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• Single-crystal X-ray diffraction analysis of the Ca 9 Eu(PO 4) 7 and Ca 9 Er(PO 4) 7 phosphors were performed. Eu predominantly resides at medium-sized M1 and M2 sites, with some distribution at the larger M3 sites. In contrast, Er prefers the smallest M5 site, but it also significantly occupies the M1 and M2 sites. Anomalous X-ray scattering (AXS) measurements at the Eu L III and Er L III absorption edges demonstrated an energy dependence that corroborates the Eu and Er distributions obtained from single-crystal X-ray diffraction. The structures of Ca 9 Eu(PO 4) 7 and Ca 9 Er(PO 4) 7 phosphors were analyzed using single-crystal X-ray diffraction. Most Eu ions reside at the medium-sized M1 and M2 sites, with a small amount occupying the M5 site. In contrast, the smaller Er ions favor the smallest M5 site. This study also demonstrates the use of anomalous X-ray scattering measurements at the Er L III and Er L III -edges. The energy dependencies observed in the scattering factors for Ca 9 Eu(PO 4) 7 and Ca 9 Er(PO 4) 7 confirmed the preferred distribution of Eu and Er. Because this anomalous X-ray scattering method leverages the unique anomalous dispersion terms of each element, this advanced technique, coupled with a synchrotron radiation source, is suggested to be a powerful method for distinguishing near-neighbor rare-earth elements in solid-state phosphors. [ABSTRACT FROM AUTHOR]

• Li-deficient Li 0.95 FeAs crystals were grown by high-pressure self-flux method. • Grown crystals exhibit plate-like shape with dimensions up to 0.7 × 0.7 × 0.15 mm3. • For Li-deficient composition Li 0.95 FeAs a critical temperature T c is 16 K. Single crystals of LiFeAs were successfully grown by a self-flux method using the cubic anvil high-pressure and high-temperature technique. The reaction took place in a closed boron nitride crucible at a pressure of 1 GPa and a temperature of 1050 °C. The grown crystals, retrieved from solidified lump, exhibit plate-like shapes with sizes up to 0.7 × 0.7 × 0.15 mm3. Single-crystal x-ray diffraction refinement confirmed the high structural perfection of the grown crystals [space group P 4/ nmm , No 129, Z = 2, a = 3.77370(10) Å, c = 6.3468(6) Å, and V = 90.384(9) Å3] with the presence of a small deficiency on the Li site. The refined chemical composition of the produced crystals is Li 0.95 FeAs. Temperature-dependent magnetization measurements revealed bulk superconductivity with a superconducting transition T c = 16 K. A comparative analysis of LiFeAs, Li 1- x FeAs, and Li 1- y Fe 1+ y As systems reveal that superconductivity is less sensitive to the Li deficiency, although it may completely disappear in the presence of both Fe excess and Li deficiency. [ABSTRACT FROM AUTHOR]

• The congruent CNGG shows non-stoichiometric features, suggesting the existence of some vacancies at cation sites. • Limited information is available regarding fine structure of CNGG-type crystals with respect to the cation distribution. • The distribution of Nb is a key factor in determining the structure of CNGG. • Single-crystal anomalous X-ray scattering experiments suggested an ordered distribution of Nb at the octahedral site. Single-crystal anomalous X-ray scattering (AXS) experiments were conducted to investigate the cation distribution of calcium–niobium–gallium garnet (CNGG). AXS measurements suggested an ordered distribution of Nb at the octahedral site, and further structural refinement allowed us to obtain the structural formula Ca 3 Nb 1.703(0) Ga 3.162(2) O 12. Ca was only located in the dodecahedral site, while Ga was distributed in the octa- and tetrahedral sites. The tetrahedral site had a significant number of vacancies at a ratio of one vacancy per unit cell, and the Nb/Ga occupation ratio at the octahedral site results in non-stoichiometric chemical composition of CNGG and its unique broad absorption wavelength. The findings of this study can contribute to device fabrication, property optimization, and quality control processes related to CNGG. [ABSTRACT FROM AUTHOR]

• GaAsN/GaAs-superlattice films fabricated by atomic layer epitaxy. • Post annealing for N-distribution modulation. • Relationship between the N distribution and electrical properties. • N-distribution homogenization correlated with N-induced scattering-center reduction. The effects of nitrogen (N) distribution on the electrical properties of GaAsN films were evaluated by intentionally changing the N distribution using atomic layer epitaxy (ALE) and post-annealing. The N distribution was controlled in the growth direction by growing superlattice (SL) thin films repeatedly growing 1 GaAsN layer and 0, 3, and 5 layers of GaAs by ALE. These films were referred to as (1:0), (1:3), and (1:5), respectively. To change the N distribution in the same thin film, N atoms were diffused by post-annealing. Changes in N distribution were evaluated by X-ray diffraction as changes in GaAsN superstructure. N atoms diffused from GaAsN layers to the adjacent layers in (1:3) films annealed above 750 °C, while they remained stable in those of (1:5) films annealed at temperatures up to 850 °C. The carrier mobility of both films increased monotonically with the annealing temperature. The concentration of ionized scattering centers decreased significantly in films annealed at 650 °C (independent of their N distributions) owing to the elimination of donor-type defects by annealing. Contrarily, the concentrations of N-induced scattering centers in (1:5) films annealed below 900 °C were similar, while those in (1:3) films annealed above 750 °C decreased significantly, in agreement with the N-atom diffusion behavior of GaAsN layers. Thus, N-distribution homogenization can be related to the reduction of N-induced scattering centers. [ABSTRACT FROM AUTHOR]

• Growth of crystals via the chosen method was successful. • Resultant crystals are euhedral with a platy to blocky morphology. • Optimal growth occurs at temperatures just below the melting point of NiS. • Significant growth was not observed in experiments longer than two weeks. • Impurities in the starting material resulted in the precipitation of minor contaminants. Single crystals of crowningshieldite (α-NiS) were synthesized in three runs via chemical-vapour transport (CVT) over a 20 cm horizontal gradient of 700 → 600 °C (No. 1) and 800 → 700 °C (No. 2 & 3) in evacuated fused silica capsules using natural millerite from Coleman mine in Sudbury, Ontario, Canada with the composition (Ni 0.976 Fe 0.013 Co 0.003) Σ0.992 S and I 2 as a transport reagent. Products were characterized via PXRD and SEM methods. Resultant crystals are euhedral, 10 to 400 μm in diameter, and occur as three distinct populations: 1) platy crystals exhibiting dominant pinacoid { 0001 } and minor dipyramid { 10 1 ¯ 1 }; 2) equant crystals with equal development of both the pinacoid { 0001 } and dipyramid { 10 1 ¯ 1 }; and 3) blocky crystals showing only the dipyramid { 10 1 ¯ 1 }. The largest crystals were produced at higher temperatures, but experiments lasting longer than 12 days did not result in significant additional crystal growth. In addition to euhedral crystals, anhedral droplets were observed to form during run No. 2 & 3 suggesting deposition as a liquid as opposed to solid crystals. Synthesis of crystals from a pure NiS compound as opposed to that of natural composition may improve the quality of the resulting crystals and better constrain the ideal growth temperature. [ABSTRACT FROM AUTHOR]

