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New Trends in Solvothermal Crystal Growth Processes

New Trends in Solvothermal Crystal Growth Processes International Seminar on Material Synthesis and Processing (ISMSP-2008) Taipeh (TAIWAN), 26-27 march 2008.

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New Trends in Solvothermal Crystal Growth Processes

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  1. New Trends in Solvothermal Crystal Growth Processes International Seminar on Material Synthesis and Processing (ISMSP-2008) Taipeh (TAIWAN), 26-27 march 2008 Professor Gérard DEMAZEAUEméritus ProfessorInstitut de Chimie de la Matière Condensée de BORDEAUX (ICMCB)Centre National de la Recherche Scientifique (CNRS)Université BORDEAUX 1 « Sciences et Technologie »site de l’ENSCPB (National Engineer School of Chemistry and Physics) Adress: 87 Avenue du Dr A. Schweitzer 33608 PESSAC-Cedex (FRANCE)e-mail: demazeau@icmcb-bordeaux.cnrs.frFax: 33 5 40 00 27 10 International Hydrothermal Solvothermal Association ISHA

  2. New Trends in Solvothermal Crystal Growth Processes • Definition of solvothermal processes and Main scientific domains involved • Solvothermal Processes and the synthesis of novel Materials • Solvothermal Processes and Crystal growth • III-1)Macroscopic scale and Nano-scale • III-2)Crystal growth at the Macroscopic scale • III-2-1)General features characterizing the solvothermal growth of large single crystals.(Principle,History, Main factors , Main Defects….) • III-2-2) Crystal growth of oxides and non-oxides • III-2-3) Crystal growth of oxides (α-quartz,quartz-like,Calcite,ZnO…) • III-2-4) How very High Pressures can be involved? • III-2-5) Solvothermal Crystal Growth of Nitrides • .

  3. New Trends in Solvothermal Crystal Growth Processes III-3) Crystal Growth at the Nano-scale: How Solvothermal Processes can be used for developing functional morphologies for nano-crystallites ? Some examples : 1D morphology : ZnO, InAs,PtFe nanocrystallites. IV) Conclusions:

  4. New Trends in Solvothermal Crystal Growth Processes • Definition of solvothermal processes and Main scientific domains involved • Solvothermal Processes and the synthesis of novel Materials • Solvothermal Processes and Crystal growth • III-1)Macroscopic scale and Nano-scale • III-2)Crystal growth at the Macoscopic scale • III-2-1)General features characterizing the solvothermal growth of large single crystal.(Principle,History, Main factors , Main Defects….) • III-2-2) Crystal of oxides and non-oxides • III-2-3) Crystal growth of oxides (α-quartz,quartz-like,Calcite,ZnO…) • III-2-4) How High Pressures can be involved? • III-2-5) Solvothermal Crystal Growth of Nitrides • .

  5. New Trends in Solvothermal Crystal Growth Processes SOLVOTHERMAL PROCESS The term « SOLVOTHERMAL » was proposed at the beginning of the 90’s (G. DEMAZEAU et al.) during the development of non-aqueous solvents. Examples.  Synthesis and crystal growth of nitrides using liquid ammonia (NH3) as solvent  ammothermal process !  Synthesis and crystal growth of Fe3O4 as small single crystals using C2H5OH as solvent  alcoholothermal process…! Consequently each solvent can lead to a specific « word » for different processes characterized by the same features. SOLVO – THERMAL Solvent use of the temperature

  6. New Trends in Solvothermal Crystal Growth Processes DEFINITION OF A SOLVOTHERMAL PROCESS « Solvothermal process » is the generic term used for describing : « a reaction between one (or several) precursor(s) in presence of a solvent (aqueous = hydrothermal or non aqueous) in a closed vessel at a temperature higher than the boiling temperature of this solvent »   Consequently high pressures are involved. The system can be: insubcriticalor insupercriticalconditions of the solvent,homogeneousorheterogeneous.

