Pub Date : 2020-01-01DOI: 10.21272/jnep.12(2).02021
Nupur P. Vora, Priyank V. Kumar, S. Vyas, N. K. Bhatt, P. R. Vyas, V. Gohel
The experimental and theoretical studies of various properties of transition metals alloys are important in the material science research. Inspired by such fact, in the present communication we have carried out theoretical studies of lattice dynamics and dynamical elastic constants of Rh0.6Pd0.4 and Rh0.2Pd0.8 using transition metal pseudopotential. The form of the pseudopotential used in the present calculation is directly derived from generalized pseudopotential theory (GPT) and no phenomenology was used to construct pseudopotential in real space. The pseudopotential was found to be successful for the study of static, dynamic and transport properties of many transition metals. In absence of any experimental and theoretical studies first time we are presenting theoretical results of phonon dispersion for both the alloys which may be considered as prediction. Due to unavailability of experimental results, presently computed elastic constants are comparable with those studied recently by using Exact Muffin-Tin Orbitals method within the Perdew-Burke-Ernzerhof exchange-correlation approximation. Encouraged by present approach, we would like to extend it further for the remaining binary alloys of transition metals alloys.
{"title":"Theoretical Investigations of Lattice Dynamics and Dynamical Elastic Constants of Rh0.6Pd0.4 and Rh0.2Pd0.8 Binary Alloys Using Transition Metal Pseudopotential","authors":"Nupur P. Vora, Priyank V. Kumar, S. Vyas, N. K. Bhatt, P. R. Vyas, V. Gohel","doi":"10.21272/jnep.12(2).02021","DOIUrl":"https://doi.org/10.21272/jnep.12(2).02021","url":null,"abstract":"The experimental and theoretical studies of various properties of transition metals alloys are important in the material science research. Inspired by such fact, in the present communication we have carried out theoretical studies of lattice dynamics and dynamical elastic constants of Rh0.6Pd0.4 and Rh0.2Pd0.8 using transition metal pseudopotential. The form of the pseudopotential used in the present calculation is directly derived from generalized pseudopotential theory (GPT) and no phenomenology was used to construct pseudopotential in real space. The pseudopotential was found to be successful for the study of static, dynamic and transport properties of many transition metals. In absence of any experimental and theoretical studies first time we are presenting theoretical results of phonon dispersion for both the alloys which may be considered as prediction. Due to unavailability of experimental results, presently computed elastic constants are comparable with those studied recently by using Exact Muffin-Tin Orbitals method within the Perdew-Burke-Ernzerhof exchange-correlation approximation. Encouraged by present approach, we would like to extend it further for the remaining binary alloys of transition metals alloys.","PeriodicalId":16514,"journal":{"name":"Journal of Nano- and Electronic Physics","volume":"4 4 1","pages":"02021-1-02021-3"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90235797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.21272/jnep.12(3).03016
V. Kidalov, A. Dyadenchuk, Y. Bacherikov, I. Rogozin, V. Kidalov
It is the purpose of this work to research the formation process of zinc oxide by the method of HF magnetron sputtering on silicon substrates of orientation (100) with the previously applied system of macropores. Samples of porous silicon were obtained by electrochemical etching. n-type Si (100) wafers were used. Precipitation of thin ZnO films was carried out in an RF discharge in an argon atmosphere with oxygen by sputtering a zinc target. The target had a diameter of 80 mm and a thickness of 6 mm. The deposition time was 1200 s. The pressure in the growth chamber was maintained at a level of 10 – 3 Pa. The substrate temperature was fixed at 300 °C. X-ray examination of ZnO has shown that the films have a polycrystalline nature with a wurtzite-type structure and hexagonal phase. ZnO crystallites in the coatings are highly oriented along the c-axis and perpendicular to the substrate surface. The lattice constant along the crystallographic c-axis of ZnO film was 5.2260 Å. The average crystallite size calculated by the Selyakov-Scherrer formula was 12 nm. According to SEM, grain size was ~ 50-100 nm. These discrepancies are explained by the presence of microstrains in the atomic matrix of the sample, as well as instrumental factors. The microelement analysis revealed practically perfect stoichiometry of ZnO grown on porous-Si/Si.
