Search

This review provides a summary of the growth, progress, and characterization studies of benzimidazole single crystals and their derivatives. Various methods, including SEST, Vertical Bridgeman, and Sankaran Narayanan methods, were employed to grow organic nonlinear optical (NLO) single crystals of BMZ derivatives. The developed crystals underwent different characterization analyses such as UV-Vis-NIR spectroscopy, microhardness testing, and Second Harmonic Generation. The focus of this review is specifically on the advancement of the NLO characteristics of the BMZ single crystal. [ABSTRACT FROM AUTHOR]

In this article, we discuss the preparation of organic 2-chloro-5 nitroaniline (2C5NA) crystals and their different kinds of physical, chemical, and mechanical properties. The vertical Bridgman approach was used to effectively produce the bulk organic 2C5NA crystal. To produce a good-quality bulk crystal, the shape, dimensions, and cone angle of the ampoule were optimized. Also, the temperature profile was set for the 2C5NA crystal. The growth atmosphere and the lowering rate were identified to obtain a homogeneous mixture of the compounds and initiate the nucleation process. Single-crystal X-ray diffraction (XRD), powder XRD, proton Fourier transform nuclear magnetic resonance (FT-NMR), and Fourier transform infrared investigations were used to confirm the crystal structure, molecular structure, and presence of functional groups in the formed crystal. The formed crystal has a monoclinic crystal structure with the space group P21/c, according to single-crystal XRD analysis. The thermal stability and kinetic parameters were examined using thermogravimetric analysis and differential thermal curves. From dielectric analysis, the electrical conductivity and dielectric behavior of 2C5NA were investigated with variations in frequency and temperature. The organic 2-chloro-5-nitroaniline crystal demonstrates that the indentation size effect is observed in the Vickers micro-hardness test, which was also carried out. [ABSTRACT FROM AUTHOR]

The Cd0.95Mn0.05Te0.98Se0.02 (CMTS) ingot was grown by the vertical Bridgman technique at low pressure. All wafers showed high resistivity, which suggests potential as a room-temperature semiconductor detector. The resistivity of the CMTS planar detector was 1.47 × 1010 Ω· cm and mobility lifetime product of electrons was 1.29 × 10−3 cm2/V. The spectroscopic property with Am-241 and Co-57 was evaluated. The energy resolution about 59.5 keV gamma-ray of Am-241 was 11% and the photo-peak of 122 keV gamma-ray from Co-57 was clearly distinguished. The result shows the first detector-grade CMTS in the world and proves CMTS’s potential as a radiation detector operating at room temperature.

Applications in both science and industry have received increased attention as a result of bulk single crystals with particular orientations. However, due to the instability of organic crystals at high temperatures and stress, there is an interest in growing good-quality bulk single crystals with stable thermal and mechanical properties. Here, the 2-amino 4-methylpyridinium 4-nitrophenolate 4-nitrophenol (2A4MPPP) crystal was prepared employing a single-wall ampoule and the vertical Bridgman technique. Structure and functional groups were determined by XRD, NMR, and FTIR studies. More importantly, detailed thermal and kinetic properties such as activation energy, frequency factor, rate constant, and Avrami exponent are discussed. The mechanical stability and dielectric studies are also demonstrated for the title compound. According to the single crystal XRD investigation, 2A4MPPP is a member of the orthorhombic crystal system with the Pna21 space group. Through the TGA and DTA analyses, it was confirmed that the compound starts to melt at 98 °C and complete melting occurs at 103.3 °C. The dielectric experiments reveal the crystal's poor dielectric constant and high-frequency dielectric loss. Vickers microhardness investigations show that grown 2A4MPPP belongs to the soft materials group. As a result of these findings, the 2A4MPPP crystal should be well suited for usage in thermomechanical, microelectronic, optical communications, and nonlinear optical applications.

To date, 3He gas has been commonly used to detect thermal neutrons because of their high chemical stability and low sensitivity to γ-rays, owing to their low density and large neutron capture cross-section. However, the depletion of 3He gas prompts the development of a new solid scintillator for thermal neutron detection to replace 3He gas detectors. Solid scintillators containing 6Li are commonly used to detect thermal neutrons. However, they are currently used in single crystals only, and their 6Li concentration is defined by their chemical composition. In this study, 6Li-containing eutectic scintillators were developed. CeCl3 was selected as the scintillator phase because of its low density (3.9 g/cm3); high light yield (30,000 photons/MeV); and fast decay time with four components of 4.4 ns (6.6%), 23.2 ns (69.6%), 70 ns (7.5%) and >10 μs (16.3%), owing to the Ce3+ 5d-4f emission peak at approximately 360 nm. Crystals of the CeCl3, LiCl and CaCl2 ternary eutectic were fabricated by the vertical Bridgman technique. The grown eutectic crystals exhibited Ce3+ 5d-4f emission with a peak at 360 nm. The light yield was 18,000 photons/neutron, and the decay time was 10.5 ns (27.7%) and 40.1 ns (72.3%). Therefore, this work demonstrates optimization by combining a scintillator phase and Li-rich matrix phase for high Li content, fast timing, high light yield and low density. [ABSTRACT FROM AUTHOR]

