Collaboration :: By country 

    :: Bulgaria


B U L G A R I A N    A C A D E M Y    O F    S C I E N C E S

International Scientific Cooperation

Serbia and Montenegro 
Partner of BAS:
Institute of Physics 




Title: Raman scattering and photoluminescence from semiconductor nanoparticles

Research partners: 
Institute of BAS:
G. Nadjakov Institute of Solid State Physics 
Partner institute: 
Institute of Physics Center for Solid State Physics and New materials
Postal code and address: Tzarigradsko chaussee Blvd., 1784 Sofia, Bulgaria
Postal code and address: 11080 Belgrade/ Zemun, PP 68, Pregrevica Str. 118
Director: Prof. Dr.Sci. Alexander G. Petrov  Director: 
Institute of Physics: Prof. Dr. Dragan Popovic Center for Solid State Physics and New materials: Prof. Dr. Zoran V. Popovic
Project coordinator: Assoc. Prof. Dr. Diana Dimitrova Nesheva-Slavova  Project coordinator: Prof. Dr. Zoran V. Popovic
 +359 (2) 7144 226  (+381-11) 3160598
Fax: +359 (2) 9753 632  Fax: (+381-11) 3162190
e-mail:  e-mail: 
Beginning:1.05.2003  Duration: three years


Present state of knowledge in the field, significance and objectives of the joint research:

     Bulk composites of Si or CdSxSe1-x semiconductors and oxide glasses and thin films have been the focus of intensive research because of their room temperature photo- and electroluminescence, which are interesting for practical uses. It is important that in such systems the wavelength of the emitted light may be changed merely by changing the nanocrystallite size. They also demonstrate a high and fast optical nonlinearity interesting for signal processing or designing of optical communication systems. Moreover the CdSe-glass composites are suitable for studying quantum size effects in quasi-zero dimensional systems (quantum dots). 

     The ability to control the size and structure of nanoparticles would allow the fabrication of structures with desired electrical and optoelectronic properties for device applications. Raman scattering provides a fast and non-destructive method to determine whether semiconductor nanoparticles are amorphous or crystalline. Moreover, information about nanocrystallite size can be obtained from the shape and peak position of the first order Raman scattering band. The “finite size effects”, which destroy the full translation symmetry of the material, result in a low-frequency asymmetric broadening and red shift of the Raman band. Thus, from the details of the Raman line shape the nanoparticle size could also be evaluated.

     In this project, SiOx thin films with various oxygen contents (1.1 - 1.7) as well as GeS2-CdSe multilyer structures will be produced by thermal evaporation in vacuum. Amorphous and crystalline silicon nanoparticles will be grown in the SiOx films upon rapid thermal annealing the films at various temperatures and for various times. Raman scattering and photoluminescence measurements will be carried out on both kinds of films. 

(up to 4): 
Si nanoparticles, GeS2-CdSe multilayer structures, Raman scattering, Photoluminescence

Background of cooperation and envisaged results and benefit:

     The great interest to the new properties and deverse real and potential applications of nanomaterias are the basis for the mutual interest to this collaboration project. The experience of both laboratories in Raman scattering studies of semiconductor superlattices and nanoparticles will facilitate joint research. Common studies have already been performed on SiOx-CdSe composite films comrising CdSe nanocrystals of various average sizes (D. Nesheva, C. Raptis, Z. Levi, Z. Popovic, I. Hinic, “Photoluminescence of CdSe nanocrystals embedded in a SiOx thin film matrix”, J. Luminescence, 82, 233 (1999).)
   It is expected: i) new, relatively cheap, techique for synthesis of Si nanoparticles in SiOx thin film matrix to be developed; ii) useful information to be obtained on size-induced changes in optical and vibrational properties of GeS2-CdSe multilayer structures and Si nanoparticles grown in a SiOx matrix. 

Relation to other projects (partners, titles, duration, and funding):


Research plan for the first year:

     Preparation of SiOx films with oxygen content, x, varying between 1.1 and 1.7 by thermal evaporation of SiO in vacuum;· growth of amorphous silicon nanoparticles upon furnace annealing of SiOx films at several temperatures, T, in the range 673-973 K for various times;· growth of silicon nanocrystals upon rapid thermal annealing at T³ 1270 K;· Photoluminescence and Raman scattering measurements in both sets of films.

Preliminary research plan for the second year:

     Preparation of GeS2-CdSe superlattices and composite films with various CdSe layer thicknesses and average nanoparticle sizes by thermal evaporation of SiO in vacuum;· Photoluminescence measurements and Raman scattering on both sets of films.

Preliminary research plan for the third year:

     Preparation of SiOx films with oxygen content, x, varying between 1.1 and 1.7 by thermal evaporation of SiO in vacuum;· growth of silicon nanoparticles by laser beam annealing for various times;· Photoluminescence and Raman scattering measurements in both sets of films.
Scientific staff involved in the project:
From the Bulgarian side:  From the partner side:
Assoc. Prof. Dr. Diana Nesheva-Slavova
Dr. Zdravka Aneva, researcher
Zelma Levi, researcher
Irina Bineva, chemist
Assoc.Prof. Dr. Georgy Beshkov  
Prof. Dr. Zoran V. Popovic
Dr. Goran Stanisic
Dr. Ivana Hinic
Dr Zorana Dohcevic-Mitrovic
Aleksandra Milutinovic


Annexes: Our findings will be disseminated by joint publications in scientific journals and presentations at scientific conferences. We expect the study at this stage to provide scientific rather than commercial outcomes; it may be possible that subsequent work based on these findings will address such commercial issues. Should this be the case, then IPR policies extant at each institute will be observed.


On behalf of BAS:  On behalf of
Project coordinator:  Project coordinator: 
Signed in: 
Signed in: 

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