{"title":"ZnO Growth on Macroporous Si Substrates by HF Magnetron Sputtering","authors":"V. Kidalov, A. Dyadenchuk, Y. Bacherikov, I. Rogozin, V. Kidalov","doi":"10.21272/jnep.12(3).03016","DOIUrl":"https://doi.org/10.21272/jnep.12(3).03016","url":null,"abstract":"It is the purpose of this work to research the formation process of zinc oxide by the method of HF magnetron sputtering on silicon substrates of orientation (100) with the previously applied system of macropores. Samples of porous silicon were obtained by electrochemical etching. n-type Si (100) wafers were used. Precipitation of thin ZnO films was carried out in an RF discharge in an argon atmosphere with oxygen by sputtering a zinc target. The target had a diameter of 80 mm and a thickness of 6 mm. The deposition time was 1200 s. The pressure in the growth chamber was maintained at a level of 10 – 3 Pa. The substrate temperature was fixed at 300 °C. X-ray examination of ZnO has shown that the films have a polycrystalline nature with a wurtzite-type structure and hexagonal phase. ZnO crystallites in the coatings are highly oriented along the c-axis and perpendicular to the substrate surface. The lattice constant along the crystallographic c-axis of ZnO film was 5.2260 Å. The average crystallite size calculated by the Selyakov-Scherrer formula was 12 nm. According to SEM, grain size was ~ 50-100 nm. These discrepancies are explained by the presence of microstrains in the atomic matrix of the sample, as well as instrumental factors. The microelement analysis revealed practically perfect stoichiometry of ZnO grown on porous-Si/Si.","PeriodicalId":16514,"journal":{"name":"Journal of Nano- and Electronic Physics","volume":"53 1","pages":"03016-1-03016-4"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90847797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.21272/jnep.12(3).03040
O. Petchenko, G. Petchenko, S. Boiko, A. Bezugly
Pulse-echo method in the frequency range 37.5-232.5 MHz has been used to study the behavior of dislocation decrement d(f) on X-ray irradiated to doses 0-600 R NaCl single crystals with the residual strain value of 0.5 % at room temperature. It has been found out that with the increasing doses of radiation, the effect of amplitude damping of the dislocation resonance can be observed, which leads to a marked restoration of initial acoustic characteristics of the crystals. It also noted that high-frequency asymptote for these theoretical profiles are identical which is characteristic only for acoustic testing of irradiated crystals. From the frequency curves, taken from crystals with different doses of radiation, the dependencies of the viscosity coefficient B and the average effective length of the dislocation segment L on the dose of irradiation have been determined in the framework of Granato-Lucke's string dislocation theory. In the framework of the Stern and Granato model, the behavior of m(), fm() and L() curves has been studied. The validity of the theoretical prognostications concerning increasing or decreasing with the exposure time according to the law (1 + t)2 parameters m, fm, and L have been proved. A good match of the calculations’ results with the theoretical curve L() by Stern-Granato and Granato-Lucke theories has been noted. Obtained results show, that the parameter B does not depend on the irradiation dose in the range 0-600 R. It confirms the validity of the views that the coefficient of dynamic damping of dislocations B is a fundamental characteristic of the crystal depending only on the interaction of dislocations with the phonon subsystem of the crystal and not depending on the parameters of its dislocation structure.