In this article, we discuss the preparation of organic 2-chloro-5 nitroaniline (2C5NA) crystals and their different kinds of physical, chemical, and mechanical properties. The vertical Bridgman approach was used to effectively produce the bulk organic 2C5NA crystal. To produce a good-quality bulk crystal, the shape, dimensions, and cone angle of the ampoule were optimized. Also, the temperature profile was set for the 2C5NA crystal. The growth atmosphere and the lowering rate were identified to obtain a homogeneous mixture of the compounds and initiate the nucleation process. Single-crystal X-ray diffraction (XRD), powder XRD, proton Fourier transform nuclear magnetic resonance (FT-NMR), and Fourier transform infrared investigations were used to confirm the crystal structure, molecular structure, and presence of functional groups in the formed crystal. The formed crystal has a monoclinic crystal structure with the space group P21/c, according to single-crystal XRD analysis. The thermal stability and kinetic parameters were examined using thermogravimetric analysis and differential thermal curves. From dielectric analysis, the electrical conductivity and dielectric behavior of 2C5NA were investigated with variations in frequency and temperature. The organic 2-chloro-5-nitroaniline crystal demonstrates that the indentation size effect is observed in the Vickers micro-hardness test, which was also carried out.

To date, 3He gas has been commonly used to detect thermal neutrons because of their high chemical stability and low sensitivity to γ-rays, owing to their low density and large neutron capture cross-section. However, the depletion of 3He gas prompts the development of a new solid scintillator for thermal neutron detection to replace 3He gas detectors. Solid scintillators containing 6Li are commonly used to detect thermal neutrons. However, they are currently used in single crystals only, and their 6Li concentration is defined by their chemical composition. In this study, 6Li-containing eutectic scintillators were developed. CeCl3 was selected as the scintillator phase because of its low density (3.9 g/cm3); high light yield (30,000 photons/MeV); and fast decay time with four components of 4.4 ns (6.6%), 23.2 ns (69.6%), 70 ns (7.5%) and >10 μs (16.3%), owing to the Ce3+ 5d-4f emission peak at approximately 360 nm. Crystals of the CeCl3, LiCl and CaCl2 ternary eutectic were fabricated by the vertical Bridgman technique. The grown eutectic crystals exhibited Ce3+ 5d-4f emission with a peak at 360 nm. The light yield was 18,000 photons/neutron, and the decay time was 10.5 ns (27.7%) and 40.1 ns (72.3%). Therefore, this work demonstrates optimization by combining a scintillator phase and Li-rich matrix phase for high Li content, fast timing, high light yield and low density.

CsPbBr3 is a promising material for high-performance high-energy radiation detectors with high detection efficiency and good stability. In the ingredient stage of preparing the CsPbBr3 single crystal by the vertical Bridgman technique, the oxygen will adsorb on the surface of raw materials, and gather above the sealed crucible after melting, if the contact between the raw material and the oxygen cannot be effectively isolated, and results in a gradually darker color of the single crystal along the growth direction. The color change does not change the band gap of the CsPbBr3 . The electrical performance test of the upper end section of CsPbBr3 single crystals reveals that the resistivity gradually decreases, and the trap density and carrier mobility gradually increases from the center to the outside of CsPbBr3 single crystals. But the responsiveness to X-rays is unchanged from the center to the outside of CsPbBr3 single crystals. This paper contributes to studies on the growth of high-quality CsPbBr3 single crystals. [ABSTRACT FROM AUTHOR]

We compared thermal stability, open-circuit voltage, short-circuit current, and fill factor values of single-crystal Cadmium telluride (CdTe) grown using the vertical Bridgman (VB) technique and doped with group V elements (phosphorus and arsenic), and group Ⅰ element (sodium), followed by an annealing process. The sodium-doped CdTe maintained a hole density of 1016 cm−3 or higher; after annealing for a long time, this decreased to 1015 cm−3 or less. The arsenic-doped CdTe maintained a hole density of approximately 1016 cm−3 even after the annealing process; however its bulk minority carrier lifetime decreased by approximately 10%. The phosphorus-doped CdTe maintained its properties after the annealing process, ultimately achieving a hole density of ~1016 cm−3 and a minority carrier lifetime of ~40 ns. The characteristics of a single-crystal solar cell were evaluated using a solar cell device that contained single-crystal CdTe with various dopants. The sodium-doped sample exhibited poor interfacial properties, and its performance decreased rapidly during annealing. The samples doped with group V elements exhibited stable characteristics even during long-term annealing. We concluded, therefore, that group V elements dopants are more suitable for CdTe single-crystal-based solar cell applications involving thermal stress conditions, such as space missions or extreme fabrication temperature environments.

