Pub Date : 2021-04-12DOI: 10.3952/PHYSICS.V61I1.4405
J. M. Cuvas-Limón, J. G. Ortega-Mendoza, J. Padilla-Martínez, P. Zaca-Morán
In this work, the study of two-photon absorption by gold nanoparticles of different diameters photodeposited onto the core of a single-mode optical fibre is presented. The photodeposition of nanoparticles with diameters of 10, 20, 50 and 100 nm was achieved using a continuous wave laser at a wavelength of 1550 nm and a power of 50 mW. Nonlinear optical characterization was carried out by using the P-scan technique of a high gain erbium doped fibre amplifier with pulses of 20 ns at a frequency of 10 kHz, that provides a maximum intensity of approximately 60 MW/cm2. The results show that for gold nanoparticles greater than 20 nm photodeposited onto the fibre, in both cases, the nonlinear coefficient as well as the third-order susceptibility increase as the diameter of the nanoparticles increases, describing a typical behaviour of the two-photon absorption. The obtained results can be used for the design of filters and optical limiters in the communications area.
{"title":"Measurement of two-photon absorption by gold nanoparticles of different sizes photodeposited onto the core of an optical fibre","authors":"J. M. Cuvas-Limón, J. G. Ortega-Mendoza, J. Padilla-Martínez, P. Zaca-Morán","doi":"10.3952/PHYSICS.V61I1.4405","DOIUrl":"https://doi.org/10.3952/PHYSICS.V61I1.4405","url":null,"abstract":"In this work, the study of two-photon absorption by gold nanoparticles of different diameters photodeposited onto the core of a single-mode optical fibre is presented. The photodeposition of nanoparticles with diameters of 10, 20, 50 and 100 nm was achieved using a continuous wave laser at a wavelength of 1550 nm and a power of 50 mW. Nonlinear optical characterization was carried out by using the P-scan technique of a high gain erbium doped fibre amplifier with pulses of 20 ns at a frequency of 10 kHz, that provides a maximum intensity of approximately 60 MW/cm2. The results show that for gold nanoparticles greater than 20 nm photodeposited onto the fibre, in both cases, the nonlinear coefficient as well as the third-order susceptibility increase as the diameter of the nanoparticles increases, describing a typical behaviour of the two-photon absorption. The obtained results can be used for the design of filters and optical limiters in the communications area.","PeriodicalId":18144,"journal":{"name":"Lithuanian Journal of Physics","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46974833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-12DOI: 10.3952/PHYSICS.V61I1.4406
D. V. Khveshchenko
This note discusses the attempts of fitting a number of the approximate power-law dependencies observed in the cuprates into one consistent holographic or holographically inspired hydrodynamic framework. Contrary to the expectations, the goal of reproducing as many as possible of the established behaviors of the thermodynamic and transport coefficients appears to be achievable within the simplistic picture of a non-degenerate fermion fluid with quadratic dispersion. While not immediately elucidating the essential physics of the cuprates, this observation suggests a possible reason for which the previous attempts towards that goal have remained inconclusive.
{"title":"Die hard holographic phenomenology of cuprates","authors":"D. V. Khveshchenko","doi":"10.3952/PHYSICS.V61I1.4406","DOIUrl":"https://doi.org/10.3952/PHYSICS.V61I1.4406","url":null,"abstract":"This note discusses the attempts of fitting a number of the approximate power-law dependencies observed in the cuprates into one consistent holographic or holographically inspired hydrodynamic framework. Contrary to the expectations, the goal of reproducing as many as possible of the established behaviors of the thermodynamic and transport coefficients appears to be achievable within the simplistic picture of a non-degenerate fermion fluid with quadratic dispersion. While not immediately elucidating the essential physics of the cuprates, this observation suggests a possible reason for which the previous attempts towards that goal have remained inconclusive.","PeriodicalId":18144,"journal":{"name":"Lithuanian Journal of Physics","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45541240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-12DOI: 10.3952/PHYSICS.V61I1.4403
B. K. Barik, H. M. Mallya, Rajeev Kumar Sinha, S. Chidangil
In this work, experimental and theoretical studies on danthron and emodin are presented. Experimentally, Fourier transform infrared (FTIR), Raman and UV–Vis spectra of danthron and emodin were recorded. The structure and vibrational frequencies of the molecules were calculated using density functional theory (DFT) with the B3LYP functional using the triple zeta (TZVP) basis set. Among various possible structures of danthron and emodin, it was found that the most stable structures involve intramolecular hydrogen bonds between two OH and C=O groups. The theoretical IR spectra of the most stable conformations of danthron and emodin correlate well with their experimental FTIR. Detailed vibrational frequency analysis was done for all the vibrational modes obtained and were assigned to the ring vibrations along with the stretching and bending of specific bond vibrations. The bands obtained from the experimental FTIR and Raman spectra of both the molecules correlate well with their theoretical data.
