS 68.55.Jk; 81.15.Jj; 62.20.Qp; 81.05.Je 相似文献
8.
Studying the surface properties of cubic boron nitride (c-BN) thin films is very important to making it clear that its formation mechanism and application. In this paper, c-BN thin films were deposited on Si substrates by radio frequency sputter. The influence of working gas pressure on the formation of cBN thin film was studied. The surface of c-BN films was analyzed by X-ray photoelectron spectroscopy (XPS), and the results showed that the surface of c-BN thin films contained C and O elements besides B and N. Value of N/B of c-BN thin films that contained cubic phase of boron nitride was very close to 1. The calculation based on XPS showed that the thickness of hexagonal boron nitride (h-BN) on the surface of c-BN films is approximately 0.8 nm. 相似文献
9.
F. Kokai M. Taniwaki M. Ishihara Y. Koga 《Applied Physics A: Materials Science & Processing》2002,74(4):533-536
We deposited amorphous thin films of boron carbide by pulsed laser deposition using a B4C target at room temperature. As the laser fluence increased from 1 to 3 J/cm2, the number of 0.25–5 μm particulates embedded in the films decreased, and the B/C atomic ratio of the films increased from
1.8 to 3.2. The arrival of melt droplets, atoms, and small molecular species depending on laser fluence appeared to be involved
in the film formation. In addition, with increasing fluence the nanoindentation hardness of the films increased from 14 to
32 GPa. We believe that the dominant factor in the observed increase in the films’ hardness is the arrival of highly energetic
ions and atoms that results in the formation of denser films.
Received: 23 March 2001 / Accepted: 1 July 2001 / Published online: 2 October 2001 相似文献
10.
Z.Y. Chen J.P. Zhao T. Yano T. Ooie 《Applied Physics A: Materials Science & Processing》2002,75(2):213-216
Raman characteristics of carbon nitride films synthesized by nitrogen-ion-beam-assisted pulsed laser deposition were investigated.
In addition to the D (disorder) band and G (graphitic) band commonly observed in carbon nitride films, two Raman bands located
at 1080–1100 and 1465–1480 cm-1 were found from our carbon nitride films. These two bands were well matched with the predicted Raman frequencies for βC3N4 and the observed Raman bands reported for carbon nitride films, indicating their relation to carbon-nitrogen stretching vibrations.
Furthermore, the relative intensity ratio of the two Raman bands to the D and G bands increased linearly with increasing nitrogen
content of the carbon nitride films.
Received: 30 October 2000 / Accepted: 5 February 2001 / Published online: 2 October 2001 相似文献
11.
Preparation of super-hard coatings by pulsed laser deposition 总被引:1,自引:0,他引:1
G. Reisse S. Weissmantel D. Rost 《Applied Physics A: Materials Science & Processing》2004,79(4-6):1275-1278
Amorphous diamond-like carbon (DLC) films and nanocrystalline cubic boron nitride (c-BN) films were prepared by pulsed laser deposition. DLC films with 80 to 85% sp3 bonds prepared at a laser fluence above 6 J/cm2 and a substrate temperature below 100 °C show high compressive stresses in the range of 8 to 10 GPa. Those stresses can be completely removed by means of pulsed laser annealing, allowing the preparation of DLC films with several-micrometre thickness. c-BN films were prepared with additional ion-beam bombardment at a substrate temperature of 250 °C. The properties of DLC and c-BN films deposited at high growth rates up to 100 nm/min are presented . PACS 81.15.Fg; 68.60.Bs: 62.40.+i 相似文献
12.
On the basis of the known reflection spectrum, we calculate a complete set of fundamental optical functions for cubic boron
nitride (c-BN) in the region of 2–23 eV. The integral spectrum of dielectric permeability is decomposed into 16 elementary
components. Three main parameters (maximum energy, half-width, and oscillator force) for each of the components are determined.
Using the well-known theoretical calculations for bands of boron nitride as the base we suggest a scheme of the nature of
these dielectric permeability components.
To whom correspondence should be addressed.
Udmurtiya State University, 1, Universitetskaya Str., Izhevsk, 426034, Russia:e-mail: sobolev@matsim.udmurtia.su. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 4, pp. 579–583, July–August, 1999. 相似文献
13.
J. Camarero V. Cros M.J. Capitán J. Álvarez S. Ferrer M.A. Niño J.E. Prieto L. Gómez J. Ferrón A.L. Vázquez de Parga J.M. Gallego J.J. de Miguel R. Miranda 《Applied Physics A: Materials Science & Processing》1999,69(5):553-557
Interlayer diffusion in epitaxial systems with a high energy barrier at the atomic steps – the so-called Ehrlich–Schwoebel
(ES) barrier – is strongly reduced. As a consequence of this, a continuous accumulation of roughness takes place during growth.
This undesirable effect can be corrected by using surfactant agents. We have studied the influence of the ES barrier on the
preparation of epitaxial films on Cu(111), and the surfactant effect of a monolayer of Pb.
Received: 21 April 1999 / Accepted: 17 August 1999 / Published online: 6 October 1999 相似文献
14.
Hetero-Epitaxial Diamond Single Crystal Growth on Surface of cBN Single Crystals at High Pressure and High Temperature
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We report a new diamond synthesis process in which cubic boron nitride single crystals are used as seeds, FesoNi20 alloy powder is used as catalyst/solvent and natural flake-like graphite is used as the carbon source. The samples are investigated using laser Raman spectra and x-ray diffraction (XRD). Morphology of the sample is observed by a scanning electron microscope (SEM). Based on the measurement results, we conclude that diamond single crystals have grown on the cBN crystal seeds under the conditions of high temperature 1230℃ and high pressure 4.8 GPa. This work provides an original method for synthesis of high quality hereto-semiconductor with cBN and diamond single crystals, and paves the way for future development. 相似文献
15.