In this work, the spectroscopic performances of new cadmium–zinc–telluride (CZT) pixel detectors recently developed at IMEM‐CNR of Parma (Italy) are presented. Sub‐millimetre arrays with pixel pitch less than 500 µm, based on boron oxide encapsulated vertical Bridgman grown CZT crystals, were fabricated. Excellent room‐temperature performance characterizes the detectors even at high‐bias‐voltage operation (9000 V cm−1), with energy resolutions (FWHM) of 4% (0.9 keV), 1.7% (1 keV) and 1.3% (1.6 keV) at 22.1, 59.5 and 122.1 keV, respectively. Charge‐sharing investigations were performed with both uncollimated and collimated synchrotron X‐ray beams with particular attention to the mitigation of the charge losses at the inter‐pixel gap region. High‐rate measurements demonstrated the absence of high‐flux radiation‐induced polarization phenomena up to 2 × 106 photons mm−2 s−1. These activities are in the framework of an international collaboration on the development of energy‐resolved photon‐counting systems for high‐flux energy‐resolved X‐ray imaging. [ABSTRACT FROM AUTHOR]

Abstract: Lithium tantalate, LiTaO3 (LT), single crystal growth by the vertical Bridgman (VB) technique is attempt for the first time. In the present VB‐LT technique, pure platinum crucibles are used in a furnace with a graphite heater and an argon atmosphere. One‐hundred percent solidified crack‐free VB‐LT crystals are successfully grown by composing the initial melts with exactly congruent compositions. The fundamental technical issues for VB‐LT growth are also clarified. [ABSTRACT FROM AUTHOR]

During the growth process of organic crystals, it is easy to induce thermal defects and impurities when using the conventional Bridgman technique. In the present study, a specially designed double-wall ampoule was used to solve this problem. High-quality p-terphenyl single crystals were successfully grown by the vertical Bridgman method with the improved ampoule. Powder X-ray diffraction analyses were performed to evaluate the crystallinity of the grown single crystals. Fluorescence spectrum studies show an enhancement of fluorescence properties due to the improvement in crystalline perfection. [ABSTRACT FROM AUTHOR]

Applications in both science and industry have received increased attention as a result of bulk single crystals with particular orientations. However, due to the instability of organic crystals at high temperatures and stress, there is an interest in growing good-quality bulk single crystals with stable thermal and mechanical properties. Here, the 2-amino 4-methylpyridinium 4-nitrophenolate 4-nitrophenol (2A4MPPP) crystal was prepared employing a single-wall ampoule and the vertical Bridgman technique. Structure and functional groups were determined by XRD, NMR, and FTIR studies. More importantly, detailed thermal and kinetic properties such as activation energy, frequency factor, rate constant, and Avrami exponent are discussed. The mechanical stability and dielectric studies are also demonstrated for the title compound. According to the single crystal XRD investigation, 2A4MPPP is a member of the orthorhombic crystal system with the Pna21 space group. Through the TGA and DTA analyses, it was confirmed that the compound starts to melt at 98 °C and complete melting occurs at 103.3 °C. The dielectric experiments reveal the crystal's poor dielectric constant and high-frequency dielectric loss. Vickers microhardness investigations show that grown 2A4MPPP belongs to the soft materials group. As a result of these findings, the 2A4MPPP crystal should be well suited for usage in thermomechanical, microelectronic, optical communications, and nonlinear optical applications., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

Chalcopyrite of CdGeAs 2 single crystal was grown by a modified vertical Bridgman method with sufficient size and quality, and its optical, electrical and thermodynamic properties are characterized. The transmission is recorded in the 2.3–18 μm range, and the band-gap at room temperature is at 0.56 eV. Non-ideal transparency near 5.5 μm which limited its application severely exists in the front of the crystal. The crystal is p type at room temperature with hole concentrations varying from 10 14 to 10 16 cm −3 . From the results of X-ray diffraction measurements carried out over the range 25–450 °C and thermal dilatometer tests, the thermal expansion coefficients are evaluated. And on this basis the Grüneisen parameters at different temperatures are evaluated and also exhibit anisotropic behavior ( γ a > γ c ). It is found that γ a , γ c , and γ V have some difference between these two kinds of test methods. Using these Grüneisen parameters, lattice thermal conductivities have been deduced by two correction formulas. Meanwhile, specific heat capacity and thermal conductivity of [204] have been obtained as a function of temperature by experiment. [ABSTRACT FROM AUTHOR]

