Epitaxial synthesis

Physics and chemistry researchers approach III—V synthesis and epitaxial growth, ie, growth in perfect registry with the atoms of an underlying crystal, differently. The physics approach, known as molecular beam epitaxy (MBE), is essentially the evaporation (14—16) of the elements, as illustrated in Figure 4. The chemistry approach, organometaUic chemical vapor deposition (OMCVD) (17) is exemplified by the typical chemical reaction ... 

Cuomo JJ, Gambino RJ (1968) The synthesis and epitaxial growth of GaP by fused salt electrolysis. J Electrochem Soc 115 755-759... 

A variety of compound semiconductors have been successfully prepared by this technique. Much of the work concerning ECALE has been concentrated on the deposition of CdTe on An substrates. Notwithstanding the inherent problems of the system (for instance, a 10% lattice mismatch), the formation of CdTe epitaxial layers became a model example of ECALE synthesis. In their pioneering studies, Stickney and co-workers [27, 28] have focused on the deposition of the compound on... 

The ECALE synthesis of V-VI (V Sb, Bi) compounds has been attempted in a few works. Antimony telluride, Sb2Te3, nanofilms with a homogeneous microstructure and an average size of about 20 nm were formed epitaxially on a Pt substrate [61]. The optical band gap of these films was blue-shifted in comparison with that of the bulk single-crystal Sb2Tc3 compound. 

Gorer S, Ganske JA, Hemminger JC, Penner RM (1998) Size-selective and epitaxial electrochemical/chemical synthesis of sulfiir-passivated cadmium sulfide nanocrystals on graphite. J Am Chem Soc 120 9584-9593... 

Electrocatalytic activity of supported metal particles has been investigated on surfaces prepared in an ultrahigh vacuum (UHV) molecular beam epitaxy system (DCA Instruments) modified to allow high throughput (parallel) synthesis of thin-film materials [Guerin and Hayden, 2006]. The system is shown in Fig. 16.1, and consisted of two physical vapor deposition (PVD) chambers, a sputtering chamber, and a surface characterization chamber (CC), all interconnected by a transfer chamber (TC). The entire system was maintained at UHV, with a base pressure of 10 °mbar. Sample access was achieved through a load lock, and samples could be transferred... 

Fig. 2.2 Bottom-up synthesis methods, (a) Catalytic vapor deposition (b) epitaxial growth from SiC.

PbOj anode, 40 155-156 oxygen evolution, 40 109-110 PCE, catalytic synthesis of, l,l,l-trifluoro-2,2-dischloroethane, 39 341-343 7t complex multicenter processes of norboma-diene, 18 373-395 PdfllO), CO oxidation, 37 262-266 CO titration curves, 37 264—266 kinetic model, 37 266 kinetic oscillations, 37 262-263 subsurface oxygen phase, 37 264—265 work function and reaction rate, 37 263-264 Pd (CO) formation, 39 155 PdjCrjCp fCOljPMe, 38 350-351 (J-PdH phase, Pd transformation, 37 79-80 P-dimensional subspace, 32 280-281 Pdf 111) mica film, epitaxially oriented, 37 55-56... 

M. J. McCollum and G. E. Stillman, High Purity InP Grown by Hydride Vapor Phase Epitaxy T. Inada and T. Fukuda, Direct Synthesis and Growth of Indium Phosphide by the Liquid Phosphorous Encapsulated Czochralski Method O. Oda, K. Katagiri, K. Shinohara, S. Katsura, Y. Takahashi, K. Kainosho, K. Kohiro, and R. Hirano, InP Crystal Growth, Substrate Preparation and Evaluation... 

Quantum dots are the engineered counterparts to inorganic materials such as groups IV, III-V and II-VI semiconductors. These structures are prepared by complex techniques such as molecular beam epitaxy (MBE), lithography or self-assembly, much more complex than the conventional chemical synthesis. Quantum dots are usually termed artificial atoms (OD) with dimensions larger than 20-30 nm, limited by the preparation techniques. Quantum confinement, single electron transport. Coulomb blockade and related quantum effects are revealed with these OD structures (Smith, 1996). 2D arrays of such OD artificial atoms can be achieved leading to artificial periodic structures. 

The hybrid electrochemical/chemical synthesis of epitaxially oriented CdS nanocrystallites-size selectively on graphite surface was described by Anderson etal. [164]. A schematic diagram of such synthesis is presented in Fig. 6. 

In what form do you want the product to be You might choose, for example, vapour phase epitaxy because an application requires a single crystal. Alternatively, you might choose a particular method, such as the precursor method or hydrothermal synthesis, because you need a homogeneous product. 

In a new study of a series of binary Cu-ZnO catalysts a correlation was found between methanol synthesis activity and strain in the Cu metal phase.619 Structural defects of Cu resulting from ZnO dissolved in Cu, incomplete reduction, or epitaxial orientation to ZnO are believed to bring about strain, which modifies the Cu surface and, consequently, affects the catalytic activity. The higher amount of water formed in methanol synthesis from a C02-rich feed compared to a CO-rich feed brings about significant catalyst deactivation by inducing crystallization of both Cu and ZnO.620... 

In standard csd processing the aim is to produce dense polycrystalline, columnar or even epitaxial thin films. The above described csd precursor solution did not lead to satisfactory dense PbTi03 thin films. Nevertheless, the opposite of dense films, i.e. separated nanostructures are of great interest for studying intrinsic size effects. For this reason the before introduced PbTi03 precursor synthesis was modified. The flow chart in Figure 18.7 displays the main modifications of the basic csd route. 

Originated in the late 1970 s, ALE has become a widely used synthesis route for thin epitaxial layers. Many ALE coated materials are produced commercially today. 

A general requirement for the synthesis of CS NCs with satisfactory optical properties is epitaxial type shell growth. Therefore an appropriate band alignment is not the sole criterion for choice of materials but, in addition, the core and shell materials should crystallize in the same structure and exhibit a small lattice mismatch. In the opposite case, the growth of the shell results in strain and the formation of defect states at the core-shell interface or within the shell. These can act as trap states for photogenerated charge carriers and diminish the fluorescence QY.95 The structural parameters of selected semiconductor materials are summarized in Table 5.1. 

K. Radermacher, S. Mantl, Ch. Dieker, H. Ltith, C. Freiburg. Growth kinetics of iron silicides fabricated by solid phase epitaxy or ion beam synthesis // Thin Solid Films.- 1992.-V.215, No.l.- P.76-81. 

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