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Selective methods formation of nanoparticles chal c ogenide semiconductors

Selective methods formation of nanoparticles chal c ogenide semiconductors. May 2011, Oulu, Finland. MUSTAFA B.MURADOV Baku State University NanoCentre E-mail: mbmuradov@gmail.com http:// napep.net Z.Khalilov 23, Baku, AZ1148, AZERBAIJAN. NANOPARTICLES.

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Selective methods formation of nanoparticles chal c ogenide semiconductors

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  1. Selective methods formation of nanoparticles chalcogenide semiconductors May 2011, Oulu, Finland

  2. MUSTAFA B.MURADOV Baku State University NanoCentre E-mail: mbmuradov@gmail.com http://napep.net Z.Khalilov 23, Baku, AZ1148, AZERBAIJAN

  3. NANOPARTICLES • New physical and chemical properties • Thermodynamic peculiarities • Opportunities of creation essentially new materials and devices • Opportunity of controlling of physical and chemical properties of materials -By changing of nanoparticle size -By changing of parameters core/shell structure

  4. Selective methods of growth –nanoscale engineering Allow to operate the sizes of thin films and particles at level of monomolecular layer • Atomic-layered epitaxy- 1977 by Dr. Tuomo Suntola, at the University of Helsinki in Finland • Chemical assembly – Aleskovskiy V.B. Synthesis and stechiometry of solid materials. L.: Nauka, 1976, 142p. • Successful ion layered adsorption and reaction (SILAR) -V.F.Nicolau, Appl. of surface Sci. 22/23 (1985) 1061.

  5. Selective methods of growth - ALE • Atomic-layered epitaxy(deposition) -surface controlled, self-limiting method, -nano structures from gaseous precursors, -accurate and simple film thickness control, • -sharp interfaces uniformity over large areas, excellent conformality, good reproducibility, • multilayer processing capability, and high film qualities at relatively low temperatures.

  6. Selective methods of growth – ALE (ALD) • reactant vapours are pulsed onto the substratealternately one at a time, • Allthe process steps are saturative,groups—saturatively forming a tightly bound monolayer onthe surface, • film growth is self-limiting • one cycle – maximum one monolayer

  7. A schematic representation of the basic principle of the ALE process showing the growth of ZnS film from ZnCl2 and H2S Mikko Ritala, Markku Leskela, Nanotechnology 10 (1999) 19–24.

  8. A schematic representation of the basic principle of theALE process showing the growth of ZnS film from ZnCl2 and H2S

  9. Schematic of the Al2O3 ALD process

  10. Main Characteristic features of ALE – one cycle of formation of oxides • 1) metal exposure, • 2) purge, • 3) oxidizing exposure, • 4)purge

  11. GROWTH RATE Erin D. Robertson Doctoral thesis, 2010

  12. Dependence of Growth Rate from Temperature

  13. Growth Rate – Purge time

  14. ALD WINDOW

  15. Temperature window • temperature process window can be identified based on the constant growth rate of the ALD process • low temperatures - low growth rates -necessary value of activation energy -may be high growth rate as result of condensation

  16. Temperature window • High temperatures can lead to the decomposition of the ALD precursor or desorption of the adsorbates before they are reacted with the 2nd reactant

  17. Main Characteristic features of ALE • Self-limiting growth process, • Separate dosing of reagents, • Processingtemperature windowsare often wide

  18. ALE Application • Chemichal modification of surface, • Controlling thickness of thin films, • processing porous substrates, • modify the surfaces of the porous substrates • [28] D.ucs.o C, Khanh N Q, Horv.ath Z, Barsony I, Utriainen M, • Lehto S, Nieminen M and Niinist.o L 1996 J. Electrochem. • Soc. 143 683 • [29] Utriainen M, Lehto S, Niinist.o L, D.ucs.o C, Khanh N Q, • Horv.ath Z E, B.arsony I and P.ecz B 1997 Thin Solid Films • 297 39

  19. SILAR(successive ion layered adsorption and reaction) or Ion-layered chemisorptions (One cycle of formation) • Adsorptions of cations on surface (volume) of substrate • Washing residue of electrolytes with the solvent • Adsorptions of anions on surface (volume) of substrate • Washing residue of electrolytes with the solvent

  20. SILAR - Process of growth

  21. SILAR POSSIBILITY • Thin films -Semiconductors, -Oxide of metals, • Nanocomposites -polymer inorganic nanoparticles composites, -porous materials and nanoparticles.