As a promising material for second harmonic generation (SHG) and optical parametric oscillator (OPO), CdGeAs 2 single crystals are difficult to reproducibly grow with low loss optical, particularly in the region of 5.5 μm. In addition, a correlation between processing conditions and absorption has attracted various researchers to focus on this problem. This paper describes a series of etching experiments and Hall measurements which were undertaken to see if there might be a relationship between dislocation density, carrier concentration and optical absorption. In this study, a single crystal was grown by the modified Vertical Bridgman method. The spontaneous nucleation growth direction has been determined as [102]. Etch pit densities (EPD) about 10 5 cm −2 were observed at the edges of the boules, whereas etch pits were almost not found in the center. The distribution of dislocation along the radial direction affected optical homogeneity, and the high EPD caused the low transmittance. Meanwhile, the samples are p type at room temperature with hole concentrations varying from 10 14 to 10 16 cm −3 . A linear correlation between absorption at 5.5 μm and hole concentration is established. The results of these experiments are very useful for improving radial and axial optical uniformity of the crystal grown by modified Vertical Bridgman method. [ABSTRACT FROM AUTHOR]

[Display omitted] • Organic 4-nitrophenol bulk crystal was grown using vertical Bridgman technique. • Monoclinic Crystal structure was identified with the space group of P 21/ c. • Electrical activation energy of 4NP was found as 0.310 eV. • Thermogravimetry and mechanical properties were discussed. The organic 4-nitrophenol bulk crystal was grown using single wall ampoule with the vertical Bridgman technique. The grown-crystal was analyzed by single-crystal XRD, powder-XRD, proton NMR, and FTIR studies to investigate its various properties. Single-crystal XRD evidenced the monoclinic crystal system with the space group of P 2 1/ c. Thermal stability was analyzed using thermogravimetric, differential thermal curves, and kinetic parameters. The dielectric behavior and electrical conductivity were discussed. Vickers micro-hardness tester performed to find the mechanical strength and the hardness tester showed that the 4-nitrophenol crystal obeys the indentation size effect. These results may be used for microelectronics and nonlinear optical device applications. [ABSTRACT FROM AUTHOR]

We compared thermal stability, open-circuit voltage, short-circuit current, and fill factor values of single-crystal Cadmium telluride (CdTe) grown using the vertical Bridgman (VB) technique and doped with group V elements (phosphorus and arsenic), and group Ⅰ element (sodium), followed by an annealing process. The sodium-doped CdTe maintained a hole density of 1016 cm−3 or higher; after annealing for a long time, this decreased to 1015 cm−3 or less. The arsenic-doped CdTe maintained a hole density of approximately 1016 cm−3 even after the annealing process; however its bulk minority carrier lifetime decreased by approximately 10%. The phosphorus-doped CdTe maintained its properties after the annealing process, ultimately achieving a hole density of ~1016 cm−3 and a minority carrier lifetime of ~40 ns. The characteristics of a single-crystal solar cell were evaluated using a solar cell device that contained single-crystal CdTe with various dopants. The sodium-doped sample exhibited poor interfacial properties, and its performance decreased rapidly during annealing. The samples doped with group V elements exhibited stable characteristics even during long-term annealing. We concluded, therefore, that group V elements dopants are more suitable for CdTe single-crystal-based solar cell applications involving thermal stress conditions, such as space missions or extreme fabrication temperature environments. [ABSTRACT FROM AUTHOR]