{"title":"Analysis of the Dynamic and Structural Characteristics’ Behavior in NaCl Single Crystals Pre-deformed and Х-ray Irradiated","authors":"O. Petchenko, G. Petchenko, S. Boiko, A. Bezugly","doi":"10.21272/jnep.12(3).03040","DOIUrl":"https://doi.org/10.21272/jnep.12(3).03040","url":null,"abstract":"Pulse-echo method in the frequency range 37.5-232.5 MHz has been used to study the behavior of dislocation decrement d(f) on X-ray irradiated to doses 0-600 R NaCl single crystals with the residual strain value of 0.5 % at room temperature. It has been found out that with the increasing doses of radiation, the effect of amplitude damping of the dislocation resonance can be observed, which leads to a marked restoration of initial acoustic characteristics of the crystals. It also noted that high-frequency asymptote for these theoretical profiles are identical which is characteristic only for acoustic testing of irradiated crystals. From the frequency curves, taken from crystals with different doses of radiation, the dependencies of the viscosity coefficient B and the average effective length of the dislocation segment L on the dose of irradiation have been determined in the framework of Granato-Lucke's string dislocation theory. In the framework of the Stern and Granato model, the behavior of m(), fm() and L() curves has been studied. The validity of the theoretical prognostications concerning increasing or decreasing with the exposure time according to the law (1 + t)2 parameters m, fm, and L have been proved. A good match of the calculations’ results with the theoretical curve L() by Stern-Granato and Granato-Lucke theories has been noted. Obtained results show, that the parameter B does not depend on the irradiation dose in the range 0-600 R. It confirms the validity of the views that the coefficient of dynamic damping of dislocations B is a fundamental characteristic of the crystal depending only on the interaction of dislocations with the phonon subsystem of the crystal and not depending on the parameters of its dislocation structure.","PeriodicalId":16514,"journal":{"name":"Journal of Nano- and Electronic Physics","volume":"10 1","pages":"03040-1-03040-3"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91127972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.21272/jnep.12(2).02015
S. J. Patel, A. Jariwala, C. Panchal, V. Kheraj
In this paper, we report a simple method to extract thickness and refractive index of thin-film from experimentally measured reflectivity spectra using teaching-learning based optimization (TLBO) algorithm. The algorithm finds thickness and refractive index by fitting an experimentally measured reflectivity spectra with theoretically ones generated by transfer matrix approach. The value of refractive index as a function of wavelength is determined by considering sellmeier dispersion relation. The algorithm is implemented by means of an interactive numerical simulation using LabVIEW as a programming tool. To check the effectiveness of the self-developed program, it is tested on different thin-film samples prepared from some commonly used optical materials such as MgF2, Al2O3 and SiO2 using electron beam evaporation technique. The values of thicknesses and refractive index spectra for different thin-film samples obtained by TLBO algorithm are verified using standard spectroscopic ellipsometry measurements. It is found that there is an excellent agreement between the results obtained by the TLBO algorithm and those by ellipsometry. It is also demonstrated that a simple reflectivity measurements give the valuable information about the thickness and dispersive refractive index over a range of wavelengths, which are obtained by our self-developed simulation program based on TLBO algorithm.
