Aleksey Nezhdanov | Lobachevsky State University of Nizhni Novgorod (original) (raw)
Papers by Aleksey Nezhdanov
Journal of Crystal Growth
We have found that growth of the {101} faces of a KDP (KH 2 PO 4) crystal is suppressed, and the ... more We have found that growth of the {101} faces of a KDP (KH 2 PO 4) crystal is suppressed, and the growth rate of the {100} faces passes through the maximum with increasing addition of KMnO 4 to a solution with pH ¼ 4.7. We have concluded that the [MnH 2 PO 4 ] 2 þ complex and MnO 2 particles affect the growth kinetics. The X-ray and electronic paramagnetic resonance data show that manganese is incorporated into the crystal in the form of Mn 3 þ and Mn 4 þ. The local excess of a positive charge in the area with incorporated [MnH 2 PO 4 ] 2 þ complex can be compensated by the shift of the hydrogen atoms in the KDP structure.
Physics of the Solid State, 2021
Journal of Physics: Conference Series, 2021
Synthesis and modification of gallium oxide as a wide-bandgap semiconductor is a topical task in ... more Synthesis and modification of gallium oxide as a wide-bandgap semiconductor is a topical task in the fields of power electronics, UV detectors, gas sensors, telecommunication. In the present work, the Ga2O3 films deposited on sapphire substrates by magnetron sputtering have been studied. The influence of deposition parameters and subsequent annealing on the structure and optical properties of the synthesized films is analyzed. Ion doping of magnetron-deposited films with silicon is carried out by the ion implantation method. It is shown by the Raman scattering and optical transmission spectroscopy that ion irradiation leads to the disordering of the crystal structure, but subsequent annealing results in a partial recovery of the structure. Hall-effect measurements for irradiated and then annealed films do not reveal the formation of a conducting layer. Apparently, this is due to the fact that the main contribution to the resistance is made by grain boundaries in the magnetron-deposi...
Surfaces and Interfaces, 2021
2017 19th International Conference on Transparent Optical Networks (ICTON), 2017
First time arsenic sulfide nanoclusters were prepared by plasma-enhanced chemical vapor depositio... more First time arsenic sulfide nanoclusters were prepared by plasma-enhanced chemical vapor deposition. The samples were synthesized via direct interaction of arsenic and sulfur vapors into low-temperature non-equilibrium RF (40 MHz) plasma discharge at reduced pressure. The synthesized nanoclusters were precipitated one a soluble sodium chloride substrate. The dependence of properties of nanoclusters on conditions of preparation was studied.
Semiconductors, 2019
The results on the formation of locally strained Ge microstructures on silicon-on-insulator (SOI)... more The results on the formation of locally strained Ge microstructures on silicon-on-insulator (SOI) substrates and investigation of their optical properties are presented. Suspended Ge structures are formed by optical lithography and plasmachemical and selective chemical etching using the "stress concentration" approach. To provide a heat sink from Ge microstructures, their formation scheme is modified so as to provide the mechanical contact of a part of the suspended microstructure with lower-lying layers. To implement this scheme, SOI substrates with a thin upper Si layer 100 nm in thickness are used. It is shown using the measurements of Raman spectra depending on the pumping power that local heating in such structures decreases. Measurements of the microphotoluminescence spectra show a considerable increase in the signal intensity from strained regions of Ge microstructures as well as the possibility of increasing the maximal optical pumping power (not leading to irreversible changes) for microstructures, in which the mechanical contact of the strained part with lower-lying layers is provided, when compared with suspended structures.
Russian Journal of Applied Chemistry, 2016
Chalcogenide glasses of the AsS system were first obtained by melting of solid products of intera... more Chalcogenide glasses of the AsS system were first obtained by melting of solid products of interaction between As and S in low-temperature argon plasma. The plasma-chemical synthesis was performed at a reactor wall temperature not exceeding 250°C. The content of S in the AsS glasses is 54 to 72 mol %. The elemental, phase, and impurity composition of the glasses and their glass-transition point and optical properties were studied.