  7. New Trends in Solvothermal Crystal Growth Processes SOLVOTHERMAL PROCESSES • Solvothermal processes have been developed in different domains: • Synthesis of novel materials (new composition and new structure).If the synthesis is kinetically controled  stabilization of metastable materials.Ex:Synthesis of layered oxides isostructural to natural phyllosilicates[P. REIG,G. DEMAZEAU, R. NASLAIN J. Mater. Sci. 32, 4189 (1997)] Deposition of thin or thick filmsEx:Ammothermal synthesis of thick Gallium nitride films employing acidic mineralizersD. EHRENTRAUT et al. J. Mater. Sci. (online) Low-temperature sinteringprocesses(N. YAMASAKI, K. YANAGISAWA) • Development of new processes for preparing functional materialsEx: Solvothermal synthesis of cubic boron nitride (c-BN).S. DONG et al. Mater. Lett. 58, 2791 (2004),X.P. HAO et al. J. Cryst. Growth 241, 124 (2002) Solvothermal synthesis of diamond.S. KORABLOV, K.YOKOSAWA, D.KORABLOV, K.TOHJI, N.YAMASAKI Mater.Lett.60,3041(2006) Solvothermal crystal growth Preparation of nano-crystallites well defined in size and morphologyY.T.QUIAN,Y.L.GU,J.LU “The chemistry of nano-materials” Chap.7 (Eds.C.N.R. RAO et al.)

  8. New Trends in Solvothermal Crystal Growth Processes • Definition of solvothermal processes and Main involved scientific domains • Solvothermal Processes and the synthesis of novel Materials • III) Solvothermal Processes and Crystal growth • IV-1)Macroscopic scale and Nano-scale • IV-2)Crystal growth at the Macoscopic scale • IV-2-1)General features characterizing the solvothermal growth of large single crystal.(Principle,History,Main factors,,Defects…) • IV-2-2) Crystal of oxides and non-oxides • IV-2-3) Crystal growth of oxides • (α-quartz, quartzlike, Calcite, ZnO…) • IV-2-4) How High Pressures can be involved? • IV-2-5) Solvothermal Crystal Growth of Nitrides • .

  9. New Trends in Solvothermal Crystal Growth Processes SOLVOTHERMAL PROCESSES IN MATERIAL SYNTHESIS • Solvothermal preparation of new materials.Example: Synthesis of Phyllosiloxides: layered oxides isostructural of the natural phyllosilicates. • Solvothermal synthesis of metastable materials. Due to the increase of the chemical reactivity, the synthesis can be kinetically controlled. • Solvothermal synthesis of hybride materials. inorganic/organic systems,  inorganic/biological systems.

  10. New Trends in Solvothermal Crystal Growth Processes Solvothermal preparation of new materials Synthesis of a new class of oxides: The PHYLLOSILOXIDES HISTORY :!!!!The first objective: interphase(fiber/matrix) in composite materials to deviate the cracks issued from the matrix mode 1 mode 2

  11. Solvothermal preparation of new materials Synthesis of a new class of oxides: The PHYLLOSILOXIDES - Two different criteria for such an interphase: layered structure=”mechanical fusible” thermal stability (T≈1000°C) in oxidizing atmosphere - Analysis of the available layered materials It is difficult to improve the stability vs. oxygen for graphite and h-BN. Consequently only one way: How to improve the thermal stability of the phyllosilicates?

  12. Solvothermal preparation of new materials Synthesis of a new class of oxides: The PHYLLOSILOXIDES The thermal stability of phyllosilicates is limited by OH groups. 2OH- O2-+H2O+ Anionic substitution OH-O2- in the phyllosilicates lattice.But: correlated with cationic substitutions 

  13. Solvothermal preparation of new materials Synthesis of a new class of oxides: The PHYLLOSILOXIDES D • sol-gel process: sol  gel aerogelConventional Solid StateSolvothermal processProcess (500 1000°C) solvent = 2-methoxy-ethanol precursor = aerogelMixture of 3D silicates T=600°C, 50P150MPa, t24h • single phase

  14. Synthesis of a new class of oxides: The PHYLLOSILOXIDES Solvothermal preparation of new materials I.R. Spectroscopy K Mg3 (Si3Al)O10(OH)2 K(Mg2Al) Si4 O12 X. Ray Diffraction Scanning Electron Microscopy H.R.T.M. K(Mg2Al) Si4 O12 K Mg3(Si3Al)O10(OH)2

  15. New Trends in Solvothermal Crystal Growth Processes • Definition of solvothermal processes and Main involved scientific domains • Solvothermal Processes and the synthesis of novel Materials • Solvothermal Processes and Crystal growth • III-1)Macroscopic scale and Nano-scale • III-2)Crystal growth at the Macoscopic scale • III-2-1)General features characterizing the solvothermal growth of large single crystal.(Principle,History,Main factors,Defects….) • III-2-2) Crystal of oxides and non-oxides • III-2-3) Crystal growth of oxides (α-quartz,quartz-like,Calcite,ZnO…) • III-2-4) How High Pressures can be involved? • III-2-5) Solvothermal Crystal Growth of Nitrides • .