{"title":"Determination of Thickness and Optical Parameters of Thin Films from Reflectivity Spectra Using Teaching-Learning Based Optimization Algorithm","authors":"S. J. Patel, A. Jariwala, C. Panchal, V. Kheraj","doi":"10.21272/jnep.12(2).02015","DOIUrl":"https://doi.org/10.21272/jnep.12(2).02015","url":null,"abstract":"In this paper, we report a simple method to extract thickness and refractive index of thin-film from experimentally measured reflectivity spectra using teaching-learning based optimization (TLBO) algorithm. The algorithm finds thickness and refractive index by fitting an experimentally measured reflectivity spectra with theoretically ones generated by transfer matrix approach. The value of refractive index as a function of wavelength is determined by considering sellmeier dispersion relation. The algorithm is implemented by means of an interactive numerical simulation using LabVIEW as a programming tool. To check the effectiveness of the self-developed program, it is tested on different thin-film samples prepared from some commonly used optical materials such as MgF2, Al2O3 and SiO2 using electron beam evaporation technique. The values of thicknesses and refractive index spectra for different thin-film samples obtained by TLBO algorithm are verified using standard spectroscopic ellipsometry measurements. It is found that there is an excellent agreement between the results obtained by the TLBO algorithm and those by ellipsometry. It is also demonstrated that a simple reflectivity measurements give the valuable information about the thickness and dispersive refractive index over a range of wavelengths, which are obtained by our self-developed simulation program based on TLBO algorithm.","PeriodicalId":16514,"journal":{"name":"Journal of Nano- and Electronic Physics","volume":"46 1","pages":"02015-1-02015-6"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80737887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.21272/jnep.12(3).03030
P. Kolkovskyi, B. Rachiy, M. I. Kolkovskyi, B. Ostafiychuk, I. Yaremiy, V. Kotsyubynsky, R. V. Ilnitsky
{"title":"Synthesis and Electrochemical Properties of Mesoporous α-MnO2 for Supercapacitor Applications","authors":"P. Kolkovskyi, B. Rachiy, M. I. Kolkovskyi, B. Ostafiychuk, I. Yaremiy, V. Kotsyubynsky, R. V. Ilnitsky","doi":"10.21272/jnep.12(3).03030","DOIUrl":"https://doi.org/10.21272/jnep.12(3).03030","url":null,"abstract":"","PeriodicalId":16514,"journal":{"name":"Journal of Nano- and Electronic Physics","volume":"529 1","pages":"03030-1-03030-4"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79638889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.21272/jnep.12(5).05022
K. Bendjebbar, D. Rached, W. Rahal, S. Bahlouli
The silicon HIT (heterojunction with intrinsic thin layer) solar cell has great potential to improve photovoltaic efficiency and reduce costs because of the low temperature deposition technology of hydrogenated amorphous silicon a-Si:H combined with the high stable efficiency of crystalline silicon c-Si. To gain insight into the general functioning of the HIT solar cell, we have studied in this article the semiconductor-metal junction at the back contact of HIT p-type c-Si solar cell: (indium tin oxide (ITO)/hydrogenated n-doped amorphous silicon (n-a-Si:H)/hydrogenated intrinsic polymorphous silicon (i-pm-Si:H)/p-doped crystalline silicon (p-c-Si)/aluminum (Al)). Using computer modeling, we have found that unlike the junction on ITO/ n-a-Si:H on the front HIT solar cells which does not depend on the front contact barrier height b0, an increase in the back contact barrier height bL leads to an upward band bending in the valence band in this type of cell which eliminates the barrier for holes and makes more photogenerated holes able to pass from the active layer (p-doped crystalline silicon p-c-Si) to the metal (aluminium). The increase in the electric field by changing the surface band bending at the junction p-c-Si/Al causes an increase in VOC which leads to an increase in the solar cell efficiency from 17.21 % to 17.38 %. Choosing metal with high work function like palladium, chrome or ruthenium, could be the best choice as a back contact for this type of solar cell.