Journal of Physics: Conference Series, 2015
The structure and composition of a subsurface silicon layer subjected to a dual implantation of G... more The structure and composition of a subsurface silicon layer subjected to a dual implantation of Ga and N ions with subsequent annealing have been investigated using X-ray photoelectron spectroscopy, electron spin resonance, X-ray diffraction, Raman microscopy, transmission electron microscopy. The results indicate a possibility of ion-beam synthesis of GaN composite nanostructures in silicon-based materials.
Bulletin of the Russian Academy of Sciences: Physics, 2012
ABSTRACT The structural, optical, and galvanomagnetic properties of (Ga, Mn)Sb layers grown by th... more ABSTRACT The structural, optical, and galvanomagnetic properties of (Ga, Mn)Sb layers grown by the laser sputtering of solid targets in H2 flow are n studied. It is shown that at a growth temperature of 400°C, (Ga, Mn)Sb layers are single-crystal up to high Mn concentrations. The magnetic field dependence of the Hall resistance at measuring temperatures of 10–300 K contains a hysteresis loop; i. e., the layers are ferromagnetic semiconductors.
The Journal of Chemical Thermodynamics, 2014
ABSTRACT The isobaric heat capacity of monocrystalline Ca2GeO4 (olivine structure) has been measu... more ABSTRACT The isobaric heat capacity of monocrystalline Ca2GeO4 (olivine structure) has been measured between T = (6 and 350) K by precision adiabatic vacuum calorimetry for the first time. The experimental results have been used to calculate the standard (р o = 0.1 MPa) thermodynamic functions Cp,mo/R , Δ6THmo/RT , Δ6TSmo/R and Φmo/R = Δ6TSmo/R − Δ6THmo/RT (where R is the universal gas constant) of Ca2GeO4 (cr) over the range from T = (6 to 350) K. The thermal expansion coefficient (α) of this synthetic mineral has been determined from low-temperature X-ray measurements over the range from T = (100 to 300) K. Isochoric heat capacity Сv,m/R has been calculated using this low-temperature X-ray measurements and available compressibility data. The «acoustical» and «optical» components of the isochoric heat capacity have been estimated. The «optical» component of the one are calculated from the vibrational frequencies (ν) as measured by Raman spectroscopy with different polarization at room temperature and at 1 bar.
Solid State Phenomena, 2012
ABSTRACT t is reported about fabrication by laser deposition in a gaseous environment of epitaxia... more ABSTRACT t is reported about fabrication by laser deposition in a gaseous environment of epitaxial layers of ferromagnetic semiconductors GaMnSb and InMnSb. Investigations of x-ray diffraction and Raman scattering showed reasonably good crystal quality of GaMnSb and InMnSb layers. Magnetic properties were investigated by magneto-optical transversal Kerr effect and Hall effect. It is established, that GaMnSb layers are ferromagnetic at room temperature. In contrast, InMnSb samples demonstrate the ferromagnetic properties only at low temperatures (< 70 K).
Russian Journal of Applied Chemistry, 2008
Polymer films with a dispersed liquid crystal were prepared by photopolymerization of (meth)acryl... more Polymer films with a dispersed liquid crystal were prepared by photopolymerization of (meth)acrylic monomers. The electrooptical properties of these films were studied. The influence exerted by the composition of the monomer mixture, cross-linking agents, and chain-transfer agent on the liquid crystal drop size and on the transmission of the polymer-liquid crystal films was examined.