  16. New Trends in Solvothermal Crystal Growth Processes • CONCERNING THE CRYSTAL GROWTH: • How Solvothermal Processes can be involved: • the crystal growth of large single crystals (oxides or non oxides) Crystal growth at the macroscopic scalebut also, • the design of functional morphologies for nano-crystals for specific applications. Crystal growth at the nano-scale

  17. New Trends in Solvothermal Crystal Growth Processes • Definition of solvothermal processes and Main involved scientific domains • Solvothermal Processes and the synthesis of novel Materials • Solvothermal Processes and Crystal growth • III-1)Macroscopic scale and Nano-scale • III-2)Crystal growth at the Macroscopic scale • III-2-1)General features characterizing the solvothermal growth of large single crystal.(Principle,History,Main factors,Defects….) • III-2-2) Crystal of oxides and non-oxides • III-2-3) Crystal growth of oxides (α-quartz,quartz-like,Calcite,ZnO…) • III-2-4) How High Pressures can be involved? • III-2-5) Solvothermal Crystal Growth of Nitrides • .

  18. New Trends in Solvothermal Crystal Growth Processes • Definition of solvothermal processes and Main involved scientific domains • Solvothermal Processes and the synthesis of novel Materials • Solvothermal Processes and Crystal growth • III-1)Macroscopic scale and Nano-scale • III-2)Crystal growth at the Macoscopic scale • III-2-1) Solvothermal growth of large singlecrystal.(Principle,History,Main Features Characterizing the crystal growth process…) • III-2-2) Crystal of oxides and non-oxides • III-2-3) Crystal growth of oxides (α-quartz,quartz-like,Calcite,ZnO…) • III-2-4) How High Pressures can be involved? • III-2-5) Solvothermal Crystal Growth of Nitrides • .

  19. New Trends in Solvothermal Crystal Growth Processes PRINCIPLE OF THE SOLVOTHERMAL CRYSTAL GROWTH seeds Crystallization zone Diaphragm Dissolution zone nutrient Schematic principle for the Solvothermal Crystal Growth(in the case of a non-retrograde solubility)

  20. New Trends in Solvothermal Crystal Growth Processes BRIEF HISTORY OF THE SOLVOTHERMALCRYSTAL GROWTH OF LARGE SINGLE CRYSTALS • The history of the solvothermal Crystal Growth is closely related to the hydrothermal crystal growth of a-quartz. • due to: • its piezoelectric properties (leading to important applications) • its low temperature domain of stability (Ta-quartz→ Tb-quartz = 573°C) (impeding the use of conventional crystal-growth processes) • The elaboration of a-quartz single crystals was the first example for industrial developments of Hydrothermal Crystal Growth.

  21. New Trends in Solvothermal Crystal Growth Processes BRIEF HISTORY OF THE SOLVOTHERMALCRYSTAL GROWTH • MURCHISON (1792-1871) described the role of H2O under P, T conditions in the formation of rocks and minerals. • SCHAFHÄULT (1845)de SENARMONT (1851) • SPEZIA (1842-1912)(Turin-University) using natural crystal as seeds, solution of sodium silicate, silver-lined vessel T = 320-350°C T- T = 165-180°C200 days a-quartz single crystal = 12 mm.The shortage of natural a-quartz from BRAZIL during the second World War:NACHEN (1884-1971)(Frankfurt University)W.A. and N. WOORTER(Cambridge University) the first single-crystals through a specific well defined process. • Then industrial developments: U.S., RUSSIA, JAPAN.... First attempts for obtaining small a-quartz crystals.