• LiCl/KCl flux provides phase pure and uniform Fe 1+ δ Se 1- x Te x crystals. • As-grown crystals exhibit bulk superconductivity in contrast to melt-growth method. • Influence of interstitial Fe on its physical properties is studied. An eutectic LiCl/KCl flux method in a horizontal configuration has been used to grow a series of homogeneous Fe 1+ δ Se 1- x Te x single crystals of high quality with 0.5 ≤ x ≤ 1. Compared with previously used melt-growth method, the stable crystallization process in LiCl/KCl flux below their peritectic temperatures results in better homogeneity and crystalline perfection identified by energy dispersive spectrometer and x-ray diffraction. The interstitial Fe value δ remains small within 0.5 ≤ x ≤ 0.85 where the superconducting temperature T C is not sensitive to the Te content with sharp superconducting transition widths Δ T C < 1 K and a maximum of T C = 14.3 K at x = 0.61. The value δ starts to increase quickly accompanied by a deviation of linear behavior of crystal lattice parameters as well as the broadening of Δ T C = 2.1 K at x = 0.91, then suddenly rises up to δ > 0.1 followed by the disappearance of superconductivity and emergence of antiferromagnetic order at x ≥ 0.96. We also observed a metallic to semiconducting transition in the normal state resistivity of Fe 1+ δ Se 1- x Te x with increasing Te content which is related to a localized electronic state induced by the interstitial Fe. The interstitial Fe value δ might be a key physical parameter to understand various properties of Fe 1+ δ Se 1- x Te x system. [ABSTRACT FROM AUTHOR]

• By precisely controlling the growth conditions of α-SrSi 2 , we obtained α −SrSi 2 crystals with large crystal grains and a band gap value of 48 meV, which is larger than previously reported values. As a candidate thermoelectric material operating in the low-temperature regime (room temperature to 473 K), we have examined α-SrSi 2 : a narrow bandgap semiconductor material, which is composed of environmentally benign elements. We are able to report the successful production of single-crystalline-like α-SrSi 2 with clear semiconducting properties by melting synthesis, a thermodynamically stable and thermally equilibrium process that reduces unexpected process contamination and improves crystallinity. The crystals up to 20 × 20 × 5 mm3 have been obtained for a solid–liquid phase reaction temperature of 1308 K for 10 h with a growth rate averaging at 0.617 K/h in the temperature range from 1403 K to 1373 K. The band gap of this material was measured at 48 meV, which is higher than the values previously reported. The power factor was measured at 2.9 mW/mK2 at 300 K, which is the highest value ever reported for undoped α-SrSi 2. Based on the experimental bandgap values, the hybrid functional was used to correct the first-principles calculation method, and the Seebeck coefficient obtained from the first-principles calculation was compared with experimental values. Which values showed good agreement with experimental values. [ABSTRACT FROM AUTHOR]

• Crystals of TlSr 2 Cl 5 and TlSr 2 Br 5 were grown by the Bridgman technique. • The phase diagrams of the systems TlCl – SrCl 2 and TlBr – SrBr 2 were calculated. • TlSr 2 Cl 5 and TlSr 2 Br 5 have the monoclinic crystal structure. • The density of TlSr 2 Cl 5 and TlSr 2 Br 5 is 4.14 g/cm3 and 5.03 g/cm3, respectively. Small diameter (Ø 16 mm) TlSr 2 Cl 5 and TlSr 2 Br 5 crystals were grown by the Vertical Bridgman method. X-ray diffraction measurements show that both have the monoclinic crystal structure with space group P21/c. TlSr 2 Cl 5 and TlSr 2 Br 5 have a density of 4.14 g/cm3 and 5.03 g/cm3, respectively. The effective Z of TlSr 2 Cl 5 and TlSr 2 Br 5 is 63.7 and 58.6, respectively. Radioluminescence spectra of TlSr 2 Cl 5 and TlSr 2 Br 5 feature a broad emission band peaking at 440 and 445 nm, respectively. The light yield of TlSr 2 Cl 5 and TlSr 2 Br 5 was estimated to be 17,000 and 45,000 ph/MeV, respectively. [ABSTRACT FROM AUTHOR]

We report the growth of electrically resistive, high quality vanadium-doped β -Gallium Oxide (β -Ga 2 O 3) single crystals via the optical floating zone growth technique. The characteristic properties of such high resistive V-doped β -Ga 2 O 3 are significantly different compared to the undoped, n -type V-doped and other acceptor-doped crystals. We study the optical absorption in the UV–visible and IR range, temperature-dependent photoluminescence, polarization-dependent Raman spectra and the terahertz transmission properties in the 0.2–2.6 THz range. The V-doped insulating Ga 2 O 3 crystals can be used as an alternative insulating substrate for low leakage devices. Further, the strong anisotropy in terahertz transmission makes it an ideal material for optical applications in the THz region. • Semi-insulating β -Ga 2 O 3 single crystals are grown through Vanadium doping. • High quality — green coloured crystals are obtained with the presence of V3+ ion. • Raman spectroscopic studies show that V3+ substitutes octahedral Ga3+ sites. • These crystals have a bandgap of 4.6 eV and are suitable for terahertz applications. [ABSTRACT FROM AUTHOR]

• Imidazolium glutarate adduct was formed by direct precipitation method. • Single crystal of IMGA was grown by Bridgman technique for the first time. • The grown crystal was crystallized naturally in the (1 0 1) plane. • Etching study reveals the layer-by-layer 2D growth mechanism. • IMGA exhibits a negative photoconductivity nature. In this paper, we have examined the formation of the imidazole glutarate adduct by protonation-deprotonation between imidazole and glutaric acid using a direct precipitation method within a short period. Following that, we have succeeded in growing imidazolium glutarate (IMGA) single crystal directly from synthesized material and we have also grown IMGA single crystal from the melt method using the vertical Bridgman technique for the first time in literature. A special Bridgman furnace was constructed with a slight modification in the winding section for this crystal growth. Crystal structure, phase purity, and growth plane were analyzed for the grown crystal from both single and powder XRD analysis. Functional groups were verified after the growth using FTIR transmittance analysis. The optical homogeneity and growth mechanism were scrutinized by birefringence interferogram and chemical etching studies, respectively. The grown IMGA has 80 % transparency in the entire visible region. The cut-off wavelength of the grown crystal is 235 nm, and the optical band gap energy of IMGA was found to be 5.26 eV. The photocurrent study reveals that IMGA has a negative photoconductivity nature. Third-order nonlinear parameters were found by the Z-scan technique. IMGA has a self-defocusing nature, negative non-linearity, and saturated absorption properties. The calculated χ(3) value is 2.045 x 10-8 esu. [ABSTRACT FROM AUTHOR]

• Green synthesis of MnO x NPs (20 nm) using olive leaf extract as a surfactant. • Mn 2 O 3 exhibits stability within the temperature range [600 °C-900 °C]. • Mn 3 O 4 appears between 300 °C and 600 °C, and reappears at 1000 °C. • MnO x structures show mesoporous characteristics with high surface area. This paper presents the green synthesis of manganese oxide nanoparticles using olive leaf extract (OLE). The extract functions as both a reducing agent, responsible for converting manganese ions into nanoparticles, and a capping agent, aiding in stabilizing the formed nanoparticles. Our focus lies on investigating the thermal stability, phase transformation, and decomposition temperatures of different manganese oxide phases in powder form as a function of the calcination temperature. Since phase transformation depends on temperatures change at the nanoscale both thermogravimetric and differential scanning calorimetry (TGA, DSC) are used to determine the new phase transformation temperatures of the synthesized nanoparticles. Moreover, the phase structure and the exact stoichiometry are studied using ex-situ X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning/transmission electron microscopy (SEM/TEM). XRD and XPS analyses reveal the formation of amorphous MnO x at room temperature (prior to calcination), transitioning to crystalline phases (Mn 2 O 3 and Mn 3 O 4) post-calcination. High-resolution TEM and SEM depict the formation of nanoparticles around 15 nm in size, exhibiting different shapes. BET technique calculations give a very high specific surface area, rending these nanoparticles excellent candidates for several applications. [ABSTRACT FROM AUTHOR]