Physics of the Solid State, 2012
A comprehensive comparative study of SiO 2 and Al 2 O 3 oxide layers with Si nanocrystals formed ... more A comprehensive comparative study of SiO 2 and Al 2 O 3 oxide layers with Si nanocrystals formed by Si + ion implantation and high temperature annealing has been performed. Information on morphology, phase composition, structure, and luminescent properties of ensembles of ion synthesized silicon nanocrys tals has been obtained using confocal Raman microscopy, X ray diffraction, Fourier transform infrared spec troscopy, electron paramagnetic resonance, and photoluminescence. It has been found that the peculiarities of the formation of nanocrystals, the distribution of nanocrystals over the depth of the implanted layer, the structure, and the character of chemical bonds are similar for both types of oxide matrices; however, the pho toluminescence in the wavelength range 600-1000 nm, which is caused by the nanocrystals in the Al 2 O 3 matrix, has been observed only in the case of the formation of SiO 2 shells around the Si nanocrystals. The surface oxidation of the Si nanocrystals, which is necessary for the formation of SiO 2 shells, is possible due to the presence of excess oxygen in the Al 2 O 3 matrix (the case of Si implantation into the deposited Al 2 O 3 film), as well as due to the inflow of oxygen from the annealing atmosphere (the case of Si implantation into sap phire). In order to verify the quantum confinement mechanism of luminescence, available data on the tem perature dependence of the photoluminescence intensity have been analyzed. An analysis of the mechanisms of charge transfer and electroluminescence excitation in diode structures based on thin ion synthesized layers with silicon nanocrystals has also been performed.
Journal of Surface Investigation. X-ray, Synchrotron and Neutron Techniques, 2011
ABSTRACT The morphology, electronic structure, and optical properties of self-assembled silicon n... more ABSTRACT The morphology, electronic structure, and optical properties of self-assembled silicon nanostructures grown on the surface of highly oriented pyrolitic graphite (HOPG) by molecular beam epitaxy have been studied by ultra-high-vacuum scanning tunneling microscopy and X-ray photoemission spectroscopy in situ, as well as by Raman spectroscopy ex situ. At a coverage of less than one monolayer, formation of monolayer silicon nanoislands with an atomic structure similar to that of graphene has been observed.
2019 21st International Conference on Transparent Optical Networks (ICTON)
This work reports the analysis of near-infrared luminescence of low phonon energy (510 cm<sup&... more This work reports the analysis of near-infrared luminescence of low phonon energy (510 cm<sup>−1</sup>) fluoroindate glasses co-doped with Er<sup>3+</sup>/Tm<sup>3+</sup> and Er<sup>3+</sup>/Ho<sup>3+</sup> ions pumped by 796 nm, 980 nm laser diode, respectively. Due to donor-acceptor energy transfer and superposition of 1450 nm (Tm<sup>3+</sup>: <sup>3</sup>H<inf>4</inf> → <sup>3</sup>F<inf>4</inf>) and 1550 nm (Er<sup>3+</sup>: <sup>4</sup>I<inf>13/2</inf> → <sup>4</sup>I<inf>15/2</inf>) radiative transitions in glass co-doped with 0.1ErF<inf>3</inf>/0.3TmF<inf>3</inf> a broadband emission in the range of third telecommunication window (FWHM = 152 nm, λ<inf>exc</inf> = 796 nm) was obtained. Analysis of the spectroscopic properties of the 0.8ErF<inf>3</inf>/1.4HoF<inf>3</inf> co-doped glass showed Er<sup>3+</sup> → +R<sup>3+</sup> energy transfer and efficient sensitization of holmium ions leading to the 1.2 μm and 2 μm emission under 980 nm laser diode excitation.
Physical Chemistry Chemical Physics
Plasmon loss in Be/Si multilayer mirrors was comprehensively investigated by X-ray photoelectron ... more Plasmon loss in Be/Si multilayer mirrors was comprehensively investigated by X-ray photoelectron spectroscopy.
Nanomaterials
A new method for creating nanomaterials based on gallium oxide by ion-beam synthesis of nanocryst... more A new method for creating nanomaterials based on gallium oxide by ion-beam synthesis of nanocrystals of this compound in a SiO2/Si dielectric matrix has been proposed. The influence of the order of irradiation with ions of phase-forming elements (gallium and oxygen) on the chemical composition of implanted layers is reported. The separation of gallium profiles in the elemental and oxidized states is shown, even in the absence of post-implantation annealing. As a result of annealing, blue photoluminescence, associated with the recombination of donor–acceptor pairs (DAP) in Ga2O3 nanocrystals, appears in the spectrum. The structural characterization by transmission electron microscopy confirms the formation of β-Ga2O3 nanocrystals. The obtained results open up the possibility of using nanocrystalline gallium oxide inclusions in traditional CMOS technology.
