Selective methods formation of nanoparticles chalcogenide semiconductors 14 January 2006

MUSTAFA B.MURADOV Baku State University NanoCentre Z.Khalilov 23, Baku, AZ1148, AZERBAIJAN

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

Selective methods of growth Allow to operate the sizes of particles at level of monomolecular layer Atomic-layered epitaxy Atomic-layered epitaxy Chemical assembly Chemical assembly Ion-layered chemisorptions Ion-layered chemisorptions

Ion-layered chemisorptions (One cycle of formation) Adsorptions of cations on surface (volume) of substrate Adsorptions of cations on surface (volume) of substrate Washing residue of electrolytes with the solvent Washing residue of electrolytes with the solvent Adsorptions of anions on surface (volume) of substrate Adsorptions of anions on surface (volume) of substrate Washing residue of electrolytes with the solvent Washing residue of electrolytes with the solvent

Process of growth Nanoparticles growth Nanoparticles growth H2OH2OH2OH2OH2OH2OH2OH2O CuSO Fig.1а 1-glass substrate 2-gelatin film Na 2 S

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

Thermodynamics of prosses Thermodynamics of prosses µ Cun =µ Cus µ Cun =µ Cus µ Cun -chemical potential of copper in nanoparticles, µ Cus - chemical potential of copper in solutions µ Cun -chemical potential of copper in nanoparticles, µ Cus - chemical potential of copper in solutions µ=µ 0 +kT lnC µ=µ 0 +kT lnC C- concentration of solutions, T-temperature, µ- chemical potentials, µ 0 -standard chemical potentials of particles, k- Boltzmann constant

The transmission spectra of samples CdS:gelatin/glass, dashed line after thermal annealing (T=90C, t=30min), d=30-200A, ∆E=0.7eV

The change of refractive index structure CdS:gelatin

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

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

REFERENCE 1. 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 (in Russian) 3. 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). 2. J. Puiso, S. Tamulevicius, G. Laukaitis, S. Lindroos, M. Leskela, V. Snitka Growth of PbS thin films on silicon substrate by SILAR technique Thin Solid Films 403 –404 (2002) 457–461 4.M.B.Muradov, V.L.Smirnov, V.A.Karavanskii Patent USSR N , 1986;. 5. 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.

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