Growth of p-type InP single crystals by the temperature gradient method

P-type InP single crystals doped with zinc or cadmium have been prepared from a solution using indium as a solvent in which a temperature gradient was maintained for the transport of the InP solute. The average growth rate was between 1.1 and 3.0 mm/week. The room temperature hole concentration of the crystals obtained was in a range of 10¹⁷ to 10¹⁸ cm^-3. The distribution coefficients of zinc and cadmium were 0.8 and 0.004, respectively. The temperature gradient method makes it possible to dope the crystals with volatile impurities in a controlled manner.     

Growth of single crystals of quasicrystalline phases

To study the mechanical and physical properties of quasicrystals, single-crystal samples of large size (several centimeters) are necessary. However, obtainment of such single crystals meets a number of difficulties related to the peritectic character of melting of quasicrystalline compounds, high volatility and oxidizability of the initial components, low growth rate in aperiodic directions, and metastability of the most quasicrystalline structures. In this study, criteria for stable growth of quasicrystalline phases have been determined. The growth mechanisms of icosahedral and decahedral single crystals are described and experimental techniques of single-crystal growth are reviewed.     

Growth mechanism of stearic acid single crystals

Micro-morphological observation of the growth patterns on the (001) surfaces of large single crystals of stearic acid grown from solution under moderate growth conditions was carried out by optical and electron microscopy. Two typical growth features, namely, growth spiral steps and two-dimensional (2-D) nucleation-like steps, were identified optically. Then, these patterns were observed in more detail by the replica method of electron microscopy and it was found that the steps are usually two to four times the length of the bimolecular growth unit. These growth units also revealed spiral growth and 2-D nucleation growth patterns.     

Growth of GaSe and GaS single crystals

The paper describes principal manipulations to prepare single crystals of GaSe and GaS. A new simple method of synthesis with single‐zone heating furnace is proposed. Growth of crystals was performed by modified Bridgman method with the use of rotating heat field. Raman and optical depth spectra show high structural and optical quality of obtained crystals. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Growth and morphology of p-terphenyl single crystals

The results of a preliminary investigation of the growth and morphology of p-terphenyl crystals grown by sublimation and by solvent evaporation methods are reported. It was observed that lozenge–shaped (001) crystal plates are obtained from xylene and benzene solution while dendritic crystals by sublimation. Crystallographic orientation of the plates and microscopic observations of as-grown crystal surfaces are also described.     

Growth and properties of single crystals of FeTi

A Single crystal of FeTi with a diameter of ca 34 mm and a length of ca 48 mm has been grown from a quasi-stoichiometric melt with an excess of 1% titanium employing the Bridgman technique. Experiments with the Czochralski technique were not successful. The only crucible material sufficiently resistent against reaction with the melt is electrographite. Elastic and thermoelastic constants were determined by means of ultrasonic methods. FeTi and α iron possess a similar bulk compressibility, thermal expansion, and thermoelastic constants. The longitudinal elastic resistance c₁₁ of FeTi supersedes that of α iron by an amount of ca 30%.     

Growth of doped-halide single crystals for infrared windows

Single crystals of KCl doped with RbCl have been grown by the Czochralski and Bridgman techniques. Czochralski crystals were grown in air, using platinum crucibles and Bridgman crystals were grown in a Trans-Temp glass furnace in air and also under a reactive atmosphere of CCl₄ in argon. This reactive atmosphere process (RAP) is known to greatly reduce impurities, such as hydroxyl ions, which degrade optical quality. A series of KCl-RbCl-SrCl₂ single crystals have been grown to stabilize microstructure. Some optical absorption and mechanical strength data is presented. An alternative approach to increase halide material strength is to hot-forge a single crystal under temperature and pressure sufficient to cause pressure-induced recrystallization (PIR). Hot-forging techniques to produce high-strength IR windows without degrading optical transmission are given.     