Journal of Crystal Growth
We have found that growth of the {101} faces of a KDP (KH 2 PO 4) crystal is suppressed, and the ... more We have found that growth of the {101} faces of a KDP (KH 2 PO 4) crystal is suppressed, and the growth rate of the {100} faces passes through the maximum with increasing addition of KMnO 4 to a solution with pH ¼ 4.7. We have concluded that the [MnH 2 PO 4 ] 2 þ complex and MnO 2 particles affect the growth kinetics. The X-ray and electronic paramagnetic resonance data show that manganese is incorporated into the crystal in the form of Mn 3 þ and Mn 4 þ. The local excess of a positive charge in the area with incorporated [MnH 2 PO 4 ] 2 þ complex can be compensated by the shift of the hydrogen atoms in the KDP structure.
Physics of the Solid State, 2021
Journal of Physics: Conference Series, 2021
Synthesis and modification of gallium oxide as a wide-bandgap semiconductor is a topical task in ... more Synthesis and modification of gallium oxide as a wide-bandgap semiconductor is a topical task in the fields of power electronics, UV detectors, gas sensors, telecommunication. In the present work, the Ga2O3 films deposited on sapphire substrates by magnetron sputtering have been studied. The influence of deposition parameters and subsequent annealing on the structure and optical properties of the synthesized films is analyzed. Ion doping of magnetron-deposited films with silicon is carried out by the ion implantation method. It is shown by the Raman scattering and optical transmission spectroscopy that ion irradiation leads to the disordering of the crystal structure, but subsequent annealing results in a partial recovery of the structure. Hall-effect measurements for irradiated and then annealed films do not reveal the formation of a conducting layer. Apparently, this is due to the fact that the main contribution to the resistance is made by grain boundaries in the magnetron-deposi...
Surfaces and Interfaces, 2021
2017 19th International Conference on Transparent Optical Networks (ICTON), 2017
First time arsenic sulfide nanoclusters were prepared by plasma-enhanced chemical vapor depositio... more First time arsenic sulfide nanoclusters were prepared by plasma-enhanced chemical vapor deposition. The samples were synthesized via direct interaction of arsenic and sulfur vapors into low-temperature non-equilibrium RF (40 MHz) plasma discharge at reduced pressure. The synthesized nanoclusters were precipitated one a soluble sodium chloride substrate. The dependence of properties of nanoclusters on conditions of preparation was studied.
Semiconductors, 2019
The results on the formation of locally strained Ge microstructures on silicon-on-insulator (SOI)... more The results on the formation of locally strained Ge microstructures on silicon-on-insulator (SOI) substrates and investigation of their optical properties are presented. Suspended Ge structures are formed by optical lithography and plasmachemical and selective chemical etching using the "stress concentration" approach. To provide a heat sink from Ge microstructures, their formation scheme is modified so as to provide the mechanical contact of a part of the suspended microstructure with lower-lying layers. To implement this scheme, SOI substrates with a thin upper Si layer 100 nm in thickness are used. It is shown using the measurements of Raman spectra depending on the pumping power that local heating in such structures decreases. Measurements of the microphotoluminescence spectra show a considerable increase in the signal intensity from strained regions of Ge microstructures as well as the possibility of increasing the maximal optical pumping power (not leading to irreversible changes) for microstructures, in which the mechanical contact of the strained part with lower-lying layers is provided, when compared with suspended structures.
Russian Journal of Applied Chemistry, 2016
Chalcogenide glasses of the AsS system were first obtained by melting of solid products of intera... more Chalcogenide glasses of the AsS system were first obtained by melting of solid products of interaction between As and S in low-temperature argon plasma. The plasma-chemical synthesis was performed at a reactor wall temperature not exceeding 250°C. The content of S in the AsS glasses is 54 to 72 mol %. The elemental, phase, and impurity composition of the glasses and their glass-transition point and optical properties were studied.
