Travelling Solvent Techniques

Single crystal growth by the traveling solvent technique: A review

“…The main variant of the traveling solvent growth uses the traveling heater method (THM), whereby a single crystal is grown in a vertically held container by translating a heated sector and thereby slowly moving a molten zone of different composition (solvent) through a polycrystalline charge of the desired crystal. Despite the commonly used term 'traveling heater method', movement of the solvent zone is not necessarily provided by a mechanical movement of a heater, rather the heater is sometimes held stationary and the container is moved in relation to it [10][11]. A less used variant of the traveling solvent techniques is the so-called traveling solvent method (TSM) for which the solvent zone thickness is typically smaller than THM [10].…”

“…The 'traveling' solvent technique has certain similarities to the flux technique in that crystals of a range of materials can be grown at temperatures below their melting point making it suitable for both peritectic and congruently melting compounds, and crystals of solid solutions of homogeneous composition [7][8][9][10][11].…”

“…In addition to the advantage of growth at lower temperatures, the crystals grown using this technique are generally larger in size than flux grown crystals via spontaneous nucleation because the traveling solvent technique is in effect a zone melting process in which the existence of a sharp temperature gradient profile along the sample leads to directional solidification. Furthermore, this melt zoning process helps to grow higher purity single crystals since the solvent and other impurities are moved away from the growing crystal [10][11][12]. Crystals developed from solution (rather than from the pure melt or the vapor) using the travelling solvent are also reported to have more perfect crystalline structures with lower dislocation densities due to a lower solution enthalpy [10].…”

“…Furthermore, this melt zoning process helps to grow higher purity single crystals since the solvent and other impurities are moved away from the growing crystal [10][11][12]. Crystals developed from solution (rather than from the pure melt or the vapor) using the travelling solvent are also reported to have more perfect crystalline structures with lower dislocation densities due to a lower solution enthalpy [10].…”

“…Thus, in order to grow higher quality crystals it is vital to study the technique and its relevant experimental variations in detail to attain better control and greater understanding of the growth conditions. The main aim of this article, therefore, is to review the published information pertaining to the various aspects of traveling solvent crystal growth and its associated experimental parameters, while the discussion employs concepts covered in textbooks on bulk crystal growth [1,11], crystal growth theory and techniques [10], and zone refining [12]. In addition, the use of optical heating is discussed in relation to the traveling solvent technique while current experimental practice is illustrated by describing the crystal growth of Tl 5 Te 3 , Cd 3 As 2 , and FeSc 2 S 4 (using Te, Cd and FeS fluxes, respectively).…”