Thin nanocrystalline

Fig. 26 (a) Nanocrystalline film of Au formed al the toluene-water interface, (b) When dodecanethiol is added to the toluene layer, the film breaks up, forming an organosol of Au, (c) Au hydrosol obtained when mercaptoundecanoic acid is added to waler. TEM images of the ultra-thin nanocrystalline Au films obtained at the liquid-liquid interface after 24 h (d) 30 "C, (e) 45 °C, (0 60 °C and (g) 75 °C. The histograms of particle size distribution are shown. The scale bars correspond Lo 50 nm. A high-resolution image of an individual particle is shown at the center. Reprinted with permission from V. V. Agrawal, G. U. Kulkarni and C. N. R. Rao, J. Phys. Chem. B, 2005, 109, 7300. C J 2005, American Chemical Sociely. 

FIGURE 2. TEM images of the ultra thin nanocrystalline Au films obtained at the liquid-liquid interface after 24 h at (a) 30, (b) 45, (c) 60, and (d) 75 °C. Histograms of particle size distribution are shown as insets. The scale bars correspond to 50 nm. A high-resolution Image of an individual particle is shown at the center. Reproduced from ref 24. Copyright 2005 American Chemical Society. 

Fang DZ, Striemer CC, Gaborski TR, McGrath JL, Fauchet PM (2010a) Methods for controlling the pore properties of ultra-thin nanocrystalline silicon membranes. J Phys Condens Matter 22(454134) 1-7... 

W. (2003) Efficient third-harmonic generation in a thin nanocrystalline film of ZnO. Applied Physics Letters, 83, 3993. 

Sarangi, S. N. and Sahu, S. N. (2004). CdSe nanocrystalline thin films composition, structure and optical properties. Physica E, 23,159-167. 

Various microstructures and configurations are possible for useful solid materials, including bulk single crystals and epitaxial layers, polycrystalline articles or thin films with controlled grain size (including micro- and nanocrystalline... 

Thin film coatings of nanocrystalline semiconductors, as collections of quantum dots (QD or Q-dot) attached to a solid surface, resemble in many ways semiconductor colloids dispersed in a liquid or solid phase and can be considered as a subsection of the latter category. The first 3D quantum size effect, on small Agl and CdS colloids, was observed and correctly explained, back in 1967 [109]. However, systematic studies in this field only began in the 1980s. 

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. 

Lipowsky, P. Jia, S. Hoffmann, R. C. Jin-Phillipp, N. Y. Bill, J. Ruhle, M. 2006. Thin film formation by oriented attachment of polymer-capped nanocrystalline ZnO. Zeitschrift fur Metalllcunde 97(5) 607-613. 

Pathan, H. M. Sankapal, B. R. Desai, J. D. Lokhande, C. D. 2003. Preparation and characterization of nanocrystalline CdSe thin films deposited by SILAR method. Mater. Chem. Phys. 78 11-14. 

Ubale, A. U. Dhokne, R. I Chikhlikar, P. S. Sangawar, V. S. Kulkanari, K. 2006. Characterization of nanocrystalline cadmium telluride thin films grown by successive ionic layer adsorption and reaction (SILAR) method. Bull. Mater. Sci. 29 165-168. 

Patil, R. S. Lokhande, C. D. Mane, R. S. Pathan, H. M. Oh-Shim, J. Sung-Hwan, H. 2006. Successive ionic layer adsorption and reaction (SILAR) trend for nanocrystalline mercury sulfide thin films growth. Mater. Sci. Eng. B 129 59-63. 

Bose, F. Ayral, A. Albouy, P. A. Guizard, C. 2003. A simple route for low-temperature synthesis of mesoporous and nanocrystalline anatase thin films. Chem. Mater. 15 2463-2468. 

Choi, S. Y. Mamak, M. Coombs, N. Chopra, N. Ozin, G. A. 2004. Thermally stable two-dimensional hexagonal mesoporous nanocrystalline anatase, meso-nc-Ti02 Bulk and crack-free thin film morphologies. Adv. Fund. Mater. 14 335-344. 

B. Fausett, M. C. Granger, M.L. Hupert, J. Wang, G. M. Swain, D. M. Gruen, The electrochemical properties of nanocrystalline diamond thin-films deposited from C60/Argon and Methane/Nitrogen gas mixtures, Electroanal., vol. 12, pp. 7-15, 2000. 

This technique yields a catalyst composed entirely of metal nanoparticles or nanocrystalline thin film, and it allows for control of size and distribution while eliminating the need for a dispersing and supporting medium. The obtained electrodes contained as little as 0.017 mg Pt/cm and performed as well as standard E-TEK electrodes (Pt loading 0.4 mg/cm ). The PLD technique may be of special interest as an alternative to the sputtering process in the production of micro fuel cells. 

Las but not least, sample preparation is also an important issue. If we want to examine nanocrystalline powder samples. The grain size must be just a few nanometers, the layer, formed by these nanocrystals must be as thin as possible (to minimize dynamic difiraction), continuous and self-supporting. In many cases not all these requirements are fulfilled simultaneously. The nanocrystalline material to be studied is frequently present on a thin supporting carbon layer. In such cases peak decomposition can not yield an acceptable fit unless the presence of the amorphous material (in the form of a few diffuse rings) is taken explicitly into account in the model to be fitted. The size of the background is also affected by scattering in such a carbon support. 

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