Journal of Physics: Conference Series, 2015
The structure and composition of a subsurface silicon layer subjected to a dual implantation of G... more The structure and composition of a subsurface silicon layer subjected to a dual implantation of Ga and N ions with subsequent annealing have been investigated using X-ray photoelectron spectroscopy, electron spin resonance, X-ray diffraction, Raman microscopy, transmission electron microscopy. The results indicate a possibility of ion-beam synthesis of GaN composite nanostructures in silicon-based materials.
Bulletin of the Russian Academy of Sciences: Physics, 2012
ABSTRACT The structural, optical, and galvanomagnetic properties of (Ga, Mn)Sb layers grown by th... more ABSTRACT The structural, optical, and galvanomagnetic properties of (Ga, Mn)Sb layers grown by the laser sputtering of solid targets in H2 flow are n studied. It is shown that at a growth temperature of 400°C, (Ga, Mn)Sb layers are single-crystal up to high Mn concentrations. The magnetic field dependence of the Hall resistance at measuring temperatures of 10–300 K contains a hysteresis loop; i. e., the layers are ferromagnetic semiconductors.
The Journal of Chemical Thermodynamics, 2014
ABSTRACT The isobaric heat capacity of monocrystalline Ca2GeO4 (olivine structure) has been measu... more ABSTRACT The isobaric heat capacity of monocrystalline Ca2GeO4 (olivine structure) has been measured between T = (6 and 350) K by precision adiabatic vacuum calorimetry for the first time. The experimental results have been used to calculate the standard (р o = 0.1 MPa) thermodynamic functions Cp,mo/R , Δ6THmo/RT , Δ6TSmo/R and Φmo/R = Δ6TSmo/R − Δ6THmo/RT (where R is the universal gas constant) of Ca2GeO4 (cr) over the range from T = (6 to 350) K. The thermal expansion coefficient (α) of this synthetic mineral has been determined from low-temperature X-ray measurements over the range from T = (100 to 300) K. Isochoric heat capacity Сv,m/R has been calculated using this low-temperature X-ray measurements and available compressibility data. The «acoustical» and «optical» components of the isochoric heat capacity have been estimated. The «optical» component of the one are calculated from the vibrational frequencies (ν) as measured by Raman spectroscopy with different polarization at room temperature and at 1 bar.
Solid State Phenomena, 2012
ABSTRACT t is reported about fabrication by laser deposition in a gaseous environment of epitaxia... more ABSTRACT t is reported about fabrication by laser deposition in a gaseous environment of epitaxial layers of ferromagnetic semiconductors GaMnSb and InMnSb. Investigations of x-ray diffraction and Raman scattering showed reasonably good crystal quality of GaMnSb and InMnSb layers. Magnetic properties were investigated by magneto-optical transversal Kerr effect and Hall effect. It is established, that GaMnSb layers are ferromagnetic at room temperature. In contrast, InMnSb samples demonstrate the ferromagnetic properties only at low temperatures (< 70 K).
Russian Journal of Applied Chemistry, 2008
Polymer films with a dispersed liquid crystal were prepared by photopolymerization of (meth)acryl... more Polymer films with a dispersed liquid crystal were prepared by photopolymerization of (meth)acrylic monomers. The electrooptical properties of these films were studied. The influence exerted by the composition of the monomer mixture, cross-linking agents, and chain-transfer agent on the liquid crystal drop size and on the transmission of the polymer-liquid crystal films was examined.
