Pub Date : 2024-07-04DOI: 10.3897/j.moem.10.2.124089
F. Fedulov, D. V. Savelev, Y. Fetisov
Nowadays, one of the promising ways for the development of computing systems with high performance and low energy consumption is the creation of artificial synaptic devices that imitate the functions of biological synapses. Such devices have a significant potential for effectively solving problems of pattern recognition, classification, control, and the treatment of diseases of the nervous system. The work demonstrates the imitation of synaptic behavior in a composite multiferroic heterostructure based on the piezoceramics of lead zirconate titanate (PZT) and the amorphous magnetic alloy Metglas. The characteristics of the heterostructure were measured by resonant excitation of the magnetoelectric (ME) effect and applying electric field pulses of various amplitudes and polarities. The ME coefficient αE was considered as a synaptic weight, and the output electrical voltage of the heterostructure as a postsynaptic potential. The study demonstrates the possibility of simulating long-term potentiation (LTP) and depression (LTD) in the ME heterostructure, as well as spike-timing-dependent plasticity (STDP). This work shows promise for creating neuromorphic computing systems based on multiferroic composite heterostructures.
如今，开发高性能、低能耗计算系统的一个有前途的方法是制造模仿生物突触功能的人工突触设备。这种装置在有效解决模式识别、分类、控制和治疗神经系统疾病等问题方面具有巨大潜力。该研究成果展示了一种基于锆钛酸铅（PZT）压电陶瓷和非晶磁性合金 Metglas 的复合多铁性异质结构的突触行为模仿。通过共振激发磁电（ME）效应并施加不同振幅和极性的电场脉冲，测量了异质结构的特性。ME 系数 αE 被视为突触权重，而异质结构的输出电压则被视为突触后电位。这项研究证明了在 ME 异质结构中模拟长期电位（LTP）和抑制（LTD）以及尖峰计时可塑性（STDP）的可能性。这项工作为基于多铁氧体复合异质结构创建神经形态计算系统带来了希望。
{"title":"Synaptic behavior of a composite multiferroic heterostructure FeBSiC – PZT at resonant excitation","authors":"F. Fedulov, D. V. Savelev, Y. Fetisov","doi":"10.3897/j.moem.10.2.124089","DOIUrl":"https://doi.org/10.3897/j.moem.10.2.124089","url":null,"abstract":"Nowadays, one of the promising ways for the development of computing systems with high performance and low energy consumption is the creation of artificial synaptic devices that imitate the functions of biological synapses. Such devices have a significant potential for effectively solving problems of pattern recognition, classification, control, and the treatment of diseases of the nervous system. The work demonstrates the imitation of synaptic behavior in a composite multiferroic heterostructure based on the piezoceramics of lead zirconate titanate (PZT) and the amorphous magnetic alloy Metglas. The characteristics of the heterostructure were measured by resonant excitation of the magnetoelectric (ME) effect and applying electric field pulses of various amplitudes and polarities. The ME coefficient αE was considered as a synaptic weight, and the output electrical voltage of the heterostructure as a postsynaptic potential. The study demonstrates the possibility of simulating long-term potentiation (LTP) and depression (LTD) in the ME heterostructure, as well as spike-timing-dependent plasticity (STDP). This work shows promise for creating neuromorphic computing systems based on multiferroic composite heterostructures.","PeriodicalId":18610,"journal":{"name":"Modern Electronic Materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141677314","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 : 2024-07-02DOI: 10.3897/j.moem.10.2.129762
Vladimir M. Kravchenko, V. Malyutina-Bronskaya, H. S. Kuzmitskaya, Anton V. Nestsiaronak
This paper presents the results of obtaining and studying the electrical and optical characteristics of an optically transparent highly conductive Ni/Cu/Ti/ITO contact in order to reduce electrical resistance losses on the front side of the silicon solar cell. The topology of the contact metallization is a square 50 × 50 mm2 with an interdigitated electrode structure. A Ni/Cu/Ti contact metallization formed on ITO layer reduces the surface resistance by more than 60 times. It has been shown that the use of a Ni/Cu/Ti contact with a finger thickness of at least 1.5 μm and a width of 17 μm was formed is a good alternative to traditional contacts for silicon solar cells based on silver paste.