• Crystal growth of CsMgF 3 by micro-pulling-down method was investigated. • Contrary to published equilibrium phase diagram Cs 4 Mg 3 F 10 was a stable phase. • Due to evaporation, excess CsF was required to grow transparent Cs4Mg3F10 crystals. • Scintillation properties of Cs 4 Mg 3 F 10 were measured. In our search for cross-luminescence (CL) scintillators suitable for fast-timing applications, we have chosen CsMgF 3 as one of the perspective candidates. During the attempts to grow CsMgF 3 by the micro-pulling-down method, we have revealed the presence of Cs 4 Mg 3 F 10 which is in contradiction with the published equilibrium phase diagram. The Cs 4 Mg 3 F 10 has an orthorhombic structure, consisting of face-sharing MgF 6 octahedra triplets (4 triplets per unit cell), joined to 4 other triplets by corner sharing. These chain-like structures are separated by Cs+ ions. Moreover, Cs 4 Mg 3 F 10 is non-hygroscopic despite the hygroscopic nature of CsF. The best crystals were grown from CsF-rich melt to suppress off-stoichiometry due to CsF evaporation during crystal growth. Both radioluminescence spectra and scintillation decay kinetics exhibit complex character and the presence of CL in Cs 4 Mg 3 F 10 is still under question. However, due to relatively low scintillation efficiency and the presence of slow components in scintillation decay, Cs 4 Mg 3 F 10 is not suitable for fast-timing applications. [ABSTRACT FROM AUTHOR]

• BiFeO 3 thin films have been grown directly on Si substrate. • A predeposition process at room temperature and high vacuum conditions is necessary. • The BiFeO 3 thin films grown on bare Si show good ferroelectricity. • The optical band gap presents slight increase with decreasing the film thickness. Multiferroic BiFeO 3 thin films have been widely studied for their intriguing fundamental physics and exotic functional properties. Integration of the BiFeO 3 thin films with semiconductor Si is crucial for the practical development of novel electronic and photosensitive devices. Here, we report the fabrication and physical properties of BiFeO 3 thin films grown directly on bare Si substrate by laser-molecular beam epitaxy. It was found that a predeposition process performed at room temperature and high vacuum conditions is effective and necessary for obtaining the pure-phase BiFeO 3 thin films. X-ray diffraction measurements indicate that the obtained BiFeO 3 thin films are in a single-phase polycrystalline state and show improved crystallinity with increasing thickness, and a transmission electronic microscopy image illustrates an interface layer around 3 nm in thickness existing between the BiFeO 3 thin films and Si substrate. Electrical measurements show that the BiFeO 3 thin films have good ferroelectricity and low leakage current. Moreover, optical properties investigated by spectroscopic ellipsometry demonstrate that the direct band gap of the thin films increases with decreasing thickness. [ABSTRACT FROM AUTHOR]

• MBE growth of Cd 1−x Mn x Te films on Si (1 1 1) substrate. • AFM for the surface morphology and roughness. • XRD and PL spectra to estimate the Mn concentrations. • Room temperature Raman spectra to obtain the vibrational modes. Semiconductors structures with high quality and low cost have been developed and applied in industry on a large scale. The knowledge of basic properties of semiconductor materials growth is important for many technological applications. Cd 1-x Mn x Te films have been used successfully in optoelectronic, solar cells and high energy detectors applications. However, despite the high potential for application of these films, fundamental growth studies on Si(1 1 1) substrate are not extensively explored. In this study, two Cd 1−x Mn x Te (CMT) films (with different Mn concentrations) were successfully prepared on Si(1 1 1) substrate employing molecular beam epitaxy. The morphology and surface roughness of the films were investigated using atomic force microscopy (AFM). X-ray diffraction was used to investigate the structural quality and to determine the Mn concentration of the samples. It shows that the films have only (1 1 1) orientation despite a lattice mismatch of almost 19%. Room temperature micro-photoluminescence (µ-PL) spectra shows a high intensity band edge emission and very low intensity defect related emission. Raman spectroscopy of the samples was carried out in order to obtain the vibrational modes. First, second and third order CdTe-like and MnTe-like longitudinal-optical (LO) phonon modes were observed. These results demonstrate the potential of these structures for room temperature applications. [ABSTRACT FROM AUTHOR]

• HD method can obtain more crystallization hits of "several diffraction spots". • HD method was beneficial for the quality of protein crystals. • HD method in CDM plate possess larger number of screening crystallization hits than that of T plate. Obtaining good quality protein crystals is still desirable for high resolution structural determination of the proteins using crystallography. The crystal quality is affected by the growth environment and growth methods. As frequently used methods in practical protein crystallization, sitting and hanging-drop methods are seldom compared in terms of crystal quality in the literatures. We performed a systematic comparison on the quality of the protein crystals grown in sitting and hanging-drop methods using different crystallization plates: cross-diffusion microbatch plate (CDM SD: CDM plate, sitting drop method; CDM HD: CDM plate, hanging drop method), traditional sitting and hanging-drop vapor diffusion plates (T SD: traditional plate, sitting drop method; and T HD: traditional plate, hanging drop method). Five different proteins, proteinase K (prk), lysozyme (lys), concanavalin A VI (con), catalase (cat) and α-Chymotrypsinogen A II (chy), were used. The crystal quality was compared in terms of the resolution limit, mosaicity and Wilson plot B factor. It was found that the crystals grown in CDM plate using the hanging drop method (CDM HD) exhibited the best morphology and the best crystal quality. X-ray diffraction tests showed that the CDM plate using hanging drop method is indeed a practical and useful method for obtaining high-quality protein crystals. [ABSTRACT FROM AUTHOR]

• MgC 1- x Ni 3- y crystals were successfully grown under high pressure conditions. • Bulk single crystals with dimensions up to ∼ (1–1.2) × (0.8–1.0) × (0.4–0.6) mm3. • Due to C and Ni deficiencies a critical temperature (T c) ranges between 6.3 and 6.8 K. By varying the parameters controlling the growth of crystals, including the thermodynamic variables, such as temperature, pressure, and reagent composition and the kinetic factors, namely reaction time and cooling rate, we found the most appropriate conditions for the reproducible growth of the nonstoichiometric antiperovskite superconductors MgC 1- x Ni 3- y. Bulk single crystals of MgC 1- x Ni 3- y were grown by a self-flux method at 3 GPa and 1700 °C using a mixture of Mg, C, and Ni powders in a molar ratio 1:1.25:3. The as-grown black colored crystals, mechanically extracted from solidified lump, exhibit various irregular three dimensional shapes, with flat surfaces and maximum dimensions up to ∼ (1–1.2) × (0.8–1.0) × (0.4–0.6) mm3. Single-crystal X-ray diffraction refinement confirmed the high structural perfection of the grown crystals [Space group Pm -3 m , No 221, Z = 1, a = 3.7913(1) Å, and V = 54.5(1) Å3], but also the presence of deficiencies on the C and Ni sites. Temperature-dependent magnetization measurements showed a single-phase behaviour with a critical temperature (T c) ranging between 6.3 and 6.8 K due to the slightly different C and Ni stoichiometries of MgC 1- x Ni 3- y crystals. The growth of relatively large crystals reported here could provide a helpful guidance for further syntheses of various 3 d -based antiperovskite intermetallics under high pressure. [ABSTRACT FROM AUTHOR]

• Crystallization behavior of hydrohalite is poorly known. • A simple and fast procedure of hydrohalite crystallization is reported. • From X-ray diffraction studies its thermal expansion is reported for the first time. The existing literature on the phase diagram of NaCl-H 2 O system and the study of crystallization of sodium chloride dihydrate NaCl·2H 2 O (mineral name hydrohalite) is briefly reviewed first. Then a simple and fast procedure for NaCl·2H 2 O crystallization is described to obtain large enough (∼1 cm long) single crystals in amount of hundreds grams in one batch. This procedure can stimulate the investigation of physico-chemical properties of hydrohalite. The characterization of the crystallized samples with X-ray (single-crystal and powder) diffraction did allow estimating the average volume thermal expansion of hydrohalite as of ∼70∙10–6 K−1 over temperature range from 100 to 250 K. [ABSTRACT FROM AUTHOR]