Physics of the Solid State, 2012
A comprehensive comparative study of SiO 2 and Al 2 O 3 oxide layers with Si nanocrystals formed ... more A comprehensive comparative study of SiO 2 and Al 2 O 3 oxide layers with Si nanocrystals formed by Si + ion implantation and high temperature annealing has been performed. Information on morphology, phase composition, structure, and luminescent properties of ensembles of ion synthesized silicon nanocrys tals has been obtained using confocal Raman microscopy, X ray diffraction, Fourier transform infrared spec troscopy, electron paramagnetic resonance, and photoluminescence. It has been found that the peculiarities of the formation of nanocrystals, the distribution of nanocrystals over the depth of the implanted layer, the structure, and the character of chemical bonds are similar for both types of oxide matrices; however, the pho toluminescence in the wavelength range 600-1000 nm, which is caused by the nanocrystals in the Al 2 O 3 matrix, has been observed only in the case of the formation of SiO 2 shells around the Si nanocrystals. The surface oxidation of the Si nanocrystals, which is necessary for the formation of SiO 2 shells, is possible due to the presence of excess oxygen in the Al 2 O 3 matrix (the case of Si implantation into the deposited Al 2 O 3 film), as well as due to the inflow of oxygen from the annealing atmosphere (the case of Si implantation into sap phire). In order to verify the quantum confinement mechanism of luminescence, available data on the tem perature dependence of the photoluminescence intensity have been analyzed. An analysis of the mechanisms of charge transfer and electroluminescence excitation in diode structures based on thin ion synthesized layers with silicon nanocrystals has also been performed.
Journal of Surface Investigation. X-ray, Synchrotron and Neutron Techniques, 2011
ABSTRACT The morphology, electronic structure, and optical properties of self-assembled silicon n... more ABSTRACT The morphology, electronic structure, and optical properties of self-assembled silicon nanostructures grown on the surface of highly oriented pyrolitic graphite (HOPG) by molecular beam epitaxy have been studied by ultra-high-vacuum scanning tunneling microscopy and X-ray photoemission spectroscopy in situ, as well as by Raman spectroscopy ex situ. At a coverage of less than one monolayer, formation of monolayer silicon nanoislands with an atomic structure similar to that of graphene has been observed.
2019 21st International Conference on Transparent Optical Networks (ICTON)
This work reports the analysis of near-infrared luminescence of low phonon energy (510 cm<sup&... more This work reports the analysis of near-infrared luminescence of low phonon energy (510 cm<sup>−1</sup>) fluoroindate glasses co-doped with Er<sup>3+</sup>/Tm<sup>3+</sup> and Er<sup>3+</sup>/Ho<sup>3+</sup> ions pumped by 796 nm, 980 nm laser diode, respectively. Due to donor-acceptor energy transfer and superposition of 1450 nm (Tm<sup>3+</sup>: <sup>3</sup>H<inf>4</inf> → <sup>3</sup>F<inf>4</inf>) and 1550 nm (Er<sup>3+</sup>: <sup>4</sup>I<inf>13/2</inf> → <sup>4</sup>I<inf>15/2</inf>) radiative transitions in glass co-doped with 0.1ErF<inf>3</inf>/0.3TmF<inf>3</inf> a broadband emission in the range of third telecommunication window (FWHM = 152 nm, λ<inf>exc</inf> = 796 nm) was obtained. Analysis of the spectroscopic properties of the 0.8ErF<inf>3</inf>/1.4HoF<inf>3</inf> co-doped glass showed Er<sup>3+</sup> → +R<sup>3+</sup> energy transfer and efficient sensitization of holmium ions leading to the 1.2 μm and 2 μm emission under 980 nm laser diode excitation.
Physical Chemistry Chemical Physics
Plasmon loss in Be/Si multilayer mirrors was comprehensively investigated by X-ray photoelectron ... more Plasmon loss in Be/Si multilayer mirrors was comprehensively investigated by X-ray photoelectron spectroscopy.
Nanomaterials
A new method for creating nanomaterials based on gallium oxide by ion-beam synthesis of nanocryst... more A new method for creating nanomaterials based on gallium oxide by ion-beam synthesis of nanocrystals of this compound in a SiO2/Si dielectric matrix has been proposed. The influence of the order of irradiation with ions of phase-forming elements (gallium and oxygen) on the chemical composition of implanted layers is reported. The separation of gallium profiles in the elemental and oxidized states is shown, even in the absence of post-implantation annealing. As a result of annealing, blue photoluminescence, associated with the recombination of donor–acceptor pairs (DAP) in Ga2O3 nanocrystals, appears in the spectrum. The structural characterization by transmission electron microscopy confirms the formation of β-Ga2O3 nanocrystals. The obtained results open up the possibility of using nanocrystalline gallium oxide inclusions in traditional CMOS technology.