{"title":"Simulation Study of Metal-semiconductor Back Contact p-c-Si/Al on Silicon Heterojunction Solar Cells","authors":"K. Bendjebbar, D. Rached, W. Rahal, S. Bahlouli","doi":"10.21272/jnep.12(5).05022","DOIUrl":"https://doi.org/10.21272/jnep.12(5).05022","url":null,"abstract":"The silicon HIT (heterojunction with intrinsic thin layer) solar cell has great potential to improve photovoltaic efficiency and reduce costs because of the low temperature deposition technology of hydrogenated amorphous silicon a-Si:H combined with the high stable efficiency of crystalline silicon c-Si. To gain insight into the general functioning of the HIT solar cell, we have studied in this article the semiconductor-metal junction at the back contact of HIT p-type c-Si solar cell: (indium tin oxide (ITO)/hydrogenated n-doped amorphous silicon (n-a-Si:H)/hydrogenated intrinsic polymorphous silicon (i-pm-Si:H)/p-doped crystalline silicon (p-c-Si)/aluminum (Al)). Using computer modeling, we have found that unlike the junction on ITO/ n-a-Si:H on the front HIT solar cells which does not depend on the front contact barrier height b0, an increase in the back contact barrier height bL leads to an upward band bending in the valence band in this type of cell which eliminates the barrier for holes and makes more photogenerated holes able to pass from the active layer (p-doped crystalline silicon p-c-Si) to the metal (aluminium). The increase in the electric field by changing the surface band bending at the junction p-c-Si/Al causes an increase in VOC which leads to an increase in the solar cell efficiency from 17.21 % to 17.38 %. Choosing metal with high work function like palladium, chrome or ruthenium, could be the best choice as a back contact for this type of solar cell.","PeriodicalId":16514,"journal":{"name":"Journal of Nano- and Electronic Physics","volume":"78 4 1","pages":"05022-1-05022-4"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79643765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.21272/jnep.12(5).05010
T. Ghaitaoui, A. Benatillah
1 Department of Material Sciences, Institute of Science and Technology, University of Ahmed Draia, Adrar, Algeria 2 Laboratory of Energy, Environment and Systems of Information (LEESI), University of Ahmed Draia, Adrar, Algeria 3 Laboratoire de Développement Durable et d'information (LDDI), Faculté des Science et de la Technologie, Université Ahmed Draia, Adrar, Algéria 4 Unité de Recherche en Energies Renouvelables en Milieu Saharien, URERMS, Centre de Développement des Energies Renouvelables, CDER, 01000 Adrar, Algéria
1 Department of Material Sciences Institute of Science and Technology)、Ahmed Draia大学2、Adrar angoisse Laboratory of Energy, Environment and Systems of Information (Ahmed Draia LEESI)、大学、实验室(Adrar阿尔及利亚3 (LDDI)、可持续发展和信息科学与技术学院、大学、Ahmed Draia Adrar Algéria 4单元研究撒哈拉,URERMS环境中可再生能源、可再生能源发展中心。CDER, 01000阿德拉，阿尔及利亚
{"title":"Analysis and Evaluation of Climatic Conditions Effect on Amorphous Silicon PV Module","authors":"T. Ghaitaoui, A. Benatillah","doi":"10.21272/jnep.12(5).05010","DOIUrl":"https://doi.org/10.21272/jnep.12(5).05010","url":null,"abstract":"1 Department of Material Sciences, Institute of Science and Technology, University of Ahmed Draia, Adrar, Algeria 2 Laboratory of Energy, Environment and Systems of Information (LEESI), University of Ahmed Draia, Adrar, Algeria 3 Laboratoire de Développement Durable et d'information (LDDI), Faculté des Science et de la Technologie, Université Ahmed Draia, Adrar, Algéria 4 Unité de Recherche en Energies Renouvelables en Milieu Saharien, URERMS, Centre de Développement des Energies Renouvelables, CDER, 01000 Adrar, Algéria","PeriodicalId":16514,"journal":{"name":"Journal of Nano- and Electronic Physics","volume":"136 1","pages":"05010-1-05010-5"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77353206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.21272/jnep.12(3).03022
R. Kolodka, Akademik Glushkov Prosp. Kyiv Ukraine, I. Pundyk, I. Dmitruk
{"title":"Study of Coherent Properties of an Exciton in Semiconductor Quantum Dots","authors":"R. Kolodka, Akademik Glushkov Prosp. Kyiv Ukraine, I. Pundyk, I. Dmitruk","doi":"10.21272/jnep.12(3).03022","DOIUrl":"https://doi.org/10.21272/jnep.12(3).03022","url":null,"abstract":"","PeriodicalId":16514,"journal":{"name":"Journal of Nano- and Electronic Physics","volume":"45 5 1","pages":"03022-1-03022-6"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77473325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.21272/jnep.12(5).05032
