Ternary crystal growth

A lot of experimental efforts have been dedicated by various groups to develop the ternary crystal-growth technology. Below we briefly summarize the methods used and their Hmitations for large-scale ternary-crystal production. 

Low-temperature solvents are not readily available for many refractory compounds and semiconductors of interest. Molten salt electrolysis is utilized in many instances, as for the synthesis and deposition of elemental materials such as Al, Si, and also a wide variety of binary and ternary compounds such as borides, carbides, silicides, phosphides, arsenides, and sulfides, and the semiconductors SiC, GaAs, and GaP and InP [16], A few available reports regarding the metal chalcogenides examined in this chapter will be addressed in the respective sections. Let us note here that halide fluxes provide a good reaction medium for the crystal growth of refractory compounds. A wide spectrum of alkali and alkaline earth halides provides... 

Unfortunately, the initial promise of this approach was followed by disappointment, as the ternary sulfide catalyst rapidly lost activity with extended use. XPS analyses of used catalysts showed that Ru catalyzed the reduction of Mo, which led eventually to crystal growth of the MoS2, which resulted in loss of activity. Perhaps other supports having higher surface areas or... 

Metallic carbides, nitrides, and oxides are used industrially in many applications their physical properties are also of intrinsic interest. This section pinpoints various preparative techniques and reviews methods of crystal growth for this group of compounds. More detailed discussion is found in the reviews cited and in the references therein. The discussion is confined to binary compounds, M Xi, (M is a cation X = C, N, or O a and b are simple integers) that display metallic properties the very numerous ternaries MoMcXj, (M, M being different cations) cannot be described in this brief presentation. 

From the chemical point of view it seems to be of particular interest that further (metastable) tellurium subhalides can be obtained by hydrothermal syntheses in acid solutions. In the hydrothermal work on the crystal growth of arsenic telluro-iodides a pure binary tellurium subiodide with the composition Tcsl was obtained as well as a ternary phase with only small amounts of arsenic (AsT Ij The composition Tejl was checked by chemical as well as energy-dispersive X-ray analysis. Crystals of the new tellurium subiodide are shown in Fig. 43 a crystal structure analysis failed because the quality of the crystals was not suitable for single crystal investigation. During annealing of the subiodide a stable phase combination a-Tel -H Te was formed which indicated the metastable character of TesL... 

At the present study the diffusion-controlled growth process from the ternary system was modelled by the Maxwell-Stefan equations. The estimation methods of the required parameters in the model were shown. The model was evaluated from single crystal growth measurements in the ternary system. The results showed that experimental and predicted growth rates were within acceptable agreements. 

Voda, M., Al-Saleh, M., Lobera, G., Baida, R., Fernandez, J., 2004. Crystal growth of rare-earth-doped ternary potassium lead chloride single crystals by the Bridgman method. Opt. Mater. 

Several of the structure types found for the halides are observed for other important monovalent anion systems such as the trihydroxides and trihydrides and derivatives of these structures are observed for a variety of ternary phases (Haschke, 1975c and 1976b). Other monovalent anions, Y, are accommodated in PuBt3- and UCh-type RX3 phases by replacement of the X layers. The resulting RX2Y compositions are structural derivatives of the parent trihalide structures. These observations and the phase equilibria and crystal growth habits of the ternary derivatives support the conclusion that several of the trihalide structures are accurately described by alternation of RXj and X layers, but additional work is clearly necessary. 

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