• Synthetic conditions for obtaining a vaterite single phase by liquid phase reaction were clarified. • Amorphous calcium carbonate (ACC) was formed promptly after the reaction. • The pH during crystallization of ACC was involved in the formation of vaterite. • When the pH was 9.7 or less, a single phase of vaterite was obtained. • At the pH of 9.7, the abundance ratio of HCO 3 − ion was 80% or more. This paper reports on the effect of pH on polymorphism of calcium carbonate (vaterite) formed in the CaCl 2 -Na 2 CO 3 -H 2 O reaction system. The initial pH of CaCl 2 aqueous solution was adjusted to the initial pH 2.0–11.3 using HCl and NH 3 aqueous solution. The initial pH was 6.5 without pH adjustment. When the reaction was carried out, amorphous calcium carbonate (ACC) was formed at the early stage of the reaction and crystallized to calcite and vatrite after 3 min of stirring. Formation ratio of vaterite at this time was 60％. Single-phase vaterite was formed at initial pH 2.0–2.5. Further, focusing on the pH during ACC crystallization. When HCO 3 − ions were 80% or more during ACC crystallization, single-phase vaterite was formed. [ABSTRACT FROM AUTHOR]

Highlights • High quality ZnTe layers were prepared on the sapphire substrates. • S-, c-, a-, and r- sapphire showed step terrace structure after the annealing. • Nanofacet structure was observed from the m- sapphire surface after the annealing. • Those structures were very effective to improve the crystal quality of ZnTe layers. • ZnTe layers on sapphire were doped using nitrogen. High p-type doping was confirmed. Abstract ZnTe layers were grown on various orientation surfaces of sapphire substrates, namely c-, a-, r-, and S-planes. Single domain dominant layers were achieved by carefully controlling the substrate orientation and introducing the thin buffer layer. The substrate surfaces were annealed at approximately 1000 °C to achieve an atomically smooth surface with step-terrace structures. Single domain layers were achieved by employing the step-terrace structured substrates. A nanofacet structure of the substrate surface consisting of the r-plane and the S-plane was obtained by annealing the m-plane substrate surface. Nucleation of ZnTe occurred along the nanofacet. It was confirmed that preferential nucleation of ZnTe on the S-plane of the nanofacet took place. Nitrogen doping of the ZnTe layer was performed, with the doping efficiency confirmed as being as good as ZnTe layers prepared on GaAs substrates. This is another indication of the high crystal quality for the prepared ZnTe layer. [ABSTRACT FROM AUTHOR]

Highlights • Holmium and Erbium doped KTiOPO 4 crystals were grown by a top-seeded solution growth method. • Transparent KTP:Ho and KTP:Er crystal were obtained from the mixed K 6 P 4 O 13 solvent containing MoO 3. • The doping of Ho and Er into KTP can alters the TiO 6 network in the crystal. • The structural analysis of Ho and Er:KTP crystals were analyzed using Raman Shift and Electron Spin Resonance (ESR) Spectrum. • The characteristic SHG emission was analyzed. Abstract KTiOPO 4 :Ho and KTiOPO 4 :Er single crystals are grown by a top-seeded solution growth method from potassium phosphate and MoO 3 flux. The crystalline phase, packing structure and chemical composition of the crystals are analyzed by X-ray diffraction (XRD), energy dispersive spectrum (EDS). The doping of Ho and Er induced strain in the crystal is determined from Williamson–Hall relation. The bonding between titanium and oxygen of Ho and Er doping in the KTP crystal is changing the pseudo-symmetrical deviation in the lattice. The bonding of O and Ti decreases with doping Ho and Er and Ti3+ content in the crystal. The bonding, distortion of the TiO 6 -TiO 6 chain and change in inter-atomic distances by erbium and holmium doping are assessed by Raman spectroscopy and low temperature ESR spectroscopy which evidences the low concentration of Ti3+ presence in the crystal. The KTiOPO 4 :Ho and KTiOPO 4 :Er single crystal shows second harmonic generation properties which shows that the efficiency ratio of ηKTiOPO 4 :Ho/η KTiOPO 4 = 0.63 and ηKTiOPO 4 :Er/η KTiOPO 4 = 0.80. [ABSTRACT FROM AUTHOR]

Highlights • An organic diphenylmethanol single crystal was grown by vertical Bridgman technique. • The band gap value of the grown crystal is estimated as 4.43 eV. • The third order NLO parameters n 2 , β and χ3 values were evaluated by Z-scan studies. • The laser damage threshold of the crystal is found to be 15.2 GW/cm2. Abstract An organic nonlinear optical diphenylmethanol single crystal was grown by vertical Bridgman technique using single wall ampoule. The lattice parameters and crystal system of grown crystal were confirmed by single crystal XRD analysis. The functional groups present in the crystal were identified by FTIR analysis. The thermal properties of the grown crystal were studied by thermo-gravimetric and differential thermal analyses. UV–vis-NIR spectroscopic analysis shows that the crystal has low cut-off wavelength at 271 nm and band gap value of 4.43 eV. The fluorescence spectrum indicates that the crystal exhibits emission at 289 nm wavelength in UV region. The second harmonic generation efficiency of diphenylmethanol was determined by Kurtz and Perry powder technique. The third order nonlinear optical parameters like nonlinear refractive index (n 2), nonlinear absorption coefficient (β) and third order nonlinear susceptibility (χ 3) of the crystal were determined by Z-scan technique using cw Nd:YAG laser light of wavelength 532 nm. The self-defocusing and saturation absorption nature of the crystal were identified from Z-scan closed and open aperture methods respectively. The crystal exhibits good power limiting behaviour due to non linear refraction. The laser damage threshold study indicates that the crystal has no surface damage upto 29.5 mJ. [ABSTRACT FROM AUTHOR]

Highlights • Curvature-controllable and crack-free AlN template realized. • Double-sided sputtering and high-temperature annealing employed to achieve this. • Twist component of X-ray rocking curve markedly improved after annealing. • Experimental and calculated curvature and in-plane stress agreed well. Abstract Post-growth high-temperature annealing of sputtered AlN films is a promising approach to realize high-quality AlN templates for deep-ultraviolet light-emitting diode applications. This paper proposes the double-sided sputtering of AlN on double-sided polished sapphire to suppress the wafer bowing caused by high-temperature annealing. Similar to the case of single-sided sputtering, the twist component of the X-ray rocking curve was markedly improved after annealing, yielding rocking curve widths of 256–321 arcsec in (10–12). By varying the backside thickness, the curvature was controlled from −27 km−1 to 29 km−1, while a crack-free surface was maintained on the front side of AlN. The experimentally obtained curvature and in-plane stress agreed well with the calculation based on thermal stress analysis in the multilayer system. [ABSTRACT FROM AUTHOR]

Highlights • Strain-relaxation of annealed sputtered AlN film on c -plane sapphire was revealed. • Sputtered AlN films before annealing have different strains and tilt mosaics. • The AlN film after annealing consists of a layer that have a compressive strain. • After MOVPE growth, the compressive strain was inherited. Abstract The strain relaxation of sputter-deposited AlN (sp-AlN) films on c -plane sapphire substrates before and after face-to-face annealing (FFA) was evaluated. After FFA, the AlN films consisted of a layer with compressive strain and an extremely low dislocation density, which was ascribed to solid-state growth during FFA. In addition, the crystallinity was further improved after the homoepitaxial growth of AlN by metal-organic vapor phase expitaxy (MOVPE). The full widths at half maximum of the X-ray rocking curves of AlN (0 0 0 2) and (1 0 −1 2) for the MOVPE-grown AlN layer on the FFA-sp-AlN film were 15 and 240 arcsec, respectively. The surface morphology of the MOVPE-grown AlN layer on the FFA-sp-AlN film was covered with an atomically flat step-and-terrace structure. The compressive strain of the MOVPE-grown AlN layer was inherited from the underlying FFA-sp-AlN film. [ABSTRACT FROM AUTHOR]