  22. New Trends in Solvothermal Crystal Growth Processes MAIN FACTORS GOVERNING THE SOLVOTHERMAL CRYSTAL GROWTH CHEMICAL FACTORS PHYSICAL FACTORS KINETICAL FACTORS • nature of the solvent,- nature of the nutrient,- nature of the seeds,- the interactions solvent/ wall of the HP. Vessel. - the crystal growth temperature (Tgrowth),- the T value,- the pressure value,- the hydrodynamics in the crystal-growth system. - the kinetics of dissolution,- the kinetics characterizing the diffusion of chemical species,- the crystal growth kinetics,- the duration of the crystal growth.

  23. New Trends in Solvothermal Crystal Growth Processes MAIN DEFECTS EXISTING IN THE RESULTING CRYSTALS: CORRELATIONS WITH THE MAIN FACTORS GOVERNING THE SOLVOTHERMAL CRYSTAL GROWTH PROCESS CHEMICAL DEFECTS - inclusions of another phase, - chemical impurities: substitution Si4+ Mn+ if n = 4+  no charges compensation( physical defects in the vicinity of M4+ versus its size) (ex. Ge4+) if n = 3+ (ex: Al3+) charges compensation →O2- OH-(Hydroxyl-group = O2-/H+) or →M+alkaline ionsnear the M3+ (in interstitial position) PHYSICAL DEFECTS - dislocations (able to trap chemical impurities), - fluids inclusions, - etch-channels…

  24. New Trends in Solvothermal Crystal Growth Processes CORRELATIONS BETWEEN DEFECTS AND THE MAIN FACTORS GOVERNING THE CRYSTAL GROWTH PROCESS CHEMICAL DEFECTSinclusions different phases resulting from the chemical interactions solvent/walls of the HP vessel, chemical impurities contamination of the nutrient and/or chemical composition of the solvent.Different aspects:- the identification of the types of ions participating to the lattice - the incorporation mode : substitutionaly or interstitialy,- the dependence of the concentration of incorporated impurities versus the crystal growth direction and the effect of impurities on growth rate. PHYSICAL DEFECTSdislocations → crystal growth rate (vs. T) (etch-channels)  vacancies?

  25. New Trends in Solvothermal Crystal Growth Processes • Solvothermal growth of large single crystals: → OXIDES → NON-OXIDES (Nitrides)

  26. New Trends in Solvothermal Crystal Growth Processes SOLVOTHERMAL PROCESS FOR GROWINGLARGE SINGLE CRYSTALS • Two different domains:Crystal growth of oxides • a-quartz (for its piezoelectric properties),AlPO4, GaPO4, GaAsO4 (a-quartz-like piezoelectric materials)calcite CaCO3 (optical properties: birefringence and transmission over a wide spectral range)ZnO (wide band gap semiconductor, transparent, dielectric and piezoelectric properties…)some others oxides as: KTiOPO4 (KTP), hydroxyapatite Ca10(PO4)6(OH)2, LaPO4, g-LiBO2, b-BaB2O4, RVO4 (R=Y, Gd), KBe2BO3F2(kBBF), ZrW2O8, a-Fe2O3 Zeolites (crystalline aluminosilicates containing pores and cavities of molecular dimensions used as sorbents catalysts, ion exchange materials…)

  27. New Trends in Solvothermal Crystal Growth Processes SOLVOTHERMAL PROCESS FOR GROWINGLARGE SINGLE CRYSTALS • Crystal growth of non-oxides During these last years, strong efforts have been done for controling the solvothermal crystal growth of GaN using a process derived from a-quartz and ZnO solvothermal crystal growth.Ref.“Prospects for the “ammonothermal” growth of large GaN crystal”T. FUKUDA, D. EHRENTRAUTJ. Cryst. Growth. 305, 304-310 (2007) • Such efforts are supported by the existing or potential applications of GaN (opto-electronics, high frequency-high power electronics, fast-speed communication…)

  28. New Trends in Solvothermal Crystal Growth Processes • Solvothermal growth of large single crystals: →OXIDES → NON-OXIDES (Nitrides)

  29. New Trends in Solvothermal Crystal Growth Processes SOLVOTHERMAL CRYSTAL GROWTHOF LARGE SINGLE CRYSTALS • SOLVOTHERMAL CRYSTAL GROWTH OF OXIDES a-quartz • Different solvents (aqueous solutions) have been investigated - NaOH (1M  4 M) - KOH (1M…) - Na2CO3 - NaHCO3, KHCO3 - KCl - NaCl - NaF -pure water  In these solvents the solubility of the nutrient (polycrystalline SiO2) is increased with temperature.