Growth and characterization of succinic acid single crystals

Single crystals of ferroelectric succinic acid were grown from aqueous solution by low temperature solution growth technique. The cell parameters and space group are found using powder X‐ray diffraction analysis. The presence of the functional groups has been estimated qualitatively by FTIR analysis. The UV‐Visible spectrum shows the cut‐off wavelength at 240 nm. The thermal stability of the crystal was studied by TG/DTA. The dielectric constant of the crystal studied as a function of frequency shows the pyroelectric property. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Growth of NiAl shape memory alloy single crystals

As a potential candidate of high temperature Shape Memory Alloy (SMA), inter metallic compound NiAl has been studied for more than 30 years. In order to understand better the mechanism of the Shape Memory Effect(SME) in β -NiAl phase, its bulk single crystal have been prepared with an improved magnetic levitation cold crucible Czoehralski(CZ) technique in our lab. The crystal growth procedure and the β -NiAl phase stability are discussed in this paper.     

Growth and characterization of mercurous chloride single crystals

Mercurous chloride was purified by repeated sublimation using multichamber distillation column. Single crystals were grown by Physical Vapour Transport technique. During the process of purification of the material, very interesting habit modifications like dendrites and needles were observed. Vickers hardness tests were carried out on the (110) plane of the crystal for different orientations of the indentor. The shape of the impressions for different orientations of the indentor reveals the non-cubic structure of the plane. No structural phase transition in mercurous chloride was observed in calorimetry and optical studies.     

Growth and characteristics of HgGaInS4 single crystals

Single crystals of the HgGaInS₄ layered compound were grown by the iodine transport technique. Results of their optical, photoelectric, and radiative properties' study are presented. The band gap and the binding energy of holes on the sensitizing centres were determined to be E_g = 2.41 eV and E_a = 0.2 eV, respectively. A presence of quasi-continuously distributed states was stated which are responsible for the exponential segment of the absorption edge and which take part in the radiative recombination.     

Growth and characterization of single crystals of KDP family

This contribution reports on the growth and characterization of single crystals of the KDP family, using the example of DKDP for display devices applications. The emphasis is put on all aspects common to most of the crystals regarding the solution preparation, the growth kinetics and the nature and origin of crystallographic imperfections. In particular, the dramatic role of the seeding step and the hydrodynamics are stressed. Finally, it is shown that the combination of X-ray topography, electroding decoration and autoradiography techniques is a powerful tool for the assessment of optimized growth conditions.     

Growth of single crystals of potassium chloride from gels

The growth of single crystals of potassium chloride (KCl) in silica gels upto 3 × 3 × 3 mm³ in size is described. To crystallize KCl incorporated in the gel, hydrochloric acid has been used to crystallize the KCl in the gel media. The crystalline perfection has been studied by the chemical etch pit technique.     

Growth and characterisation of gadolinium samarium oxalate single crystals

Single crystals of Gadolinium Samarium Oxalate (GSO) are grown by gel method. The crystals are pale yellowish in colour. Morphology and size of the crystals are found to depend on pH of the medium, gel density, concentration of the reactants and acidity of the feed solution. The crystallinity of the grown sample was confirmed by X‐ray diffraction studies and the lattice parameters were determined. X‐ray diffractogram shows well defined peaks. IR spectrum confirms the presence of water molecules and carboxylic group. EDAX analysis confirms the presence of Gd and Sm in the sample. The thermal decomposition behaviour of the crystal was analysed using TGA and DTA studies. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Growth and etching of anhydrous diglycine sulfate single crystals

Single crystals of anhydrous diglycine sulfate are grown at constant temperature by evaporation method. The crystals are grown at various temperatures and their growth rate is determined. A chemical etchant for dislocation studies is reported. The perfection of the crystals grown at various temperatures has been studied using etching technique. It is found that the crystals contained inclusions of the mother liquid. The crystals grown below 28° are almost free of inclusions and the dislocation density is also low.     

Growth and morphological study of copper oxide single crystals

Experiments on the growth of CuO single crystals by crystallization from flux in the CuO-Bi₂O₃-PbO-PbF₂, CuO-Bi₂O₃-Li₂O, CuO-Bi₂O₃-B₂O₃, CuO-BaO-Y₂O₃, and CuO-MO_x systems (M = P, V, or Mo) have been performed. The best results were obtained in crystallization in the CuO-Bi₂O₃-PbF₂ system: prismatic single crystals of platelet-and needlelike or isometric habit with dimensions up to 1 × 10 × 10, 1 × 1 × 20, or 6 × 6 × 8 mm, respectively, have been grown. The CuO crystals show polysynthetic twinning in the form of numerous alternating light and dark bands bound by systems of parallel straight lines on the {110} and {111} faces. A possible model of twinning associated with the Cu₂O → CuO transformation is considered.