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Soft chemical synthesis of nanomaterials: challenges for technology transfer in electronic applications

IMNR. Soft chemical synthesis of nanomaterials: challenges for technology transfer in electronic applications. Radu R. Piticescu, Roxana M. Piticescu, National R&D Institute for Non-Ferrous and Rare Metals, Pantelimon, Ilfov, ROMANIA. Presentation content. Introduction

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Soft chemical synthesis of nanomaterials: challenges for technology transfer in electronic applications

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  1. IMNR Soft chemical synthesis of nanomaterials: challenges for technology transfer in electronic applications Radu R. Piticescu,Roxana M. Piticescu, National R&D Institute for Non-Ferrous and Rare Metals, Pantelimon, Ilfov, ROMANIA Al 5-lea Seminar "Nano" 2 martie 2006

  2. Presentation content • Introduction • Problems and barriers in development and applications of hydrothermal procedures for electronic materials • Applications in BST ceramics • Applications in Al-doped ZnO • Conclusions and future works Al 5-lea Seminar "Nano" 2 martie 2006

  3. Nanomaterials market: 490 billion dollars in 2004 and 900 billion dollars in 2005 and 11 trillion dollars in 2010 (annual average grown rate > 10%) The primary of nanomaterials companies material product types and primary market focuses of nanomaterials companies INTRODUCTION Nanomaterials – the driving force, by Michael J. Pitkethly, Market Report, December 2004. Al 5-lea Seminar "Nano" 2 martie 2006

  4. Hydrothermal reactions: chemical processes at high pressures and temperatures over the boiling temperature in aqueous solutions Solvothermal reactions: chemical processes at high pressures and temperatures in non-aqueous solutions Hydrothermal reactions between species in hydrothermal solutions One element M(II)2+(aq) + 2OH-(aq) = MO+H2O; M(II)=alcaline-earth metals: Mg, Ca, Sr, Ba 2M(III)3+(aq) + 6OH-(aq) = M2 O3 + 3H2O; M(III)= Al, Ga, Ln M(IV)4+(aq) + 4OH-(aq) = M O2 + 2H2O; M(IV)= Si, Ge, Ti, Zr, Hf, Mn,... Two elements (ABO3, ABO4,....compounds) xM(II)2+(aq) +y M(IV)4+(aq) +6(x+y)OH-(aq) = M(II)xM(IVy)O3 + 3(x+y)H2O; xM(III)3+(aq) + yM’(III)3+(aq) +6(x+y)OH-(aq) = xM(III)2 yM’(III)2 O3(x+y) + 3(x+y)H2O Hydrothermal crystallisation: transformation of amorphous species in crystalline ones (under the influence of temperature and pressure): M(OH)n = MOn/2 +(n/2) H2O INTRODUCTION Al 5-lea Seminar "Nano" 2 martie 2006

  5. M.Yoshimura, W.Suchanek, Solid State Ionics 98 (1997), pp. 197-208 Problems and barriers in development and applications of hydrothermal procedures for electronic materials • STRENGTHS OF HYDROTHERMAL SYNTHESIS • One step process • Minimize energy consumption • Closed systems, low environmental impact • Products with much higher homogeneity than solid state processing Al 5-lea Seminar "Nano" 2 martie 2006

  6. U/I Hydrothermal deposition PT; PZ; ST; BT Electrophoretic deposition PT; PZ; ST; BT Cathode Reference Anode Problems and barriers in development and applications of hydrothermal procedures for electronic materials STRENGTHS OF HYDROTHERMAL SYNTHESIS Any shape, any size (combining with other external driving forces, e.g. electrochemical) R.R. Piticescu, R.M. Piticescu, Workshop COST D30, Turin, 26-28 Feb. 2004 Al 5-lea Seminar "Nano" 2 martie 2006

  7. log Ai= Hi +BZi + Pi Ji is the stoechiometric coefficient of species “i” in the reaction “j” G0f is the standard free enthalpy of formation of reacting species AJi mAi is the molar concentration of species Ai the solution i is the activity coefficient Lencka and Riman (Rutgers Univ), J.Am.Ceram.Soc, 76, 10, 2649-59 (1993) Problems and barriers in development and applications of hydrothermal procedures for electronic materials • WEAKNESSES • Prediction: Lack of thermodynamic data (only for ideal solutions, low valence ions) Al 5-lea Seminar "Nano" 2 martie 2006

  8. 125C 150C -ln (1-)= kt m 200C Problems and barriers in development and applications of hydrothermal procedures for electronic materials • WEAKNESSES • Prediction: Kinetic limitations Roxana M. Piticescu, R. R. Piticescu, D.Taloi, V. Badilita, Nanotechnology vol. 14 (3), pp. 312-17 (2003) R.R. Piticescu, C. Monty, D. Taloi, D. Millers, Sensor and Actuators B, 109 (1), 102-6 (2005) Al 5-lea Seminar "Nano" 2 martie 2006