Investigation of the thermal conductivity of diamond film on aluminum nitride ceramic 总被引:1,自引:0,他引:1
Y. Liao R.C. Fang Z.Y. Ye N.G. Shang S.J. Han Q.Y. Shao S.Z. Ji 《Applied Physics A: Materials Science & Processing》1999,69(1):101-103
Diamond films were successfully synthesized on aluminum nitride(AlN) ceramic substrates by hot-filament chemical vapor deposition
(HFCVD) method. The thermal conductivity of the diamond film/aluminum nitride ceramic (DF/AlN) composites was studied by photothermal
deflection (PTD) technique. It has reached 2.04 W/cm K, 73% greater than that of AlN ceramic. Compared with the measurement
of scanning electron microscopy (SEM) and Raman spectroscopy, the influence of diamond films on the thermal conductivity of
the composites was pointed out. The adhesion and the stresses were also studied. The unusual stability and very good adhesion
of the diamond film on AlN ceramic substrate obtained is attributed to the formation of aluminum carbide.
Received: 24 March 1998 / Accepted: 8 March 1999 / Published online: 5 May 1999 相似文献
16.
A. Lunk P. Bachem P. Scheible L. Ulrich 《Applied Physics A: Materials Science & Processing》2001,72(5):557-564
The development of in situ diagnostics of the most important species and reactions in the plasma and/or on the surface during
thin-film growth is one of the current topics in plasma-enhanced vapor deposition. In situ thin film diagnostic methods which
could be used in plasma processing are restricted due to the presence of electrons and ions. The advantages and disadvantages
of different applicable methods will be discussed. The spectroscopic in situ control of boron nitride film growth is presented
as an example of surface modification in low-temperature, low-pressure plasma processing. The growth of cubic and hexagonal
boron nitride is observed by polarized infrared reflection spectroscopy in absorption and ellipsometric configurations as
well as by single-wavelength ellipsometry in the visible spectral range. Modeling of the experimental results gives detailed
information on growth conditions and internal stress of the films.
Received: 8 August 2000 / Accepted: 12 December 2000 / Published online: 3 April 2001 相似文献
17.
Boron nitride (BN) nanotubes have been synthesized by evaporating a mixture of boron and gallium oxide in the presence of
ammonia gas. The synthesized BN nanotubes exhibit a well-crystallized concentric structure with diameters less than 30 nm,
and no carbon contamination or defects could be observed, while the BN nanotubes with large diameters usually show a number
of defects. Some BN nanohorn structures could also be observed in the product. The carbon-free growth of BN nanotubes was
explained based on the vapor–liquid–solid growth mechanism, and the catalytic activity of liquid gallium for BN one-dimensional
growth was also demonstrated.
Received: 16 April 2002 / Accepted: 25 May 2002 / Published online: 19 July 2002 相似文献
18.
The boron nitride (BN) films containing cubic boron nitride (c-BN) and hexagonal boron nitride (h-BN) were prepared by radio frequency a ssisted thermal filament chemical vapor deposition. The stress and strain in BN films were investigated by X-ray diffraction analysis using the sin2 ψ method. The results showed that both c-BN and h-BN in the same film have similar values of elastic strain, however, the compressive stress in c-BN is much greater than that in h-BN for the same film. Both stress and strain gradually decre ased with the increase of substrate temperature (Ts). The effective stress in the films calculated by the effective stress model increased with the increase of Ts. Furthermore, the dependence of effective stress in the films on Ts was also investigated. 相似文献
19.
用X射线衍射技术、红外吸收光谱、扫描电子显微镜、X射线光电子能谱对热丝辅助射频等离子体化学汽相沉积法制备的立方氮化硼(c-BN)薄膜的生长特性和粘附性进行了研究.改变生长条件,在Si、不锈钢和Ni衬底上沉积c-BN薄膜,进而研究了c-BN薄膜的质量和生长条件与衬底之间的关系.实验发现,Ni衬底上生长的薄膜c-BN含量较高,且粘附性好.当Si衬底上溅射一层Ni过渡层,再生长c-BN薄膜,薄膜中c-BN含量提高,与Si衬底的粘附性也显著增强.
关键词: 相似文献
20.
Abstract FT-IR Spectroscopy have been used for identifying both the structure of BN and the intensity of the compressive stress in cubic boron nitride (c-BN) film prepared by a unbalanced of (13.56 MHz) magnetron sputtering of a hexagonal boron nitride target in a mixture argon and nitride discharge. A T(temperature) - V(negative bias) phase diagram was obtained using the phase structure identify by IR spectra. Comparing the reflection infrared spectra (RIR) with the transmission infrared spectra (TIR) measured from same c-BN film, it is firstly found that RIR peak position of c-BN is lower than TIR peak position of c-BN, this means that the compressive stress on the surface layer of c-BN film is smaller than that inside c-BN film, may be this is the reason why thicker c-BN film can not be synthesized. A higher IR peak position of 1064 cm?1 and a lower peak position 1004.7 cm?1 were detected from a broken and partly peeled off c-BN film. The peak position of 1064 cm?1 agrees with that of bulk c-BN at 1065 cm?1 which was synthesized at high temperature and high pressure, while the peak position of 1004.7 cm?1 accords well with the result calculated (1004 cm?1) by Wentzcovitch and it may be closes to that of the stress free value of c-BN. Using the result measured by Ulrich, the shift rate of IR peak position of c-BN in the films is about 3.8 cm?1/Gpa to be obtained. 相似文献