Highlights • Systematical investigation of the crystal growth of BiSb thin films on GaAs(1 1 1)A, GaAs(1 1 1)B, and GaAs(0 0 1) substrates. • Non-trivial growth mode of BiSb. • Growth depends not only on the crystal orientation but also on the surface termination of GaAs. • Hints for future integration of BiSb thin films to realistic spin devices. Abstract We investigate the crystal growth of BiSb thin films on various GaAs substrates with different crystal orientation and surface termination. We found the non-trivial growth mode of BiSb which depends on the crystal orientation/surface termination of GaAs. While BiSb(0 0 1) can be grown epitaxially on GaAs(1 1 1)A, only textured BiSb(0 1 2) can be grown on GaAs(1 1 1)B even with the help of an ultrathin Bi buffer layer, indicating the critical role of surface termination of the GaAs(1 1 1) substrates. Meanwhile, only textured BiSb(0 0 1) thin films grow on GaAs(0 0 1) instead of BiSb(0 1 2), indicating that symmetry matching plays a little role on the growth of BiSb on GaAs(0 0 1). [ABSTRACT FROM AUTHOR]

Highlights • AlN films were fabricated on SiC substrates by sputtering deposition. • High temperature annealing improved crystalline quality of the AlN films. • Strain relaxation in AlN films occurred during high temperature annealing. • Homoepitaxially grown AlN films on the template exhibited an atomically flat surface. Abstract High-quality AlN templates fabricated by sputtering-deposition and post-deposition high-temperature annealing have great potential for deep ultraviolet light-emitting device applications. In this work, we fabricated AlN films on 6H-SiC substrates by sputtering and face-to-face annealing and characterized the structural quality of the AlN films before and after annealing. As reported in previous studies, to accomplish high-quality AlN films on SiC substrates using conventional methods, such as molecular beam epitaxy or metalorganic vapor phase epitaxy (MOVPE), it is important to grow the AlN on the SiC coherently. However, in this work, although the annealed AlN films were fully relaxed from the SiC substrates, or even had tensile strain, the AlN films indicated high crystallinity. The X-ray rocking curve full width at half maximum (XRC-FWHM) values of the 200-nm-thick annealed AlN film were 17 and 246 arcsec for the AlN (0002) and (10–12) diffraction, respectively. Though the annealed AlN film indicated rough surfaces with bunched step structures, the surface morphology was remarkably improved by MOVPE growth and clear atomic step-and-terrace structures were formed. The XRC-FWHM values of the MOVPE-grown AlN were 90 and 239 arcsec for the AlN (0002) and (10–12) diffraction, respectively. [ABSTRACT FROM AUTHOR]

Highlights • Growth of γ-glycine from silver sulphate is reported for the first time. • Grown γ-glycine highly transparent in entire visible region. • SHG efficiency of 0.1 M AgSO 4 added glycine crystal is 1.67 times that of KDP. • The grown crystal exhibits a positive photoconductivity. • Hence, title compound is suitable for photonics and optoelectronic applications. Abstract In the present work 0.1–0.5 M proportions of silver sulphate (AgSO 4) added glycine single crystals were grown by slow solvent evaporation method. The Powder XRD study confirms that the grown crystals have γ-glycine crystal structure and it crystallizes into a hexagonal structure with a non-centrosymmetric space group of P3 1. The dielectric constant and dielectric loss of grown crystal was carried out as a function of frequency and the results were discussed. The positive photoconducting nature of the grown crystals was studied by the photoconductivity study. Second harmonic generation (SHG) efficiency of the grown γ-glycine crystal was assessed by using Nd: YAG laser. The results confirms that the grown crystals have higher efficiency compared to the reference (KDP) crystal. [ABSTRACT FROM AUTHOR]

• The unique quaternary (Sb 0.2 Sn 0.8) 0.5 (S 0.9 Se 0.1) 0.5 single crystals were grown using the direct vapour transport method. • Investigation into the effect of Sb and Se doping on optoelectronic properties of SnS crystals. • (Sb 0.2 Sn 0.8) 0.5 (S 0.9 Se 0.1) 0.5 based photodetector offers strong self-powered photoresponse and rapid response times. • Results extensively favour (Sb 0.2 Sn 0.8) 0.5 (S 0.9 Se 0.1) 0.5 crystals for switching and optoelectronic devices. The need to develop electronic systems capable of functioning without an external power source is an utmost priority, especially in the pursuit of self-powered photodetection. Through the direct vapor transport (DVT) method, we have synthesized a single crystal of the quaternary compound (Sb 0.2 Sn 0.8) 0.5 (S 0.9 Se 0.1) 0.5 for self-driven photodetectors. The crystal's elemental composition was ascertained via energy-dispersive X-ray analysis (EDX), along with Field emission scanning electron microscopy (FESEM) provided insight into its surface morphology. The orthorhombic crystal system of the grown sample has been validated by a powder X-ray diffractometer (XRD). The regular spot pattern of SAED and the well-defined sharp peaks observed in the XRD graph collectively indicate the crystal's pronounced crystalline quality. The lattice parameters closely resemble the reported data. A UV–VIS-NIR spectrometer was utilized to deduce a direct optical band gap of 1.49 eV. Raman spectroscopy was used to examine different phonon modes. We analyzed its pulsed photo response by subjecting the grown crystal to different wavelengths and varying intensities of white light at self-biased mode and by applying 1 V bias. Our analysis enabled us to determine favourable photodetection parameters. [ABSTRACT FROM AUTHOR]

[Display omitted] • We investigated the effects of NH 4 NO 3 salts on the growth of norsethite. • The solubility of norsethite increases ∼35 times by adding NH 4 NO 3. • The solubility of witherite also increases ∼45 times by adding NH 4 NO 3. • We succeeded in growing 170 μm-sized norsethite only in one month. • The addition of NH 4 NO 3 is promising for the growth of large norsethite. Crystallization of norsethite [BaMg(CO 3) 2 ] receives considerable attention as a key for solving geological problems, and environmental and resource issues. Noresthite is poorly soluble in water, and is synthesized via witherite [BaCO 3 ] by solution-mediated transformation. In contrast, owing to the difficulties such as tremendous growth time and consideration of multi-step reactions, the shape and size of norsethite were not satisfactory for further investigations so far. Here we tried to increase the solubility of the crystals to overcome these difficulties of the growth by adding NH 4 NO 3. The solubilities of norsethite and witherite in the presence of NH 4 NO 3 were ∼35 and ∼45 times higher than those in the absence of NH 4 NO 3 , respectively. At 90 °C, the growth rate of norsethite in NH 4 NO 3 solutions was ∼17 times higher than that in NH 4 NO 3 -free solutions, and norsethite in NH 4 NO 3 solutions nucleated immediately after mixing the raw materials. Finally, we succeeded in synthesizing bulky norsethite crystals of 170 μm size only in one month, utilizing 0.1–1 M NH 4 NO 3 solutions of 90 °C. We could explain the appearance of large norsethite, considering that norsethite dominantly consumes the solute by adding NH 4 NO 3 compared with witherite. The findings provide a breakthrough in the growth technique of double carbonates. [ABSTRACT FROM AUTHOR]

Abstract Dimethylamino pyridinium p-bromo-chlorophenolate crystals were grown by slow evaporation solution growth technique. Single crystal X-ray diffraction studies divulge that the composite belongs to monoclinic system with centrosymmetric space group P 2 (1)/c. The unit cell parameters are a = 9.72 Å, b = 12.95 Å, c = 11.63 Å. The functional groups present in the compound were identified using FT-IR and FT-Raman studies. Thermal studies were carried out using thermogravimetric analysis and differential scanning calorimetry confirms the material decomposes beyond 139 °C. Microhardness stability analysed by Vickers hardness test has confirm the material to be a soft material with n value 2.26. Dielectric properties were assessed by impedance analysis from 40 °C to 90 °C. Higher transmission possessed by the crystal in the visible region supports the suitability of the crystal for higher harmonic generation. Highlights • Structural determination by single crystal X-ray diffraction studies exhibits monoclinic crystal system. • Dimethylamino pyridinium p-bromo–chlorophenolate crystal belongs to the soft material category. • The mixed crystal has a good thermal stability and it does not undergo any phase transition. [ABSTRACT FROM AUTHOR]