  30. New Trends in Solvothermal Crystal Growth Processes SOLVOTHERMAL CRYSTAL GROWTHOF LARGE SINGLE CRYSTALS • SOLVOTHERMAL CRYSTAL GROWTH OF OXIDES a-quartz  Nutrient - polycrystalline α-SiO2 - cristobalite • Seeds: natural single crystal of a-SiO2 • Additives- some additives have been used for limiting the concentration of OH groups into the bulk single crystal, in particular Li2CO3… • The thermodynamical conditions (P, T, T) depend closely of the selected solvent. For exemple using NaOH-1M P  150 MPa Tgrowth  380-400°C and T  10°C

  31. New Trends in Solvothermal Crystal Growth Processes SOLVOTHERMAL CRYSTAL GROWTHOF LARGE SINGLE CRYSTALS • SOLVOTHERMAL CRYSTAL GROWTH OF OXIDES a-quartz Among the role of the thermodynamical parameters on the crystal growth of a-SiO2, PRESSURE has not been very investigated. NaOH(1M)Tcroissance = 350°C,T = 10°C,t = 10 days Variation of the IR coefficient a (3500cm-2) for a-quartz (Y cut in the Z region) versus the pressure value used for the crystal growth Conclusion: if P a

  32. New Trends in Solvothermal Crystal Growth Processes SOLVOTHERMAL CRYSTAL GROWTHOF a-QUARTZ Concentration profiles for aluminum using microprobe X- versusthe pressure value used for the crystal growth NaOH(1M)Tcroissance = 350°C,T = 10 °C,t = 10 days

  33. New Trends in Solvothermal Crystal Growth Processes SOLVOTHERMAL CRYSTAL GROWTHOF a-QUARTZ Concentration profiles for aluminum using microprobe X- versusthe pressure value used for the crystal growth NaOH(1M)Tcroissance = 350°C,T = 10 °C,t = 10 days Conclusion: The [Al] if PFar from the perturbated zone near the seed

  34. New Trends in Solvothermal Crystal Growth Processes SOLVOTHERMAL CRYSTAL GROWTHOF a-QUARTZ The increase of the pressure value seems to reduce: - the [hydroxyl groups]  IR - the [Al3+]  microprobe, both being correlated.In parallel Pressure increases drastically the solubility of polycristalline quartz. Consequently the concentration of NaOH can be reduced versus pressure.

  35. New Trends in Solvothermal Crystal Growth Processes SOLVOTHERMAL CRYSTAL GROWTHOF LARGE SINGLE CRYSTALS OF a-QUARTZ NaOH(1M)Tdissolution = 360°C,T = 10 °C,t = 10 days Effect of the pressure value on the growth rate

  36. New Trends in Solvothermal Crystal Growth Processes SOLVOTHERMAL CRYSTAL GROWTHOF LARGE SINGLE CRYSTALS OF a-QUARTZ NaOH(1M)P = 150 MPa,T = 35°C,t = 10 days Conclusion: P , Tgrowth  a Effect of the crystal growth temperature on the IR coefficient at 3500 cm-1 (Z cut)

  37. New Trends in Solvothermal Crystal Growth Processes SOLVOTHERMAL CRYSTAL GROWTHOF LARGE SINGLE CRYSTALS OF OXIDES BERLINITE-AlPO4 Three main differences with a-quartz (1) no natural single crystals are available, the Solubility if the Temperature The solvents generally developed are different (H3PO4 or H2SO4)  in order to “bypass” the lack of natural seeds  berlinite epitaxy on a-quartz seeds have been developed. A.I. MOTCHANY and P.P. CHVANSKIAnnales de Chimie: Science des Materiauxvol. 26 (2001) p. 199-208

  38. New Trends in Solvothermal Crystal Growth Processes SOLVOTHERMAL CRYSTAL GROWTHOF LARGE SINGLE CRYSTALS OF OXIDES GaAsO4 GaAsO4 is characterized by the highest piezoelectric coupling coefficient for a-quartz type materials Permittivity as a function of piezoelectric coupling constant for a-quartz type O. CAMBON, P. YOT, S. RUL, J. HAINES, E. PHILIPPOTSolid State Sciences5 (2003) p. 469-472