{"title":"Molecular structure and spectra of danthron and emodin studied by FTIR, Raman spectroscopy and DFT techniques","authors":"B. K. Barik, H. M. Mallya, Rajeev Kumar Sinha, S. Chidangil","doi":"10.3952/PHYSICS.V61I1.4403","DOIUrl":"https://doi.org/10.3952/PHYSICS.V61I1.4403","url":null,"abstract":"In this work, experimental and theoretical studies on danthron and emodin are presented. Experimentally, Fourier transform infrared (FTIR), Raman and UV–Vis spectra of danthron and emodin were recorded. The structure and vibrational frequencies of the molecules were calculated using density functional theory (DFT) with the B3LYP functional using the triple zeta (TZVP) basis set. Among various possible structures of danthron and emodin, it was found that the most stable structures involve intramolecular hydrogen bonds between two OH and C=O groups. The theoretical IR spectra of the most stable conformations of danthron and emodin correlate well with their experimental FTIR. Detailed vibrational frequency analysis was done for all the vibrational modes obtained and were assigned to the ring vibrations along with the stretching and bending of specific bond vibrations. The bands obtained from the experimental FTIR and Raman spectra of both the molecules correlate well with their theoretical data.","PeriodicalId":18144,"journal":{"name":"Lithuanian Journal of Physics","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47081334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-12DOI: 10.3952/PHYSICS.V61I1.4404
V. Klimavičius, F. Kuliesius, E. Orentas, V. Balevičius
The 1H → 31P cross-polarization (CP) kinetics in the nanostructured calcium hydroxyapatite (nanoCaHA) was measured under moderate (5 kHz) magic-angle spinning (MAS) rate. This material was chosen as it contains the distanced 1H–31P spin pairs and the interactions between them are characterized by a relatively low dipolar coupling (b) that could be comparable with the spin-diffusion rates (R). Therefore, the physical legitimacy to use the secular solution of the quantum Liouville–von Neumann equation is doubtful. The semi-nonsecular model of spin dynamics was applied, and the results were compared with those obtained by the secular approach. The comparable results obtained by both models show that the secular model is applicable, with certain reservation, also in the case of |b| ≈ R. The extremely high anisotropy of spin diffusion in the nano-CaHA was deduced. This can be a matter of the applied approach, as the interactions of the 31P spins with the proton bath were neglected in both models. The high anisotropy could also be caused by the physical reasons that stem from the structural and proton diffusion features of CaHA. This material belongs to low-dimensional proton conductors possessing a large motional freedom for protons along OH– chains.
{"title":"Secular and semi-nonsecular models of cross-polarization kinetics for remote spins: an application for nano-structured calcium hydroxyapatite","authors":"V. Klimavičius, F. Kuliesius, E. Orentas, V. Balevičius","doi":"10.3952/PHYSICS.V61I1.4404","DOIUrl":"https://doi.org/10.3952/PHYSICS.V61I1.4404","url":null,"abstract":"The 1H → 31P cross-polarization (CP) kinetics in the nanostructured calcium hydroxyapatite (nanoCaHA) was measured under moderate (5 kHz) magic-angle spinning (MAS) rate. This material was chosen as it contains the distanced 1H–31P spin pairs and the interactions between them are characterized by a relatively low dipolar coupling (b) that could be comparable with the spin-diffusion rates (R). Therefore, the physical legitimacy to use the secular solution of the quantum Liouville–von Neumann equation is doubtful. The semi-nonsecular model of spin dynamics was applied, and the results were compared with those obtained by the secular approach. The comparable results obtained by both models show that the secular model is applicable, with certain reservation, also in the case of |b| ≈ R. The extremely high anisotropy of spin diffusion in the nano-CaHA was deduced. This can be a matter of the applied approach, as the interactions of the 31P spins with the proton bath were neglected in both models. The high anisotropy could also be caused by the physical reasons that stem from the structural and proton diffusion features of CaHA. This material belongs to low-dimensional proton conductors possessing a large motional freedom for protons along OH– chains.","PeriodicalId":18144,"journal":{"name":"Lithuanian Journal of Physics","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41852511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-12DOI: 10.3952/PHYSICS.V61I1.4407
R. Mokrik, V. Samalavičius, M. Gregorauskas, M. Bujanauskas
In this study, modelled groundwater actual flow times in intermediate and deep aquifers, covered by regional scale impermeable aquitards, were compared with 4He and 81Kr age dating results. To improve the reliability of the steady state 3D groundwater flow model, the isotopic ages of deep groundwater were compared to the MODPATH modelled travel times. The highest helium values in groundwater reservoirs coincide with fault zones in the crystalline basement and sedimentary cover near Rapakivi granite massifs. Insights into isotope-geochemical anomalies of the Baltic Artesian Basin intermediate and deep groundwater support their main distribution peculiarities in the flow path towards the Baltic Sea coast lowland and seabed depression as the regional groundwater discharge area.