Highlights • Reaction order is close to 1 with regards to CH 3 CN. • Reaction order is close to 0 with regards to TiCl 4. • Coating composition unaffected by precursor partial pressure. • Texture forming mechanism for 〈2 1 1〉 growth. Abstract The growth mechanism of Ti(C,N) coatings produced by chemical vapor deposition was investigated as a function of the TiCl 4 /CH 3 CN molar ratio in excess of H 2. The depositions were carried out at a total pressure of 8 kPa, using single crystalline (0 0 l) α-Al 2 O 3 substrates. The Ti(C,N) coatings were characterized by X–ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy. The investigated coatings were between 6 and 13 µm thick. The reaction orders of TiCl 4 and CH 3 CN were determined to 0 and 1, respectively, showing that CH 3 CN is the rate-determining reactant. The preferred orientation of the deposited Ti(C,N) was investigated, showing that molar ratios TiCl 4 /CH 3 CN higher than 2.5 lead to 〈2 1 1〉/〈3 1 1〉 oriented coatings. A formation mechanism for the 〈2 1 1〉/〈3 1 1〉 orientation s is suggested. Such high ratios lead to the formation of Ti {1 1 1} twinning planes, which provide surface sites that can facilitate fast dissociation of the strong cyanide bond, and thereby cause faster growth in the 〈2 1 1〉/〈3 1 1〉 directions. Coatings deposited at lower molar ratios show a pronounced 〈1 1 1〉 out-of-plane orientation, characterized by a {1 1 1} rocking curve yielding values for full width at half maximum (FWHM) below 0.5°. [ABSTRACT FROM AUTHOR]

Highlights • Pure, In and Sb doped SnS 2 single crystals grown by DVT technique. • The single crystals were stoichiometric and of single phase possessing hexagonal crystal structure. • The single crystals possessed direct optical bandgap. • Optical microscopy showed layer growth mechanism. Abstract Pure SnS 2 , 5% In-doped SnS 2 , 15% In-doped SnS 2 , 5% Sb-doped SnS 2 and 15% Sb-doped SnS 2 single crystals are grown in closed sealed quartz ampoule by direct vapour transport technique. The energy dispersive analysis of X-rays analysis of all the five as-grown single crystals showed them to be stoichiometric. The X-ray diffraction analysis showed that all the crystals are single phase possessing a hexagonal structure with (0 0 1) preferential orientation. The surface morphology of as-grown single crystals studied by scanning electron microscopy and optical microscopy showed crystal growth is by layer growth mechanism supported by screw dislocation. Selected area electron diffraction showed hexagonal spot pattern confirming the single crystalline nature of the crystals. Optical bandgap of the as-grown crystals determined by UV–Vis-NIR spectroscopy showed that the single crystals possess direct optical bandgap and the value varied between 1.89 and 2.31 eV. The photoluminescence spectra study showed the presence of six peaks. The Raman spectra showed SnS 2 type the A 1g vibrational mode and shifting in A 1g vibrational mode with In and Sb doping. The results are elaborated in details. [ABSTRACT FROM AUTHOR]

Highlights • Growth of l -alanine potassium nitrate (LAPN) is reported for the first time. • Grown LAPN highly transparent in visible and NIR region. • SHG efficiency of grown LLAPN crystal is 1.25 times that of reference KDP. • The grown crystal exhibits a positive photoconductivity. • Hence, title compound is suitable for photonics and optoelectronic applications. Abstract In this present work, we have successfully grown L -Alanine Potassium Nitrate (LAPN) single crystals from aqueous solution by spontaneous nucleation solution growth method. The crystal structure and lattice parameters of the unit cell of the grown LAPN single crystals have been determined using single crystal X-ray diffraction (SXRD) and powder X-ray diffraction (PXRD) techniques. The functional groups present in the grown crystals have been confirmed by means of Fourier Transform Infrared (FT-IR) analysis. Elemental analysis CHN was performed to confirm the inclusion of potassium nitrate into the crystal lattice of L -Alanine. The UV-Vis-NIR study has been carried out within 200–2500 nm to determine the optical transparency and the dielectric nature of the grown LAPN single crystal. Second Harmonic Generation (SHG) efficiency of the grown crystalline powdered sample was studied by Kurtz-Perry powder technique using a Nd: YAG laser, revealed increased SHG efficiency with the highest of about 1.25 times in the presence of potassium nitrate compared to the standard potassium dihydrogen orthophosphate (KDP). The dielectric constant and dielectric loss of LAPN crystal was carried out as a function of frequency and the obtained results were discussed. The photoconductivity nature of the grown crystal was confirmed from photoconductivity analysis. [ABSTRACT FROM AUTHOR]

Highlights • The PL intensity from β-FeSi 2 was enhanced by pre-coating silver on Si substrates. • A modified-Si surface due to Ag diffusion was reconstructed into domain structure. • This mechanism decreased the non-radiative recombination centers density in β-FeSi 2. Abstract The improving of the crystal quality and pronounced enhancement of photoluminescence intensity from β-FeSi 2 were achieved by pre-coating silver (Ag) layers on Si(1 0 0) substrates. A modified-Si surface, which formed during the heating step before β-FeSi 2 deposition due to Ag diffusion, was reconstructed the surface into domain structure that minimize the strain caused by lattice matching of β-FeSi 2 and Si. This mechanism led to the formation of β-FeSi 2 film with very low levels of density of non-radiative recombination centers, and led to the pronounced enhancement of PL intensity. [ABSTRACT FROM AUTHOR]

Highlights • Effect of MnSO 4 addition on glycine has been reported for the first time. • Grown γ-glycine is highly transparent in the visible and NIR region. • SHG efficiency of grown γ-glycine crystal is 1.67 times that of reference KDP crystal. • The grown crystal exhibits positive photoconducting nature. • Hence, title compound is suitable for photonics and optoelectronic applications. Abstract In this present work, MnSO 4 -added glycine single crystals were grown by slow solvent evaporation method. Powder XRD study confirms that the crystals grown in γ-phase and it crystallizes in hexagonal structure with a space group of P3 1. Differential Scanning Calorimetry study revealed that the thermal characteristics of the grown polymorph. The dielectric constant and dielectric loss of grown crystal was carried out as a function of frequency and the results were discussed. The positive photoconducting nature of the grown crystals was studied by photoconductivity study. Non-Linear Optical (NLO) productivity of grown γ-glycine crystal was measured by using Nd: YAG laser. It was found to be 1.67 times higher than that of a reference (KDP). [ABSTRACT FROM AUTHOR]

Highlights • l -GluHCL belongs to orthorhombic system. • l -GluHCL highly transparent in visible region. • l -GluHCL crystal with low dielectric loss expose low defect density. • SHG efficiency of grown crystal is 0.15 times that of standard inorganic KDP. Abstract A single crystal of l -glutamic acid hydrochloride was successfully grown by slow evaporation method. The grown crystal was analyzed for structural, optical and thermal studies. The powder XRD studies were applied to analyze the lattice parameter of the grown crystals. The optical band gap of the grown crystal was effectuate by UV–Vis spectroscopy. The thermal strength of the grown crystals was observed by Differential Scanning Calorimetry studies. The dielectric study carried out determined the dielectric constant and dielectric loss decreases with a higher frequency at various temperatures. The photoconductivity study contributed its positive photo conducting nature. The second harmonic generation (SHG) for the grown crystal was confirmed by Nd: YAG laser Kurtz Perry technique and the efficiency of the grown crystal was evaluated with KDP crystal. [ABSTRACT FROM AUTHOR]