  22. SILAR POSSIBILITY • Nano Engineering, -changing of physical properties, -surface engineering,

  23. Shell Preparation by SILAR P. Reiss, M. Protie`re and L. Li, small 2009, 5, No. 2, 154–168

  24. ZnO/CdS core/shell structures • STEP1 - ZnO nanowire arrays were grown by a hydrothermal method, • STEP2 - Successive ion layeradsorption and reaction J.Joo, D.Kim, D.YunNanotechnology 21 (2010) 325604

  25. SILAR - ZnO/CdS core/shell structure SEM&TEM images

  26. CdS CuS PERSPECTIVE OF PREPERATION NANOSTRUCTURE • Selective growth process • Sharp boundary between core&shell Ion layered chemisorptions Diffusion boundary between core&shell CdS CuS transformation process Ion-exchange

  27. Features of growth • Opportunity of controlling structure and stochiometric composition with the help of changing thermodynamic parameters of system • Growth of structures in conditions of local thermodynamic equilibrium

  28. Thermodynamics of prossesV.N.Maslov, M.B.Muradov, • µCun =µCus • µCun -chemical potential of copper in nanoparticles, µCus - chemical potential of copper in solutions • µ=µ0 +kT lnC C- concentration of solutions, T-temperature, µ-chemical potentials, µ0-standard chemical potentials of particles, k- Boltzmann constant V.N.Maslov, M.B.Muradov and oth. Thermodynamic and kinetic futures of growth thin films by ion layered chemisorptions. In book “Growth process of semiconductor thin films and crystals”

  29. Thin Films Growth • Growth rate dependence -concentration -temperature -pH • Can we manage the structure of thin films? • Concentration of anions and cations • temperature

  30. Temperature dependence thickness of CdS thin films(dashed line) (Ge substrate) – for bulk CdS-T=1278K, for ZnS T=1430K

  31. Temperature dependence of angular orientation microcrystallites (CdS/Ge)

  32. Dependence of refractive of CdS thin films from thickness and growth condition A.M.Kutepov, V.N.Maslov, V.S.Pervov, M.B.Muradov, Fractal growth of cadmium sulfide films during ionic-layered chemisorption,Doklady Akademii Nauk SSSR, 1989 v.304, №4, p.1900-1903(in Russian)

  33. NANOCOMPOSITES • Matrix (Polymer, Inorganic porous materials) • Active chemical groups for sorption of cations or anions, • Chemical modification of polymers or other matrix for creating active chemical groups

  34. Materials for Creating of Nanocomposites • Polymers -Polyvinyl alcohol, -Gelatine, • Semiconductor Nanoparticles -CdS, CdSe, CuS

  35. The transmission spectra of samples CdS:gelatin/glass, dashed line after thermal annealing (T=90C, t=30min), d=30-200A, ∆E=0.7eV M.B. Muradov, A.A. Agasiyev, Formation of cadmium sulfide particles in te volume of polimeric matrix., Pisma v Zhurnal Technicheskoy Fiziki 1991,v.17, issue.13, p.54-57(in Russian).

  36. SILAR - The change of refractive index structure CdS:gelatin M.B.Muradov, V.L.Smirnov, V.A.Karavanskii Patent USSR N1448914, 1986;.

  37. Dependence of (αhν)2 from hν; a)1 - 6, 2- 10,3- 15cycles; b)1- 1, 2-4cycles of formation; ∆E=0.45eV; d≥11A M.B.Muradov, G.M.Eyvazova,N.H.Darvishov,S.E.Bagirova Some optical properties of nanoparticles copper sulphide, formed in volume of a polymeric matrix, Transaction NAS Azerbaijan, ser. Physical-mathematical and technical science, 2004,№5.

  38. Cd(NO3)2 concentration is constant M.B.MURADOV, G.M.EYVAZOVA, A. N. BAGIROV, The effect of solutions concentrations on the opticalproperties of CdS nanoparticles formed in the polymericmatrix, JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS Vol. 9, No. 5, May 2007, p. 1411 - 1413

  39. Na2S concentration is constant

  40. CdS:gelatin – before thermal annealinghνmax 30-2.3ev;15-2.48ev; 7&10-2.64ev M. B. MURADOV The influence of the type of polymer matrix on thephotoluminescence from cadmium sulfide nanoparticles, OPTOELECTRONICS AND ADVANCED MATERIALS – RAPID COMMUNICATIONS Vol. 2, No. 2, February 2008, p. 85 - 88

  41. CdS:gelatin after thermal annealinghνmax 30-2.34ev; 15-2.48ev;10-2.58ev;7&5 – 2.64ev;3-2.67ev

  42. PL, CdS-gelatin, emission spectra- before thermal annealinghνmax: 7&10 -1.44ev, 15-1.41ev, 30-1.38ev

  43. PL, CdS-gelatin, emission spectra- after thermal annealinghνmax 3-1.61ev, 5-1.56ev, 7-1.44ev, 10 -1.41ev, 15&30-1.37ev

  44. CdS:PB Spectra of excitation, hνmax=2.82 ev

  45. 1-high, 2-mid, 3-low levelCdS:PB before thermal annealinghνmax=1.71 ev

  46. PL-emission spectrahνmax=1.71 ev

  47. Photoluminescence • Intensity of PL depends from • type of matrix, • Annealing temperature, • character of interaction nanoparticles-polymer

  48. CONCULUSION • Self-limited methods are perspective tools for nanotechnology, • Nanoscale engineering, • Surface modification, • New methods of formation of complex nanomaterials

  49. THANKS My Colleges: Dr.G.Eyvazova, Dr.N.Darvishov Mrs. S.Bagirova. My Students: Azer Bagirov, Yashar Azizian, Nurane Huseynova

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