  9. Problems and barriers in development and applications of hydrothermal procedures for electronic materials OPPORTUNITIES VERSATILITY:Oxides, non-oxides, organic/biologic materials; hybrid materials HYDROTHERMAL SYNHTESIS IS ONE OF THE VERY FEW METHODS ABLE TO GENERATE NEW MATERIALS OR MATERIALS WITH RADICALLY NEW PROPERTIES Recent examples: new ultra-hard materials (e.g. BC2N)[1] some of which can be doped for semiconductor (e.g. p- and n- doped cubic-BN)[2] or opto-electronic (e.g. cubic-Si3N4)[3] applications,. ANi3+0.98Fe0.02O3 (A=Nd, Lu) perovskites[4] New physical phenomena may be found, for example the perovskite BiNiO3 (prepared at 60 kbar, 1000 °C) shows a unique transition between a metallic state, with charge distribution Bi3+Ni3+O3, and a valence disproportionated and charge ordered insulating state, Bi3+Bi5+(Ni2+)2O6.[5] [1]Solozhenko,V. L., Dub, S. N. & Novikov, N. Diamond Relat.Mater. 10, 2228–2231 (2001) [2]Taniguchi, T. et al. Jpn. J.Appl. Phys. 241, L109–L111 (2002). [3]I.A.Presniakov, G.Demazeau, A.V.Baranov, A.V.Sobolev, K.V.Pokholok., Phys. Rev. B71, 2005, 054409 [4]Gryko, J. et al. Phys. Rev. B 62, 7707–7710 (2000). [5] Ishiwata S, Azuma M, Takano M, et al, J. Mater. Chem. 12, 3733 (2002). Al 5-lea Seminar "Nano" 2 martie 2006

  10. Nucleation and growth • surface diffusion • continuous growth at the kinks • Formation of clusters and critical nuclei • Formation of monolayrers by layer to layer growth W(t) = W0 ( 1 - ekt ) Types of morphologies • Layer or platelate growth • Pyramidal growth • Whiskeres • Dendrites • Epitaxial growth on crystalline substrates • Oriented growth on polycrystalline or amoprphous substrates Unpredictible! Problems and barriers in development and applications of hydrothermal procedures for electronic materials Al 5-lea Seminar "Nano" 2 martie 2006

  11. THREATS Phase separation: additives for agglomeration/de-agglomeration (steric or electrostatic effects) Processing: fine, nanocrystalline powders require high pressures to be compacted special forming technologies elastomer fluid +kT V repulsion V total Vt H -kT V atraction Problems and barriers in development and applications of hydrothermal procedures for electronic materials lack of reliable and standardised characterisation methods; anxiety of end-users vis-à-vis of environmental problems related to nanopowders manipulation Al 5-lea Seminar "Nano" 2 martie 2006

  12. Center of Technological Transfer for Advanced Materials • Identify market requirements for new technologies, services and products in the field of advanced biocompatible and smart metallic, ceramic and composite materials; • Consultancy and expertise in the field of advanced materials; • Participation in elaboration of prognoses in the field; • Encouraging specialized studies for students, masters, PhD students; • Consultancy for SMEs and companies in the elaboration and participation in national and European R&D projects; • Support for SMEs in implementation of European standards for materials Al 5-lea Seminar "Nano" 2 martie 2006

  13. HT synthesis 150 0C/3h; sintering 1250 0C HT synthesis 200 0C/3h; sintering 1250 0C Applications: hydrothermal synthesis of BST Dielectric, piezoelectric and electro-optic properties for applications in the electronic industry: imaging devices, optical memories, modulators, transducers, actuators, high-k dielectric constant materials. Properties strongly dependent on the metallic elemental ratios, impurities, microstructure and grain sizes. Al 5-lea Seminar "Nano" 2 martie 2006

  14. Non-stoichiometric; sintering 1250 0C Stoichiometric composition Nanodomains? A Applications: hydrothermal synthesis of BST Al 5-lea Seminar "Nano" 2 martie 2006

  15. Cathodo-luminescence spectrum (electron beam excitation) with different delay times Fundamental absorption Applications: hydrothermal synthesis of BST Al 5-lea Seminar "Nano" 2 martie 2006

  16. = (C*d)/(0*S) 0=8.85 810-12 farad/m, C-capacity, farad d-thickness, m S-surface area, m2 Applications: hydrothermal synthesis of BST Al 5-lea Seminar "Nano" 2 martie 2006