Highlights • High quality crystal of Nd3+doped CLTGG was successfully grown by the Czochralski method. • Complete emission and absorption spectral parameters were calculated by J-O theory. • High performance thermal properties of Nd:CLTGG crystal were presented. • CW laser output at wavelength of 1.06 um were shown for the first time. Abstract A large single crystal of Nd3+-doped calcium lithium tantalum gallium garnet (CLTGG) was successfully grown by Czochralski method. The effective distribution coefficient of Nd3+ was measured as 2.01. A series of thermal properties was systematically tested, and the Nd:CLTGG crystals exhibited superior thermal properties over those of Nd:CLNGG crystals. The emission and absorption spectra were obtained at room temperature. The FWHM (Full Width Half Maximum) of the absorption peak at 808 nm was 18 nm, and the emission peak at 1060 nm was 20 nm. The fluorescence lifetime, absorption coefficient, and other spectral parameters were calculated by J-O theory. In addition, the CW laser performance at a wavelength of 1.06 um was measured at room temperature. The slope and light conversion efficiencies were 17.8% and 16.3%, and the maximum output power was 1.32 W. These results revealed that Nd:CLTGG is promising high-performance laser crystal. [ABSTRACT FROM AUTHOR]

Highlights • Metastable crystal of acetaminophen grew via solution-mediated phase transformation. • Crystal defects were reduced by using supersaturation control and new seeding process. • High temporal stability of metastable phase was achieved by improvement of its quality. Abstract We improved the crystal quality of the metastable phase of a pharmaceutical compound acetaminophen (form II) using solution-mediated phase transformation (SMPT) combined with the control of supersaturation and crystal size. Form II crystals grew at low supersaturation via SMPT of the trihydrate at low temperature (10 °C). While crystal growth rate was low compared to the 20 °C condition, crystals had many defects such as solution inclusions or cracks at 20 °C, but few at 10 °C. The ratio of form II crystals with any defects was small (12%), about 1/3 that of the 20 °C condition. Since the concentration gradient on the crystal surface was relatively small at low bulk supersaturation, high-quality crystals grew uniformly. However, large crystals (>∼0.8 mm) were still defective even at low supersaturation, because concentration gradient is large on large surfaces. Using a new seed-dipping process, obtained crystals were small and uniform in size (∼0.4 mm), and the ratio of defective crystals was reduced to 6%. Powder X-ray diffraction analysis revealed that form II crystals were ∼6 times more temporally stable than in the 20 °C condition. We found that high-quality crystals of metastable phase with high temporal stability could be realized by low supersaturation and reduction of the crystal size via SMPT. [ABSTRACT FROM AUTHOR]

Highlights • Optimal MOCVD growth parameters for InAs/GaSb superlattices were determined. • Sharp X-ray diffraction peaks and clear photoluminescence were observed. • Step-flow growth mode was achieved in InAs/GaSb superlattice growth. • GaAs/GaSb superlattices with low lattice mismatch were realized via As-Sb exchange. Abstract The effect of growth parameters in metalorganic chemical vapor deposition (MOCVD) on the crystal quality and surface morphology of the InAs/GaSb superlattices (SLs) on InAs substrates was systematically investigated by X-ray diffraction, scanning transmission electron microscopy, atomic force microscopy and photoluminescence. It was found that InAs/GaSb SLs grown at 530 °C with intentionally-formed GaAs-type interfaces exhibited lattice mismatch as low as −0.01%, abrupt SL interfaces and atomically smooth surface with a root mean square roughness of only 0.136 nm. Clear photoluminescence was observed around 8 μm at 77 K for a long-wavelength SL structure. The nominal thickness of the GaAs-type interfacial layers and the overall SL strain can be effectively controlled by tuning the AsH 3 flow rate. In addition, high-quality GaAs/GaSb SLs on InAs substrate were demonstrated as a replacement of the GaAsSb alloys. An AsH 3 -purge step was introduced after GaSb growth to form GaAs layers via As-Sb exchange. An optimal condition has resulted in lattice-mismatch of 0.21% and surface roughness of 0.122 nm for the GaAs/GaSb SLs. [ABSTRACT FROM AUTHOR]

Highlights • Growth of l- glutamic acid polymorphs from (NH 4) 2 SO 4 is reported for the first time. • Crystal shows highly transparent in visible and NIR region. • SHG efficiency of α l -glutamic acid crystal is 0.7 times that of KDP. • Growth of α- l -glutamic acid exhibits a positive photoconductivity. • Hence, title compound is suitable for photonics and optoelectronic applications. Abstract In this work, l -glutamic acid polymorphs of β and α crystal were grown by the slow evaporation method by using additives of ammonium sulphate. The selective additive ammonium sulphate was added at different concentrations to study the l -glutamic acid polymorphs. It creates that at a level of 0.04 g/100 ml, the additive contributed to the crystallization of l -glutamic acid in α-form, and this additive exhibited an inhibitory action on the transition of α crystal to β crystals. The lower concentration of ammonium sulphate provides β polymorph whereas the higher concentration of ammonium sulphate provides α polymorph crystal. Structural confirmation of the grown polymorph was executed by powder X-ray diffraction study. UV–Vis-NIR spectral analysis the optical transparency of grown crystals. The powder second harmonic conversion efficiency of grown crystal was determined by using Kurtz and Perry powder technique and the efficiency compared to standard inorganic material potassium dihydrogen phosphate. The dielectric properties of dielectric constant and dielectric loss of grown crystal have been measured as a function of frequency and temperature. The photoconductivity study contributed its positive photo conducting nature. In vitro antimicrobial activity of grown crystals was analyzed against gram positive and negative bacteria's carried out by disk diffusion process and created that the crystal proves superior inhibition against various bacteria's strains. [ABSTRACT FROM AUTHOR]

Highlights • 2 in. GaN crystals and wafers were produced by ammonothermal method. • X-ray characterization method suggested to check surface and subsurface damage. • (1 1 4) X-ray rocking curves measurements for each step of back-end processing. • Lack of uniformity of surface damage from different companies and from sample to sample. Abstract SixPoint Materials has successfully switched to production of two-inch diameter GaN wafers using the ammonothermal method. Crystal quality values are high with dislocation densities typically in the low 105 cm−2. In efforts to produce true epi-ready material, investigations were made to develop a technique to study surface damage caused by the back-end process using X-ray diffraction methods. Analysis of peak tailing from X-ray rocking curves of the (1 1 4) reflection indicates the progression of surface damage during each step of the back-end process. For instance, the tailing can be partially represented using full width five thousand max (FW5000M) values. By using a peak with a low glancing angle, such as the (1 1 4) reflection's angle of 10.8662°, more of the X-ray beam is scattered in the surface region, providing an improved measurement of surface damage. Since this technique is non-destructive and can be performed without dismounting the sample from its ceramic back-end processing plate, it can provide information on the damaged layer at each stage of the back-end process. Using this technique to evaluate samples from various manufacturers, we found a lack of uniformity in surface damage from GaN companies. It is our hope that this technique will be adopted to better standardize surface damage measurements in the GaN field. [ABSTRACT FROM AUTHOR]

Highlights • GaNAs layers are grown with and without hydrogen by chemical beam epitaxy. • Both XRD and AFM results show that hydrogen improves the quality of GaNAs layer. • Hydrogen induced two-dimensional growth mode is responsible for the improvement. • This conclusion is also supported by XRD and PL results for InGaNAs/GaAs SQWs. Abstract In order to investigate the impact of hydrogen on the quality of GaNAs, GaNAs layers are grown by chemical beam epitaxy (CBE) with and without hydrogen. X-ray diffraction (XRD) results show that hydrogen improves nitrogen incorporation significantly for GaNAs. For GaNAs layer grown without hydrogen, nitrogen incorporation cannot be detected, whereas for GaNAs layer grown with hydrogen, nitrogen incorporation can be clearly detected by XRD. Atomic force microscopy (AFM) observations show that root mean square (RMS) roughness for GaNAs layer grown without hydrogen is around 34 times higher than that grown with hydrogen. High quality GaNAs layer with RMS roughness of around 1 monolayer is successfully obtained with hydrogen. Based upon XRD and AFM results, it is suggested that atomic hydrogen induced enhancement of two-dimensional growth mode is responsible for the quality improvement. This conclusion is also supported by XRD and photoluminescence (PL) results for InGaNAs/GaAs SQWs grown with and without hydrogen. [ABSTRACT FROM AUTHOR]