M. Karimov, U. Kutliev, K. Otabaeva, M. U. Otabaev
{"title":"Angular Distributions of Scattered Ne and Ar Ions at the Grazing Incidence on the InGaP (001) 110 Surface","authors":"M. Karimov, U. Kutliev, K. Otabaeva, M. U. Otabaev","doi":"10.21272/jnep.12(5).05032","DOIUrl":"https://doi.org/10.21272/jnep.12(5).05032","url":null,"abstract":"","PeriodicalId":16514,"journal":{"name":"Journal of Nano- and Electronic Physics","volume":"73 1","pages":"05032-1-05032-4"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73347539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.21272/jnep.12(3).03008
F. Ptashchenko
Based on quantum-chemical calculations by the density functional theory (DFT) method, four possible mechanisms of the influence of ammonia vapors on the conductivity of silicon nanostructures, in particular, porous silicon (PS), were examined. The first mechanism involves the emergence of donor states in the interaction of NH3 molecules with pb-centers (surface Si atoms with dangling bonds). The change in conductivity by the second and third mechanisms can occur in p-type silicon structures. The second mechanism involves the protonation of an ammonia molecule with the subsequent passivation of subsurface impurity boron atoms by NH4 ions. The third mechanism combines the first two. At the first stage, it involves the interaction of NH3 molecules with passivated B-pb-center pairs. After protonation of the NH3 molecule, the boron impurity atom is already passivated by the NH4 ion, and the paramagnetic state of the pb-center is restored. At the second stage, the formation of donor states occurs during the interaction of NH3 molecules with already paramagnetic pb-centers. The processes according to the fourth mechanism can occur in n-type silicon structures. It provides for the restoration of donor properties of surface phosphorus atoms passivated by two hydrogen atoms. Such a restoration occurs after protonation of the NH3 molecule, when the proton (the ion of the surface hydrogen atom) is separated from the phosphorus atom. The last three models involve the protonation of NH3 molecules with the necessary participation of water molecules and surface OHgroups, the important role of which has been demonstrated in most experimental studies.
{"title":"Mechanisms of Changing the Conductivity of Porous Silicon in an Ammonia Atmosphere – DFT Modeling","authors":"F. Ptashchenko","doi":"10.21272/jnep.12(3).03008","DOIUrl":"https://doi.org/10.21272/jnep.12(3).03008","url":null,"abstract":"Based on quantum-chemical calculations by the density functional theory (DFT) method, four possible mechanisms of the influence of ammonia vapors on the conductivity of silicon nanostructures, in particular, porous silicon (PS), were examined. The first mechanism involves the emergence of donor states in the interaction of NH3 molecules with pb-centers (surface Si atoms with dangling bonds). The change in conductivity by the second and third mechanisms can occur in p-type silicon structures. The second mechanism involves the protonation of an ammonia molecule with the subsequent passivation of subsurface impurity boron atoms by NH4 ions. The third mechanism combines the first two. At the first stage, it involves the interaction of NH3 molecules with passivated B-pb-center pairs. After protonation of the NH3 molecule, the boron impurity atom is already passivated by the NH4 ion, and the paramagnetic state of the pb-center is restored. At the second stage, the formation of donor states occurs during the interaction of NH3 molecules with already paramagnetic pb-centers. The processes according to the fourth mechanism can occur in n-type silicon structures. It provides for the restoration of donor properties of surface phosphorus atoms passivated by two hydrogen atoms. Such a restoration occurs after protonation of the NH3 molecule, when the proton (the ion of the surface hydrogen atom) is separated from the phosphorus atom. The last three models involve the protonation of NH3 molecules with the necessary participation of water molecules and surface OHgroups, the important role of which has been demonstrated in most experimental studies.","PeriodicalId":16514,"journal":{"name":"Journal of Nano- and Electronic Physics","volume":"114 1","pages":"03008-1-03008-7"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73296070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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