  39. New Trends in Solvothermal Crystal Growth Processes SOLVOTHERMAL CRYSTAL GROWTHOF LARGE SINGLE CRYSTALS OF OXIDES GaAsO4 Same problems than that observed for AlPO4. Solubility curve of GaAsO4 in 11.5 mole/l H3AsO4 Tdissolution 190°CTgrowth 235°C O. CAMBON, P. YOT, S. RUL, J. HAINES, E. PHILIPPOT, Solid State Sciences 5, 469 (2003).

  40. New Trends in Solvothermal Crystal Growth Processes SOLVOTHERMAL CRYSTAL GROWTHOF LARGE SINGLE CRYSTALS OF OXIDES CALCITE: CaCO3  The hydrothermal process for growing calcite crystals was developed in different countries:  Russia – VNIISIMS (I.V. NEFYODOVA, V.I. LYUTIN, V.L. BORODIN, P.P. CHVANKI, N.I. LEONYUK) in association with Moscow State University.  US– (Dr R. KIWLOCH, R.F. BELT, R.C. PUTTBACH)  France– (F. GENER, M.C. BRICARD, R. LEMETRE, R. AUMONT)  Japan–  (K. KIKUTA, S. HIRANO)  (K. YANAGISAWA, K. KAGEYAMA, Q. FENG, I. MATSUSHITA)

  41. New Trends in Solvothermal Crystal Growth Processes SOLVOTHERMAL CRYSTAL GROWTHOF LARGE SINGLE CRYSTALS OF OXIDES CALCITE: CaCO3 • Different Solvents have been investigated - NH4Cl, NH4Br - LiCl, NaCl, KCl, CaCl2 - KNO3, NaNO3, Ca(NO3)2, NH4NO3 - K2CO3 - organic salts  Different orientations of seeds have been used seed plates // rhombohedral face (1011),pinacoidal (0001) and prismatic (1120) faces. •  Thermodynamical conditionsT = 250-300°C T 5 - 10°CP  60 – 100 MPa duration  30-120 days

  42. New Trends in Solvothermal Crystal Growth Processes SOLVOTHERMAL CRYSTAL GROWTHOF LARGE SINGLE CRYSTALS OF OXIDES ZnO During these last ten years strong efforts have been developed for preparing high quality single crystals of ZnO. Why? :ZnO is a transparent dielectric, piezoelectric and wide-band gap material sustaining a lot of important applications:piezoelectric transducer, gas sensor, optical waveguides, transparent electrode,  varistor and SAW filter,  UV and blue light-emitting device,  opto-electronic and spintronic devices (due to the direct band gap 3.37eV and large exciton-binding energy 60meV).

  43. New Trends in Solvothermal Crystal Growth Processes SOLVOTHERMAL CRYSTAL GROWTHOF LARGE SINGLE CRYSTALS OF OXIDES ZnO Roughly ZnO single Crystals have been prepared through 3 different methods: • The flux method (molten salts as PbF2, V2O5, MoO3, B2O3…) the temperature 800-1300°C.Main problems: - the crystallinity, the size of the single crystals, the difficulty to separate single crystal and solidified flux… • The chemical vapor transport method : chlorine can be used as gazeous transporting agent: ZnO + Cl2 ZnCl2 + ½ O2 G0 being positive at low temperature and becoming negative at high temperature, transport will proceed through the T. (Tgrowth 950-1000°C, T = 10-100°C)Main problems:- the size and the purity of single crystals.The hydrothermal route

  44. New Trends in Solvothermal Crystal Growth Processes SOLVOTHERMAL CRYSTAL GROWTHOF LARGE SINGLE CRYSTALS OF OXIDES ZnO  The hydrothermal method comparatively demonstrated:(i) the high quality of crystals, (ii) the scale-up is possible on the basis of the hydrothermal crystal growth of a-quartz. • What are the main requirements for hydrothermal growth of ZnO high quality single crystals: use of alkaline solutions (high concentration),  use of a inner container,  nutrient: ceramic or pressed tablets,  main crystallographic orientation for the seeds (0001),  growth conditions T  300-400°C P  10 – 50 MPa,  D. EHRENTRAUT, H. SATO, Y. KAGAMITANI, H. SATO, A. YOSHIKAWA, T. FUKUDA, Progress in Cryst. Growth Charact. Mater. 52 (2006) p. 280-335 L.N. DEM’YANETS, V.I. LYUTIN, J. Cryst. Growth 310 (2008) p. 993-999

