Nanocrystalline diamond films

Recently Butler et al. [4] reported the deposition of nanocrystalline diamond films with the conventional deposition conditions for micrometer-size polycrystalline diamond films. The substrate pretreatment by the deposition of a thin H-terminated a-C film, followed by the seeding of nanodiamond powder, increased the nucleation densities to more than 10 /cm on a Si substrate. The resultant films were grown to thicknesses ranging from 100 nm to 5 fim, and the thermal conductivity ranged from 2.5 to 12 W/cm K. 

Ku, C. H. and Wu, J. J. (2004), Effects of CCI4 concentration on nanocrystalline diamond film deposition in a hot-filament chemical vapor deposition reactor. Carbon, 42(11) 2201-2205. 

Yoshikawa, H., Morel, C. and Koga, Y. (2001), Synthesis of nanocrystalline diamond films using microwave plasma CVD. Diam. Relat. Mater., 10(9-10) 1588-1591. 

Fig. 5 Plan view (a) SEM and (b) TEM micrographs of nanocrystalline diamond film.

This work is supported by the U. S. Department of Energy, under Contract W-31-109-Eng-38. The author thanks his research collaborators and students who participated in the reparation, testing, and characterization of the nanocrystalline diamond films discussed in this chapter. 

Gruen and co-workers[90] and Fausett et al. [81] also discussed about manufacturing smoother diamond films by modifying the growth conditions, but these films usually contain nondiamond intergranular phases. They found that nanocrystalline diamond films produced from CgolAr gas mixtures demonstrated basic electrochemical properties that were similar to... 

Raman spectroscopy gave structural characterisation of nanocrystalline diamond films formed by pulsed laser deposition in an oxygen atmosphere.300 Raman and IR spectra were used to follow diamond deposition on mirror-polished Si single crystal substrates.301 Nanocrystalline diamond spheres were also characterised by Raman spectroscopy.302... 

Figure 6.21 Mechanism for the deposition of nanocrystalline diamond films.

Nanocrystalline diamond films also frequently show remarkable conductivity that is primarily attributable to the large portion of atoms situated in grain boundaries. The sp -hybridized carbon atoms generate electronic states within the diamond s bandgap. These lead, for instance, to the so-caHed hopping conductivity, that is, a conductance arising from a successive hopping from one state to the next. 

Grnen DM. Nanocrystalline diamond films. Annn Rev Mater Sci 1999 29 211-59. 

Askari SJ. Tribological characteristics of nanocrystalline diamond films grown on titanium. Surf Eng 2009 25 482-6. 

Palnitkar UA, et al. Adhesion properties of nitrogen ion implanted nltra-nanocrystalline diamond films on sihcon substrate. Diamond Relat Mater 2008. 

Lin T, et al. Compositional mapping of the argon - methane - hydrogen system for polycrystaUine to nanocrystalline diamond film growth in a hot-filament chemical vapor deposition system Appl Phys Lett 2000. 

Gmen DM, et al. Characterization of nanocrystalline diamond films by corelevel photoabsorption. Appl Phys Lett 1996. 

Tadjer Ml, et al. Nanocrystalline diamond films as UV-semitransparent Schottky contacts to 4H-SiC. Appl Phys Lett 2007. 

Xu Z, et al. A study of polyaniline deposited nanocrystalline diamond films for glucose detection. J Nanosci Nanotechnol 2007. 

Gajewski W, Achatz P, Williams OA, Haenen K, Bustarret E, Stutzmann M, Garrido JA (2009) Electronic and Optical Properties of Boron-Doped Nanocrystalline Diamond Films. J. phys. rev. B 79 045206. 

Figure 6 shows Hall measurement data for a series of boron-doped nanocrystalline diamond films deposited with different levels of B2H6 added to the source gas mixture. Measurements of the carrier concentration and mobility were made at different temperatures up to about 500°C. At room temperature, the carrier concentration increases and the hole mobility decreases as B2H6 added to the source gas mixture with values in the range of 10 -10 cm and 10-100 cm /V-s, respectively. The carrier concentration and the doping level increase proportionally with B2H6 added. 

Boron-doped nanocrystalline diamond films have recently been produced and evaluated as electrodes [115]. The films consist of clusters of diamond grains, 100 nm in diameter, and possess an rms surface roughness of 34 nm over a 5 x 5 pm area. The individual diamond grains are approximately 10 15 nm in diameter, as determined by TEM. Films with a thickness ranging from 0.5 to 4 pm are deposited by microwave-assisted eVD using a CH4/H2/Ar gas mixture (1/4/95%). B2H6, diluted... 

Gruen DM (1999) Nanocrystalline Diamond Films. Annu Rev Mater Sci 29 211. 

Barek J, Jandova K, Peckova K et al (2007) Voltammetric determinatiim of aminobiphcmyls at a boron-doped nanocrystalline diamond film electrode. Talanta 74 421-426... 

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