{"title":"Optically transparent highly conductive contact based on ITO and copper metallization for solar cells","authors":"Vladimir M. Kravchenko, V. Malyutina-Bronskaya, H. S. Kuzmitskaya, Anton V. Nestsiaronak","doi":"10.3897/j.moem.10.2.129762","DOIUrl":"https://doi.org/10.3897/j.moem.10.2.129762","url":null,"abstract":"This paper presents the results of obtaining and studying the electrical and optical characteristics of an optically transparent highly conductive Ni/Cu/Ti/ITO contact in order to reduce electrical resistance losses on the front side of the silicon solar cell. The topology of the contact metallization is a square 50 × 50 mm2 with an interdigitated electrode structure. A Ni/Cu/Ti contact metallization formed on ITO layer reduces the surface resistance by more than 60 times. It has been shown that the use of a Ni/Cu/Ti contact with a finger thickness of at least 1.5 μm and a width of 17 μm was formed is a good alternative to traditional contacts for silicon solar cells based on silver paste.","PeriodicalId":18610,"journal":{"name":"Modern Electronic Materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141684399","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 : 2023-12-12DOI: 10.3897/j.moem.9.4.116552
A. A. Temirov, I. Kubasov, A. Turutin, T. Ilina, A. Kislyuk, Dmitry A. Kiselev, E. A. Skryleva, Nikolai A. Sobolev, I. A. Salimon, Nikolai V. Batrameev, M. D. Malinkovich, Yuri N. Parkhomenko
Silicon-carbon films are of great interest as diamond-like materials combining unique properties, e.g. high hardness, adhesion to a wide range of materials, abrasion resistance, chemical resistance, low friction coefficient and biocompatibility. The presence of silicon in the films significantly reduces their inner mechanical stress as compared to diamond films. Currently, the films are used in industry, primarily, as solid lubricants and protective coatings. There are a large number of silicon-carbon film synthesis methods the most widely used of which are various options of chemical vapor deposition. A new silicon-carbon film synthesis technique has been suggested and tested. The technique is based on the use of high-frequency induction for obtaining plasma of silicon and carbon vapors supplied to the reaction chamber from an external source. Impurity-free silicon-carbon films containing 63–65 % carbon atoms with sp3 orbital hybridization have been synthesized on Sitall substrates. The composition, surface roughness and friction coefficient of the impurity-free silicon-carbon films synthesized using the suggested technology have been studied. The possibility of implementing resistive switching in thin silicon-carbon films in cross-bar structures with metallic electrodes has been analyzed.
{"title":"Synthesis of silicon-carbon films by induction-assisted plasma-chemical deposition","authors":"A. A. Temirov, I. Kubasov, A. Turutin, T. Ilina, A. Kislyuk, Dmitry A. Kiselev, E. A. Skryleva, Nikolai A. Sobolev, I. A. Salimon, Nikolai V. Batrameev, M. D. Malinkovich, Yuri N. Parkhomenko","doi":"10.3897/j.moem.9.4.116552","DOIUrl":"https://doi.org/10.3897/j.moem.9.4.116552","url":null,"abstract":"Silicon-carbon films are of great interest as diamond-like materials combining unique properties, e.g. high hardness, adhesion to a wide range of materials, abrasion resistance, chemical resistance, low friction coefficient and biocompatibility. The presence of silicon in the films significantly reduces their inner mechanical stress as compared to diamond films. Currently, the films are used in industry, primarily, as solid lubricants and protective coatings. There are a large number of silicon-carbon film synthesis methods the most widely used of which are various options of chemical vapor deposition. A new silicon-carbon film synthesis technique has been suggested and tested. The technique is based on the use of high-frequency induction for obtaining plasma of silicon and carbon vapors supplied to the reaction chamber from an external source. Impurity-free silicon-carbon films containing 63–65 % carbon atoms with sp3 orbital hybridization have been synthesized on Sitall substrates. The composition, surface roughness and friction coefficient of the impurity-free silicon-carbon films synthesized using the suggested technology have been studied. The possibility of implementing resistive switching in thin silicon-carbon films in cross-bar structures with metallic electrodes has been analyzed.","PeriodicalId":18610,"journal":{"name":"Modern Electronic Materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139009701","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 : 2023-12-12DOI: 10.3897/j.moem.9.4.116646