{"title":"Environmental isotopes and noble gas ages of the deep groundwater with coupled flow modelling in the Baltic artesian basin","authors":"R. Mokrik, V. Samalavičius, M. Gregorauskas, M. Bujanauskas","doi":"10.3952/PHYSICS.V61I1.4407","DOIUrl":"https://doi.org/10.3952/PHYSICS.V61I1.4407","url":null,"abstract":"In this study, modelled groundwater actual flow times in intermediate and deep aquifers, covered by regional scale impermeable aquitards, were compared with 4He and 81Kr age dating results. To improve the reliability of the steady state 3D groundwater flow model, the isotopic ages of deep groundwater were compared to the MODPATH modelled travel times. The highest helium values in groundwater reservoirs coincide with fault zones in the crystalline basement and sedimentary cover near Rapakivi granite massifs. Insights into isotope-geochemical anomalies of the Baltic Artesian Basin intermediate and deep groundwater support their main distribution peculiarities in the flow path towards the Baltic Sea coast lowland and seabed depression as the regional groundwater discharge area.","PeriodicalId":18144,"journal":{"name":"Lithuanian Journal of Physics","volume":"61 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41838477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-02DOI: 10.3952/physics.v61i4.4642
D. Khveshchenko
Keywords: phase space, holographic correspondence, hydrodynamics, effective metric We discuss the Wigner function representation from the novel standpoint of establishing a natural holographylike correspondence between the descriptions of a generic quantum system in the phase space (‘bulk’) picture versus its spacetime (‘boundary’) counterpart. In certain cases, the former may reduce to the gravity-like dynamics of a local metric-type variable while the latter takes on the form of some bosonized collective field hydrodynamics. This generic pseudo-holographic duality neither relies on any particular symmetry of the system in question, nor does it require any relation to some underlying ‘string theory’, thus providing a systematic way of constructing practical – as opposed to the previous ‘ad hoc’ – examples of genuine holographic duality.
{"title":"Phase space holography with no strings attached","authors":"D. Khveshchenko","doi":"10.3952/physics.v61i4.4642","DOIUrl":"https://doi.org/10.3952/physics.v61i4.4642","url":null,"abstract":"Keywords: phase space, holographic correspondence, hydrodynamics, effective metric \u0000We discuss the Wigner function representation from the novel standpoint of establishing a natural holographylike correspondence between the descriptions of a generic quantum system in the phase space (‘bulk’) picture versus its spacetime (‘boundary’) counterpart. In certain cases, the former may reduce to the gravity-like dynamics of a local metric-type variable while the latter takes on the form of some bosonized collective field hydrodynamics. This generic pseudo-holographic duality neither relies on any particular symmetry of the system in question, nor does it require any relation to some underlying ‘string theory’, thus providing a systematic way of constructing practical – as opposed to the previous ‘ad hoc’ – examples of genuine holographic duality.","PeriodicalId":18144,"journal":{"name":"Lithuanian Journal of Physics","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47913342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-18DOI: 10.21203/rs.3.rs-142975/v1
M. Mačernis, L. Mourokh, L. Valkunas
Photoinduced proton pumping in bateriorhodopsin (bR) was extensively studied using multiple experimental methods and utilizing various theoretical modeling approaches. These studies usually refer to well-resolved structural data of bacteriorhodopsin. However, despite obtained results, the origin of the proton pumping force initiated by the electronic excitation of retinal remains questionable. Here we discuss the challenges and approaches to modeling the proton transfer in bR and demonstrate that the process, which starts from the electronic excitation of the retinal molecule, is mainly due to the detailed arrangement of the protein environment. Using quantum chemical calculations, we have revealed that the retinal molecule after its excitation is fixed in the ground state of 13-cis,15-syn configuration, as a result of interaction with specific protein residuals. Thus, reaching this fixed configuration, the proton is first transferred to the Asp-85 residue from the water molecule, which is subsequently restored by the proton initially located in the Schiff base.