  17. Applications: synthesis of Al-doped ZnO • Non-stoichiometric (Zn1+xO) • Semi-conducting transparent oxide with a large band gap (3.4eV). Doping with impurities such as Al and In can increase the conductivity of ZnO (large values of electronic carrier density: n~1020cm-3, and mobility: n ~ 1000 cm2V-1). • Piezoelectric properties of zinc oxide thin films can be used in various transducers, acoustic wave and acoustic-optical devices. • Combination of high visible transparency and low electrical resistivity is very useful in applications such as transparent electrodes in solar cells, luminescence display screens, ultraviolet diodes . • When ZnO is in polycrystalline form, luminescence depends on the grain size; ZnO nanomaterials offer from this point of view a new and promising field of investigations. Exciton type and donor-acceptor luminescence Deffect associated luminescence Al 5-lea Seminar "Nano" 2 martie 2006

  18. 0.1 % Al ZnO- hydrothermal precursor 0.1 % Al ZnO vc5- solar furnace Applications: synthesis of Al-doped ZnO R.R. Piticescu, R.M. Piticescu, C. Monty, L. Grjgorieva (under press in J.Eur.Ceram.Soc. 2006) Al 5-lea Seminar "Nano" 2 martie 2006

  19. 0.5 Al% ZnO hydrothermal precursor 0.5 Al% ZnO vc10- solar furnace Applications: synthesis of Al-doped ZnO Al 5-lea Seminar "Nano" 2 martie 2006

  20. Applications: synthesis of Al-doped ZnO Al 5-lea Seminar "Nano" 2 martie 2006

  21. [0002] [0002] [0002] [1010] [1011] [1011] [1010] [1010] [1011] Applications: synthesis of Al-doped ZnO Al 5-lea Seminar "Nano" 2 martie 2006

  22. Applications: synthesis of Al-doped ZnO Al 5-lea Seminar "Nano" 2 martie 2006

  23. PL spectra: two bands – band edge emission (likely of free excitonic and band-to-band and free-to-bound origin) peaked at about 380 nm and a broad band emission (defect related band) peaking at about 520 nm to 600 nm. The broad PL band clearly is due to an overlap of two known ZnO defect related bands – ZnO red PL emission and ZnO green PL emission. The latter dominates in samples with a higher Al fraction. Further studies are required to get a better insight to origin of these two bands and in order to determine conditions of their observations. We noticed that band edge emission is red shifted in nanopowders, as compared to a spectral position of a relevant band in the reference sample. Applications: synthesis of Al-doped ZnO Al 5-lea Seminar "Nano" 2 martie 2006

  24. UV-VIS spectra of 4Al ZnO films Applications: synthesis of Al-doped ZnO Pure and Al doped ZnO has been produced using the hydrothermal method. Lattice constant increased while the density decreases with an increase of Al content. Enhancement of luminescence with increase of Al content (related to a surface passivation or impurity-related defect reaction?) The morphology of the product varied strongly with the synthesis parameters. The vaporisation-condensation technique in a solar reactor from hydrothermal precursors lead to a change of morphology and creation of whiskers. The so-obtained powders/whiskers show brighter light emission, even though the solubility limit of Al decreased comparing to the precursor made using the hydrothermal method. Al 5-lea Seminar "Nano" 2 martie 2006

  25. CONCLUSIONS • Hydrothermal synthesis is a versatile method for producing many nanomaterials with controlled stoichiometry and doping elements concentrations • Hydrothermal + electrochemical: producing of thin/thick films • Hydrothermal + PVD : increase dopant level of elements with low vapour pressure and control morphology • FUTURE PROSPECTS • BST nanomaterials (sintered pellets, thin films): study the role of nanodomains on PL spectra and electrical properties, modeling the device • Al-ZnO nanomaterials (p-type, powders and thin films): electro-optical properties • N-doped (n-type nanomaterials) ? Al 5-lea Seminar "Nano" 2 martie 2006

  26. Future prospects Al 5-lea Seminar "Nano" 2 martie 2006

  27. CONTACT PERSONS • Dr.Teodor Velea, General Director e-mail : tvelea@imnr.ro • Dr. Roxana Piticescu, Lab. Head e-mail : roxana@imnr.ro • Dr. Robert Piticescu, Director Center for Technology Transfer in Advanced Materials e-mail: rpiticescu@imnr.ro • Phone/fax : 0040-21-352.20.48 / 352.20.45  • Address: 102 Biruintei Blvd., Pantelimon, judet Ilfov, Romania Al 5-lea Seminar "Nano" 2 martie 2006

  28. Nanostructured Materials Group – INCDMNR Pantelimon • Dr. C;l;aude Monty –CNRS /PROMES France • Prof. Witold Lojkowski and Dr. Pielaszeck-UNIPRESS Warsaw • Dr. Larisa Grjgorieva and Dr. Vismants Zaulus– Inst. • Solid State Physics Riga • Dr. I. Sajin and Dr. M. Dragoman-Nat. Inst. Mycrotechnologies • Dr. Eugeniu Vasile – METAV CD Bucharest • dr. eng. Maria Giurginca – CNC-UPB, Bucharest thank you EGIDE France – supporting the ECO-Net “Fun-Nanos” project Acknowledgements Thank you for your attention ! Al 5-lea Seminar "Nano" 2 martie 2006

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