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Voronezh State University - Spontaneous atomic ordering in epitaxial compound semiconductor alloys and multilayered heterostructures under the influence of internal stresses as a step to thermodynamically stable structure

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Date of filling in 27.11.2007
Organization name Voronezh State University
Organization adress Universitetskaya pl., 1, Voronezh, 304006, Russia
Department/Unit Chair of solid state physics and nanostructures
Contact person Seredin Pavel, PhD
Phone +7-4732-208363
Fax +7-4732-208363
E-Mail paul@phys.vsu.ru
Web-site http://www.vsu.ru
Organization type
  • Research
  • Education
Special Programme
Theme
Nanosciences, nanotechnologies, materials and new production technologies (NMP)
Call identifier
Topic number Spontaneous atomic ordering in epitaxial compound semiconductor alloys and multilayered heterostructures under the influence of internal stresses as a step to thermodynamically stable structure
Call Deadline -
Short description of the organization (max 12 lines): -
Expertise offered It is supposed that the purpose of the project is studying by a number of the experimental (including synchrotron radiation) and calculated methods of the phenomena of the ordered arrangement of atoms corresponding to the appearance of thermodynamically stable structure in the strained epitaxial structures of ternary and quaternary systems of semiconductor alloys. The urgency of a problem of ordering is related to the modification of the fundamental properties of semiconductors at transition to nanosystems due to reducing of symmetry of zinc blende structure in А3В5 in compounds in nanolayers resulting in a possible decrease of the band gap, transition from indirect to direct band gap semiconductor, an inverse sequence of bands, complication of X-ray absorption and infrared (IR) spectra of superstructure phases as a result of removal of degeneration from the states corresponding to the valence band top and the bottom of conduction band. It is expected, that during performance of the project it will be demonstrated that the atomic configurations arising in nanosystems of semiconductor alloys of superstructure phases minimize the energy of mechanical stresses appeared due to mismatch of lattice parameters of the components comprising the alloy whereas the random arrangement of atoms does not provide such minimization.
Problems to be solved and results: During performance of the project it is expected to gain the following scientific results: - Optimum thermodynamic and kinetic parameters for obtaining of superstructure phases in epitaxial nanolayers of different semiconductor alloys will be determined; - Influence of the growth parameters (growth temperature, growth rate, ratio of concentrations of the elements of third and fifth groups) on formation of superstructure phases in epitaxial nanolayers will be investigated; - Influence of crystalline orientation of a substrate on the features of formation of superstructure phases in epitaxial nanolayers will be studied; - Influence of composition differentiating (in the range of x=0.50) on the content of superstructure phases in nanolayers will be investigated; - Photoluminescence properties of nanosystems, containing superstructure phases will be examined; - Superstructural phases will be identified by X-ray diffractometry and X-ray probe microanalysis; - Precise determination of parameters of superstructure phases will be performed by radiographic analysis and X-ray diffractometry method; - Nanostructure of the investigated objects will be determined and some features of nanomorphology of the ordered areas in the epitaxial alloys will be revealed with use of atomic force microscope; - Performing of the calculations of the relative energy for elastic mechanical stresses of crystalline lattice forming the ordered atomic fragments, i.e. superstructure phases; - Specified a sequence of energy zone and peculiarities in density of states distribution based on X-ray absorption near edge structure (conducting band) and XPS (valence band) data, band-gap energy of new superstructures phases will be determined.
Scientific keywords Semiconductors Heterostructures Spontaneous ordering Quantum dots GaN AlGaN GaInAsP GaInP AlGaAs
Publications on the topic (other references) 1. E. P. Domashevskaya, P. V. Seredin at al. Vegard’s law and superstructural phases in AlxGa1−xAs/GaAs(100) epitaxial heterostructures. // Semiconductors. Volume 39, Number 3 2005 2. E. P. Domashevskaya, P. V. Seredin at al. XRD, AFM and IR investigations of ordered AlGaAs2 phase in epitaxial AlxGa1-xAs/GaAs (100) heterostructures// Surface and Interface Analysis Volume 38, Issue 4 , Pages 828 - 832 3. E. P. Domashevskaya, P. V. Seredin at al. Infrared reflectance spectra and morphologic features of the surface of epitaxial AlxGa1−xAs/GaAs(100) heterostructures with the ordered AlGaAs2 phase //Semiconductors. Volume 40, Number 4 2006 4. P. V. Seredin, E. P. Domashevskaya at al. IR-spectra multilayered epitaxial heterostructures with embedded layers In As and GaAs// Semiconductors. accepted manuscript – article in press, 2008. 5. E. P. Domashevskaya, P. V. Seredin at al. Scaled nano- and a microrelief of fields of streamlining in epitaxial heterostructures AlxGa1-xAs/GaAs (100)// Journal of Surface Investigation. X-ray, Synchrotron and Neutron Techniques., accepted manuscript – article in press, N2, 2008 6. E. P. Domashevskaya, P. V. Seredin at al. Investigations of porous InP properties by XRD, IR, USXES, XANES and PL techniques//Material Science and Engineering B, accepted manuscript – article in press; published online: http://dx.doi.org/10.1016/j.mseb.2007.08. 029 (DOI:10.1016/j.mseb.2007.08.029).
Description of previous and present experience in International Cooperation -
Previous participation in EU’s Framework Programme projects