• CGSim numerical simulation is employed for Φ60 mm ZnGeP 2 growth. • The constructed numerical model can make qualitative and accurate prediction. • Optimal parameters are obtained to guide experimental growth of Φ60 mm ZnGeP 2 crystal. The mid-infrared nonlinear crystals have shown great promise for the usage in the fields of sum frequency generation, optical parametric amplifier and optical parametric oscillator. These motivations are empowered by high-quality ZnGeP 2 optical devices with high second-order dielectric susceptibility, thermal conductivity and hardness. However, the rapid development of large-sized ZnGeP 2 single crystals with high optical quality is limited by traditional time-consuming and unpredictable growth route. Herein, for the first time, a strategy of comprehensive unsteady computer modeling is implemented to stimulate the Vertical Bridgman growth process of large-sized ZnGeP 2 single crystal by the Crystal Growth Simulator (CGSim) software. The accurate simulations of temperature field, crystal growth rate, crystallization interface shape and thermal stress evolution are achieved by using this established numerical model. The accuracy and feasibility have been confirmed by the agreement between stimulated and experimental results of the temperature field curves and crystallization interface shape. The optimal parameters for growing large-sized (Φ = 60 mm) ZnGeP 2 single crystal are determined: pulling speed of 0.3 mm/h, temperature gradient of 5 K/cm and slow cooling regime. The large-sized (Φ = 60 mm) ZnGeP 2 single crystal with better quality is thus successfully obtained in the crystal-growth experiment in our lab, further verifying the accuracy of the constructed numerical model. Our work provides a new way to predict and guide the growth of large ZnGeP 2 single crystal and other similar single crystals. [ABSTRACT FROM AUTHOR]

InAsxSb1−x is an important material to fabricate detectors in the mid wavelength and long wavelength infrared region. The wavelength and the lattice constant for InAsxSb1−x can be tuned in the range of 6.8 µ m–3.5 µ m and 6.478–6.058Å by adjusting the arsenic composition. InAsxSb1−x crystals were grown by the vertical rotational Bridgman technique using GaAs (001) single crystal seed. Growth parameters such as temperature, period, ampoule design modification and cooling rate were analysed and used. A cooling rate of 0.25°C/hr is employed and the temperature of the growth region is carefully selected by suitably varying the temperature program/profile. Thermal pulse striations have been introduced inside the crystal during growth and etching technique was used to determine the real growth rate of the crystal. The chemical homogeneity and infrared transmittance analysis were carried out on the grown crystals. [ABSTRACT FROM AUTHOR]

Good quality GaxIn1−xSb bulk crystals, suitable for infrared (IR) device applications, were successfully grown by using vertical Bridgman technique. A number of experiments were carried out with different ampoule lowering rate, axial temperature gradient and ampoule cone angle in order to optimize the growth conditions. For checking the chemical homogeneity, the grown crystals were subjected to X-ray diffraction (XRD) and energy dispersive X-ray (EDX) analysis. The formation and growth of the crystals was confirmed by the XRD analysis. Chemical etching revealed no observable variation of defect-density distribution. Electrical and optical absorption studies of the grown crystals were also studied. IR transmittance studies revealed the sharp cutoff at shorter wavelength and high-percentage transmittance, which are the essential conditions for the infrared device applications. [Copyright &y& Elsevier]

Trans-stilbene crystals were grown by vertical Bridgman technique with modified growth vessel. Energy response to 60Co and 137Cs was done for the grown crystal. The time resolution study has been carried out for the BGO–stilbene phosphor combine using 22Na (511 keV) gamma source. [Copyright &y& Elsevier]

In this study, group III–V compound semiconductor gallium antimonide (GaSb) crystal is grown by the vertical Bridgman technique. A (111) twinning is generated in the as‐grown crystal due to its polarity behavior as the GaSb crystal has a zinc‐blende structure. Hall effect measurements illustrate that the as‐grown GaSb crystal has n‐type semiconductor behavior among the whole temperature range, and the carrier concentration reaches the highest value of 3.27 × 1018 cm3 at 900 K. Thermoelectric behavior of GaSb crystals along the (111) plane is investigated. It shows the lowest electrical conductivity of 53.2 S cm−1 and the highest Seebeck coefficient of −470.0 µV K−1 at 700 K. However, the largest power factor of 13.7 µW cm K−2 takes place at 600 K. For thermal conductivity (k), the k value always decreases with increasing temperature, and the lowest k that occurred at around 900 K is about 7.44 W m−1 K−1. Finally, a maximum figure of merit of 0.082 is obtained at 700 K. [ABSTRACT FROM AUTHOR]

Crystals of trans-stilbene were grown by vertical Bridgman Technique and tested by X-ray rocking analysis. Low angle grain boundaries were identified for some crystals and they were tested for the performance of scintillation time characteristics. Their performance is compared with grain boundary-free crystals. [Copyright &y& Elsevier]

Crack‐free single crystals of 42°RY‐oriented lithium tantalate, 42°RY‐LiTaO3 (42°RY‐LT), are grown by the vertical Bridgman (VB) technique, using pure platinum bottomless crucibles to avoid cracking the seed crystal. The fundamental technical issues for 42°RY‐LT growth by the VB technique are clarified. [ABSTRACT FROM AUTHOR]