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Yugov A.A.,State Research and Project Institute of Rare Metal Industry GIREDMET | Malahov S.S.,State Research and Project Institute of Rare Metal Industry GIREDMET | Donskov A.A.,State Research and Project Institute of Rare Metal Industry GIREDMET | Duhnovskii M.P.,Research and Production Corporation Istok | And 4 more authors.
Semiconductors | Year: 2016

The effect of the type of substrate, sapphire substrate (c- and r-orientation) or GaN/Al2O3 template (c- and r-orientations), on the nitridation of an amorphous titanium nanolayer is shown. The effect of the titanium-nanolayer thickness on thick GaN epitaxial layer self-separation from the substrate is revealed. The titanium-nanolayer thickness at which thick GaN layer is reproducibly self-separated is within 20–40 nm. © 2016, Pleiades Publishing, Ltd.


Belogorokhov I.A.,State Research and Project Institute of Rare Metal Industry GIREDMET | Tikhonov E.V.,Moscow State University | Dronov M.A.,RAS A.M. Prokhorov General Physics Institute | Belogorokhova L.I.,Moscow State University | And 3 more authors.
Semiconductors | Year: 2012

The vibronic properties of semiconductor structures based on non-metal naphthalocyanine molecules are studied using IR and Raman spectroscopy methods. New absorption lines in the transmission spectra of such materials are detected and identified. Three transmission lines are observed in the range 2830-3028 cm -1, which characterize carbon-hydrogen bonds of peripheral molecular groups. Their spectral positions are 2959, 2906, and 2866 cm -1. It is detected that the phthalocyanine ring can also exhibit its specific vibronic properties in the Raman spectra at 767, 717, and 679 cm -1. The naphthalocyanine molecule in the organic dielectric matrix of microfibers is described using IR spectroscopy. It is shown that the set of vibrations characterizing the isoindol group, pyrrole ring, naphtha group, and C-H bonds, allows an accurate enough description of the vibronic states of the naphthalocyanine complex in complex heterostructures to be made. The spectral range with fundamental modes, characterizing a naphthalocyanine semiconductor in a heterostructure, is 600-1600 cm -1. A comparison of the compositions of complex systems with a similar heterostructure containing lutetium diphthalocyanine demonstrated few errors. © 2012 Pleiades Publishing, Ltd.


Belogorokhov I.A.,State Research and Project Institute of Rare Metal Industry GIREDMET | Tikhonov E.V.,Moscow State University | Dronov M.A.,RAS A.M. Prokhorov General Physics Institute | Belogorokhova L.I.,Moscow State University | And 3 more authors.
Semiconductors | Year: 2011

Vibronic properties of organic semiconductors based on tert-butyl substituted phthalocyanine lutetium diphthalocyanine molecules are studied by IR and Raman spectroscopy. It is shown that substitution of several carbon atoms in initial phthalocyanine (Pc) ligands with 13C isotope atoms causes a spectral shift in the main absorption lines attributed to benzene, isoindol, and peripheral C-H groups. A comparison of spectral characteristics showed that the shift can vary from 3 to 1 cm -1. © 2011 Pleiades Publishing, Ltd.


Belogorokhov I.A.,State Research and Project Institute of Rare Metal Industry GIREDMET | Tikhonov E.V.,Moscow State University | Dronov M.A.,RAS A.M. Prokhorov General Physics Institute | Ryabchikov Y.V.,RAS Lebedev Physical Institute | And 5 more authors.
Semiconductors | Year: 2011

The transport properties of organic semiconductors based on europium diphthalocyanine and bitris-phthalocyanine complexes with ortho-bis(oxymethyl)phenyl bridge and based on europium and erbium dinaphthalocyanine are studied. The temperature dependences of the dc conductivity for all types of the structures under study are obtained; it is shown that all dependences include two activation portions. For high-temperature portions, the activation energies are determined as 0.85 eV for europium diphthalocyanine with the ortho-bis(oxymethyl)phenyl bridge, 1.135 eV for europium bi-tris-phthalocyanine with the orthobis(oxymethyl)phenyl bridge, 0.98 eV for europium dinaphthalocyanine, and 1.18 eV for erbium dinaphthalocyanine. For the low-temperature activation portion, it is shown that lanthanide ions and their bond with a ligand make the dominant contribution to the conductivity of the structures under study. © 2011 Pleiades Publishing, Ltd.


Gazizov I.M.,Institute of Physical Technical Problems | Zaletin V.M.,Dubna University | Govorkov A.V.,State Research and Project Institute of Rare Metal Industry GIREDMET | Kuznetsov M.S.,State Research and Project Institute of Rare Metal Industry GIREDMET | And 3 more authors.
Semiconductors | Year: 2014

TlBr is a promising wide-gap semiconductor for developing γ-radiation detectors. One of the limiting factors in developing the technology of detectors is the lack of experimentally determined trapping and recombination centers. In this paper, a generalized model of the formation and behavior of intrinsic defects in pure and doped TlBr single crystals is presented. The relation of intrinsic defects to growth conditions and electrical properties is determined. The previously obtained temperature dependences of the photoconductivity, the data of current deep level transient spectroscopy and microcathodoluminescence, and the kinetic characteristics of the photoconductivity are used as objects of analysis. It is shown that the compensation of charged centers control the transport properties of charge carriers. In compensated doped TlBr crystals, the product of the mobility and lifetime can reach μτ = 5 × 10-4 cm2 V-1. The energy-level diagram of local levels in pure and doped TlBr crystals is proposed. The ionization energies of major structural and impurity defects in TlBr, i.e., the anion vacancy V a +, cation vacancy V c -, and Pb2+, O2-, S2- ions, are determined. The energy position of a single anion vacancy Va + is E c - 0.22 eV. The energy level of the cation vacancy is E v + 0.85 eV for a single cation vacancy and E v + 0.58 eV for a vacancy incorporated into the {Pb2+ V c -}0 complex. The ionization energy of the Pb2+ Coulomb trap is E c - 0.08 eV in doped TlBr crystals. © 2014 Pleiades Publishing, Ltd.

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