  45. New Trends in Solvothermal Crystal Growth Processes SOLVOTHERMAL CRYSTAL GROWTHOF LARGE SINGLE CRYSTALS OF OXIDES ZnO During these last years different research groups have been involved in Solvothermal Crystal Growth of ZnO. US: Air Force Research Laboratory University of New York and Wagner College RUSSIA: VNIISIMS Institute of Crystallography R.A.S. Moscow JAPAN: Tohoku University CHINA: State Key Lab. WuhanGuilin Research Inst. Guilin EUROPE: ICMCB-Bordeaux At the present time 3 in-size bulk ZnO single crystals are accessible.

  46. New Trends in Solvothermal Crystal Growth Processes SOLVOTHERMAL GROWTHOF LARGE SINGLE CRYSTALS OF OXIDES ZnO Main directions of research in order to help the crystal growth of ZnO comparatively with the crystal growth of a-SiO2? The main problem  How to reduce the concentration of the solvent in alkaline hydroxides? →Objective: no liner or no special alloys in order to help the handling of experiments and to reduce the cost.

  47. New Trends in Solvothermal Crystal Growth Processes SOLVOTHERMAL CRYSTAL GROWTHOF LARGE SINGLE CRYSTALS OF OXIDES Solvothermal processes have been developed for the crystal growth of different oxides  g-LiBO2Borate Base materials leading to a variety of optical applications within the deep -UV region. - solvent LiOH (small concentration) C.D. McMILLENet al. J. Crystal Growth 310 (2008) p. 299-305  Hydroxy-apatite Ca10(PO4)6(OH)2- M. ASHOKet al. J. Mat. Sci.: Mater. Med. 18 (2005) p. 895-898  b-BaB2O4 - A.E. KOKHet al. Inorganic Mater. 41 (2005) p. 60-64  PbTiO3- MC. GEZABERT, R.A. LAUDISE, R.E. RIMAN, J. Cryst. Growth 197 (1999) p. 195-203

  48. New Trends in Solvothermal Crystal Growth Processes •  KBe2BO3F2 (KBBF)(this is the only material that can be achieve direct frequency doubling below 200 nm.) - N. YE, D. TANG J. Crystal Growth 293 (2006) p. 233-335 •  ZrW2O8(due to its negative thermal expansion)- Q. XING et al. J. Crystal Growth 283 (2005) p. 208-214 • a-Fe3O3 - L.N. DEMIANETS, S.V. POUCHKO, R.V. GAYNUTDINOV J. Crystal Growth 259 (2003) p. 165-178 • Zeolites- C.S. CUNDY, P.A. COX, Chem. Rev. 103 (2003) p. 663-701 • LaPO4(for bio- imaging applications) - K. BYRAPPA et al. J. Mater. Sci. DOI 10.1007/s 10853-007-2337-8

  49. New Trends in Solvothermal Crystal Growth Processes • Solvothermal growth of large single crystals: → OXIDES How very High Pressures can be sometimes involved? (Basic Researches) → NON-OXIDES (Nitrides)

  50. New Trends in Solvothermal Crystal Growth Processes HOW VERY HIGH PRESSURES HAVE BEEN REQUIRED FOR THE CRYSTAL GROWTH OF SOME OXIDES  Crystal growth of RNiO3 (R= Rare-earth) “Crystal Growth of RNiO3 perovskites under high oxygen pressure and hydrothermal conditions”J.A. ALONSO, M.J. MARTINEZ-LOPE, M.T. CASAIS, A. MUNOZ, A. LARGETEAU, G. DEMAZEAUMRS Spring Meeting 2005 Symposium Y878 (2005) p. Y3.4.1-Y3.4.14 - Using RNiO3 as nutrient (H2O + KClO3) as solvent P  4-6 GPa T  900°C

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