{"title":"Mechanism of Proton Transfer in Bacteriorhodopsin","authors":"M. Mačernis, L. Mourokh, L. Valkunas","doi":"10.21203/rs.3.rs-142975/v1","DOIUrl":"https://doi.org/10.21203/rs.3.rs-142975/v1","url":null,"abstract":"Photoinduced proton pumping in bateriorhodopsin (bR) was extensively studied using multiple experimental methods and utilizing various theoretical modeling approaches. These studies usually refer to well-resolved structural data of bacteriorhodopsin. However, despite obtained results, the origin of the proton pumping force initiated by the electronic excitation of retinal remains questionable. Here we discuss the challenges and approaches to modeling the proton transfer in bR and demonstrate that the process, which starts from the electronic excitation of the retinal molecule, is mainly due to the detailed arrangement of the protein environment. Using quantum chemical calculations, we have revealed that the retinal molecule after its excitation is fixed in the ground state of 13-cis,15-syn configuration, as a result of interaction with specific protein residuals. Thus, reaching this fixed configuration, the proton is first transferred to the Asp-85 residue from the water molecule, which is subsequently restored by the proton initially located in the Schiff base.","PeriodicalId":18144,"journal":{"name":"Lithuanian Journal of Physics","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47350514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.3952/physics.v61i3.4514
K. Shunkeyev, Z. Ubaev, A. Lushchik, L. Myasnikova
The processes of radiation defect creation and radiative relaxation of electronic excitations under applied local or/and uniaxial elastic deformation have been studied in NaCl crystals by means of optical absorption, luminescence and thermoactivation spectroscopy methods. In NaCl:Li at 80 K, X-ray-induced absorption bands peaked around 3.35 and 4.6 eV have been detected and ascribed to interstitial halide atoms located nearby Li impurity cations, HA(Li) centres. Subsequent thermal annealing of HA(Li) centres leads to the formation of polyhalide centres responsible for the absorption band at 5.35 eV. In an X-irradiated and stressed NaCl:Li crystal (degree of uniaxial elastic deformation of ε = 0.9%), the peak of thermally stimulated luminescence at ~115 K is composed of the ~2.7-eV emission appearing, in our opinion, due to the recombination of the electron, thermally released from an F′ centre, with a hole-type HA(Li) centre. The applied uniaxial elastic stress facilitates the self-trapping of anion excitons in regular regions of a NaCl lattice and impedes the energy transfer by mobile excitons to impurities/defects and, in turn, attenuates the Br-related luminescence peaked at 3.95 eV with respect to the π-emission of self-trapped excitons (~3.35 eV). The 3.95 eV emission has been detected in a natural NaCl crystal containing homologous Br impurity ions.
{"title":"Radiation defects in NaCl matrix with reduced lattice symmetry caused by light cation doping and elastic uniaxial deformation","authors":"K. Shunkeyev, Z. Ubaev, A. Lushchik, L. Myasnikova","doi":"10.3952/physics.v61i3.4514","DOIUrl":"https://doi.org/10.3952/physics.v61i3.4514","url":null,"abstract":"The processes of radiation defect creation and radiative relaxation of electronic excitations under applied local or/and uniaxial elastic deformation have been studied in NaCl crystals by means of optical absorption, luminescence and thermoactivation spectroscopy methods. In NaCl:Li at 80 K, X-ray-induced absorption bands peaked around 3.35 and 4.6 eV have been detected and ascribed to interstitial halide atoms located nearby Li impurity cations, HA(Li) centres. Subsequent thermal annealing of HA(Li) centres leads to the formation of polyhalide centres responsible for the absorption band at 5.35 eV. In an X-irradiated and stressed NaCl:Li crystal (degree of uniaxial elastic deformation of ε = 0.9%), the peak of thermally stimulated luminescence at ~115 K is composed of the ~2.7-eV emission appearing, in our opinion, due to the recombination of the electron, thermally released from an F′ centre, with a hole-type HA(Li) centre. The applied uniaxial elastic stress facilitates the self-trapping of anion excitons in regular regions of a NaCl lattice and impedes the energy transfer by mobile excitons to impurities/defects and, in turn, attenuates the Br-related luminescence peaked at 3.95 eV with respect to the π-emission of self-trapped excitons (~3.35 eV). The 3.95 eV emission has been detected in a natural NaCl crystal containing homologous Br impurity ions.","PeriodicalId":18144,"journal":{"name":"Lithuanian Journal of Physics","volume":"1 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70032346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.3952/physics.v61i3.4515
D. Kulmatova, M. Baitimirova, U. Malinovskis, C. Chang, Y. Gu, A. Tamulevičienė, D. Erts, J. Prikulis
We examine the influence of colloidal Au and Ag nanoparticles (NP) on hydrothermally grown ZnO nanorods (NR). Individual 60 nm diameter NP and small NP assemblies without formation of large aggregates were deposited on poly-L-lysine covered NR films using the dip-coating method. The evaluation of morphological and optical properties of the obtained ZnO-metal hybrids was done using scanning electron microscopy, photoluminescence (PL) and diffuse reflection spectroscopy. The presence of Au NP selectively suppressed the PL components near 560 nm wavelength associated with ZnO surface defects, whereas equally sized Ag NP resulted in a much smaller change of PL signal, barely above the noise level. The presented results may be useful for tuning the optical properties of hybrid materials in development of sensor or photovoltaic devices.