Highlights • Thick freestanding HVPE-GaN with very low dislocation density. • Biaxial stress free substrate for homoepitaxy growth. • Probing uniform areal and volumetric distribution of pervasive impurities. • Identification of intrinsic pervasive donor and acceptor impurities. • High free carrier mobility. Abstract We investigated the structural, optical, and electrical properties of thick freestanding HVPE GaN films deposited on and then removed from substrates consisting of thick HVPE-GaN deposited on ammonothemal-substrates. High-resolution XR diffraction of both Ga- and N-polar faces and XR topography studies confirmed high crystalline quality. Raman scattering measurements carried on both polar faces of these samples confirm that they are free of biaxial stress, and also confirm that the Si concentration increases with growth, as verified by SIMS analysis. This variation in the incorporation of the Si shallow impurity was also observed in the photoluminescence of these samples. Electrical transport measurements are consistent with good electrical properties. The results strongly suggest that this type of substrate could be conveniently tailored for the fabrication of high performance devices. [ABSTRACT FROM AUTHOR]

Highlights • Efficient doping demands low concentration of pervasive background impurities. • Efficient doping compensation requires elimination of any additional impurity. • Fe-doping has been achieved without the introduction of carbon impurities. • Reduced concentration of Fe avoid the formation of metal precipitates. • The crystalline quality of the GaN layers have been preserved. Abstract Thick freestanding iron-doped semi-insulating GaN layers were grown by Hydride Vapor Phase Epitaxy on GaN/sapphire templates. Iron doping was achieved by using Fe57-enriched Fe 2 O 3 reduced to elemental Fe in-situ avoiding uptake of C from organometallic sources. The morphology and crystalline quality of the films show no evidence of degradation upon iron doping. Mössbauer and spin resonance experiments demonstrate that the Fe-impurity is in the isolated Fe3+ paramagnetic state and no Fe-precipitates are formed at the highest doping levels. Low temperature photoluminescence studies are consistent with full compensation of the shallow pervasive Si and O donors. [ABSTRACT FROM AUTHOR]

High quality monocrystalline indium oxide (In 2 O 3 ) films have been epitaxially grown on SiO 2 (0001) substrates by the metal-organic chemical vapor deposition (MOCVD) method. The influences of different growth temperatures on the structural, morphological and optoelectronic properties of the films were studied in detail. The film deposited at 650 °C exhibited the narrowest X-ray linewidth with an epitaxial relationship of In 2 O 3 (1 1 1)∥SiO 2 (0001). The highest Hall mobility of 27.84 cm 2  V −1  s −1 with a minimum carrier concentration of 5.03 × 10 19  cm −3 and a minimum resistivity of 4.24 × 10 −3  Ω cm was obtained for the film prepared at 650 °C. The average transmittance for all the samples in the visible range exceeded 82% and the optical band gap of the films was calculated about 3.7 eV. [ABSTRACT FROM AUTHOR]

The forming conditions of natural jadeite were simulated with a reasonable synthetic process. According to the molecular composition of purple jadeite, Al 2 (SiO 3 ) 3 , Na 2 SiO 3 ·9H 2 O and MnO were selected as raw materials which were thoroughly mixed and then quenched at 1100 °C. Finally, the experiments were carried out under the range of 3.5–4.5 GPa and 1200–1500 °C. X-ray diffraction and field emission scanning electron microscopy (FESEM) show that the synthesis of crystalline mineral samples are jadeites with excellent crystallinity and fine-grained texture. The peak positions of infrared spectra and Raman spectra are consistent with those of natural jadeite showing that the synthetic jadeites have the same modes of molecular vibration with natural jadeite. The synthetic jadeite is purple (violet) in color due to MnO absorption indicated by UV–Vis Spectroscopy. The purpose of this experiment is to simulate geological formation conditions of purple jadeite gemstone and to provide favorable synthesis conditions to enable further research on the coloration mechanisms of purple jadeite. [ABSTRACT FROM AUTHOR]

Single crystals of 0.2, 0.4, 0.6, 0.8 and 1 M of ZnSO 4 -added glycine were grown by slow evaporation method and their structural, optical and antimicrobial properties were studied. The incorporation of ZnSO 4 on glycine was confirmed by the Powder X-Ray Diffraction (PXRD) and Fourier Transform Infra Red (FTIR) studies. The lesser molar proportion of ZnSO 4 yields only α polymorph of glycine where as higher molar proportion of ZnSO 4 yields γ polymorph of glycine; this was confirmed by PXRD investigation. The influence of ZnSO 4 on the optical transmission in the visible and Ultraviolet (UV) region was studied by UV–Visible–Transmission spectrum. Nonlinear Optical (NLO) productivity of γ- glycine crystals was studied by Kurtz and Perry technique using Nd: YAG laser. The results revealed increased SHG efficiency with the highest of about 3.7 in the presence of 0.6 M of ZnSO 4 compared to the reference material Potassium dihydrogen orthophosphate (KDP) crystal. The antimicrobial behavior of the doped samples were studied using agar diffusion method. [ABSTRACT FROM AUTHOR]

Single crystals of strontium iodide (SrI 2 ), an important material for nuclear detector applications, are grown commercially in cylindrical ampoules using the Bridgman self-seeding method. As a result, the axial orientation of Bridgman boules varies from run to run. Most crystal growth methods benefit from the use of oriented seeds, which can be helpful in maximizing growth rates and crystal quality. However, it is very difficult to orient SrI 2 crystals because they are deliquescent and their surfaces damage easily during cutting and polishing. In this study, unpolished facets formed on an edge-defined film-fed growth (EFG) boule were used to generate the first Laue patterns. The principal boule used in this study had a square cross section and was grown using a seed cut from along the growth axis of a Bridgman boule. X-ray analysis showed that the EFG boule grown from this seed grew along the b-axis and the side facets were the (1 0 0) and (0 0 1) faces. This work made possible the fabrication of oriented SrI 2 seeds for use in future EFG and Czochralski growth experiments and allowed for the determination of the optic axes using polarized light. [ABSTRACT FROM AUTHOR]

Bulk crystals of monoclinic Cu 2 Sn 1− x Ge x S 3 were prepared by chemical vapor transport with iodine. The samples were investigated using electron-probe microanalysis, transmission electron microscopy, Raman spectroscopy and X-ray diffraction (XRD). All of the samples had a Cu-rich and S-poor composition. As the Ge content increased, the XRD peaks shifted to higher angle, the Raman peaks shifted to higher wavenumber, and the lattice constants decreased. Selected-area electron diffraction patterns showed that the samples were single crystal and had a monoclinic structure. [ABSTRACT FROM AUTHOR]

Powder and polycrystals synthesized from Ga, Se, Er components, as well as GaSe and GaSe:Er single crystals grown from melt in argon atmosphere and in vacuum, respectively, are studied. The growth and quenching conditions used in this work provide 2.5 times increase in solubility of erbium in GaSe matrix and a decrease in number of phases to GaSe and Er 2 Se 3 , oppositely to multiphase GaSe:Er alloys known from literature. For the first time Er 2 Se 3 phase was detected by XRD in GaSe crystal doped with 1 at%Er. Possible orientation relations are derived for Er 2 Se 3 /GaSe epitaxial pair. It has been shown that stretched reflections in electron micro diffraction patterns and scattering of maximums in x-ray diffraction patterns are bound to stacking faults, which appear owing to thin interlayers of δ-GaSe polytype in ε-GaSe matrix of the melt-grown crystals. Morphology of growing crystal surface is studied. Photoluminescence spectra of pure and erbium-doped GaSe display intense photoluminescence bands, which are, presumably, associated with defect states in band gap of GaSe. It is shown that doping with Er has a strong effect on photoluminescence intensity and on its spectral composition. The measured 1.7 times increase in Vickers microhardness (up to 400 MPa) with respect to pure GaSe is due to solid solution hardening and to precipitation. [ABSTRACT FROM AUTHOR]