{"title":"Deposition of colloidal metal nanoparticles on zinc oxide nanorods and their influence on visible photoluminescence","authors":"D. Kulmatova, M. Baitimirova, U. Malinovskis, C. Chang, Y. Gu, A. Tamulevičienė, D. Erts, J. Prikulis","doi":"10.3952/physics.v61i3.4515","DOIUrl":"https://doi.org/10.3952/physics.v61i3.4515","url":null,"abstract":"We examine the influence of colloidal Au and Ag nanoparticles (NP) on hydrothermally grown ZnO nanorods (NR). Individual 60 nm diameter NP and small NP assemblies without formation of large aggregates were deposited on poly-L-lysine covered NR films using the dip-coating method. The evaluation of morphological and optical properties of the obtained ZnO-metal hybrids was done using scanning electron microscopy, photoluminescence (PL) and diffuse reflection spectroscopy. The presence of Au NP selectively suppressed the PL components near 560 nm wavelength associated with ZnO surface defects, whereas equally sized Ag NP resulted in a much smaller change of PL signal, barely above the noise level. The presented results may be useful for tuning the optical properties of hybrid materials in development of sensor or photovoltaic devices.","PeriodicalId":18144,"journal":{"name":"Lithuanian Journal of Physics","volume":"1 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70032411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.3952/physics.v61i3.4517
K. Surovovs, A. Kravtsov, J. Virbulis
The pedestal method is an alternative to the well-known floating zone method, both of which are performed with high-frequency electromagnetic heating. Unlike the floating zone method, in the pedestal method a single crystal is pulled upwards from the melt. It allows one to lower feed rod quality requirements and simplify the process control due to the absence of open melting front. As the pedestal method has not been widely used in industry for silicon crystals, its development requires extensive numerical modelling. The present work describes application of the previously created mathematical model for crystals with diameters higher than it is currently possible in the experimental setup, as well as for the cone growth phase. Supplementary free surface heating, that prevents melt centre freezing during the seeding phase, has been added at the beginning of cone phase. After multiple sets of simulations, an optimal scheme of heating control for cone growth was proposed.
{"title":"Modelling of the pedestal growth of silicon crystals","authors":"K. Surovovs, A. Kravtsov, J. Virbulis","doi":"10.3952/physics.v61i3.4517","DOIUrl":"https://doi.org/10.3952/physics.v61i3.4517","url":null,"abstract":"The pedestal method is an alternative to the well-known floating zone method, both of which are performed with high-frequency electromagnetic heating. Unlike the floating zone method, in the pedestal method a single crystal is pulled upwards from the melt. It allows one to lower feed rod quality requirements and simplify the process control due to the absence of open melting front. As the pedestal method has not been widely used in industry for silicon crystals, its development requires extensive numerical modelling. The present work describes application of the previously created mathematical model for crystals with diameters higher than it is currently possible in the experimental setup, as well as for the cone growth phase. Supplementary free surface heating, that prevents melt centre freezing during the seeding phase, has been added at the beginning of cone phase. After multiple sets of simulations, an optimal scheme of heating control for cone growth was proposed.","PeriodicalId":18144,"journal":{"name":"Lithuanian Journal of Physics","volume":"1 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70032463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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