A. Kislyuk, I. Kubasov, A. A. Temirov, A. Turutin, A. Shportenko, Viktor V. Kuts, M. D. Malinkovich
Charged domain walls (CDWs) in ferroelectric materials raise both fundamental and practical interest due to their electrophysical properties differing from bulk ones. On a microstructure level, CDWs in ferroelectrics are 2D defects separating regions with different spontaneous polarization vector directions. Screening of electric field of the CDW's bound ionic charges by mobile carriers leads to the formation of elongated narrow channels with an elevated conductivity in initially dielectric materials. Controlling the position and inclination angle of CDW relative to the spontaneous polarization direction, one can change its conductivity over a wide range thus providing good opportunities for developing memory devices, including neuromorphic systems. This review describes the state of art in the formation and application of CDWs in single crystal uniaxial ferroelectric lithium niobate (LiNbO3, LN), as resistive and memristive switching devices. The main CDWs formation methods in single crystal and thin-film LN have been described, and modern data have been presented on the electrophysical properties and electrical conductivity control methods of CDWs. Prospects of CDWs application in resistive and memristive switching memory devices have been discussed.
{"title":"Electrophysical properties, memristive and resistive switching of charged domain walls in lithium niobate","authors":"A. Kislyuk, I. Kubasov, A. A. Temirov, A. Turutin, A. Shportenko, Viktor V. Kuts, M. D. Malinkovich","doi":"10.3897/j.moem.9.4.116646","DOIUrl":"https://doi.org/10.3897/j.moem.9.4.116646","url":null,"abstract":"Charged domain walls (CDWs) in ferroelectric materials raise both fundamental and practical interest due to their electrophysical properties differing from bulk ones. On a microstructure level, CDWs in ferroelectrics are 2D defects separating regions with different spontaneous polarization vector directions. Screening of electric field of the CDW's bound ionic charges by mobile carriers leads to the formation of elongated narrow channels with an elevated conductivity in initially dielectric materials. Controlling the position and inclination angle of CDW relative to the spontaneous polarization direction, one can change its conductivity over a wide range thus providing good opportunities for developing memory devices, including neuromorphic systems. This review describes the state of art in the formation and application of CDWs in single crystal uniaxial ferroelectric lithium niobate (LiNbO3, LN), as resistive and memristive switching devices. The main CDWs formation methods in single crystal and thin-film LN have been described, and modern data have been presented on the electrophysical properties and electrical conductivity control methods of CDWs. Prospects of CDWs application in resistive and memristive switching memory devices have been discussed.","PeriodicalId":18610,"journal":{"name":"Modern Electronic Materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138977100","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 : 2023-12-12DOI: 10.3897/j.moem.9.4.115181
Michael S. Afanasiev, Dmitry A. Kiselev, A. Sivov, G. Chucheva
In this work, the membrane structures based on lead-free ferroelectric barium strontium titanate with composition Ba0.8Sr0.2TO3 (BSTO) were fabricated by a magnetron sputtering method. The formation of a single-phase Ba0.8Sr0.2TO3 with thickness of 300 nm sintered on Si substrate is confirmed by XRD analysis. It is shown that films without a silicon substrate exhibit ferroelectric and piezoelectric properties. The piezoelectric and ferroelectric behaviors of BSTO thin film without a silicon substrate were confirmed through a piezoelectric force microscopy and Kelvin probe force microscopy and measurements of the effective piezoelectric coefficients (d33 and d15). Images of the residual potential of polarized areas have been obtained on the membranes, which are stable over time despite the absence of a lower electrode. Additionally, a local of ferroelectric hysteresis loop has been observed. A combination of the structural and piezoelectric measurements reveals that it possible to create freestanding ferroelectric films based on Ba0.8Sr0.2TO3 system, establishing it as a promising candidate for high-performance electromechanical applications.
{"title":"Synthesis and piezoelectric properties of freestanding ferroelectric films based on barium strontium titanate","authors":"Michael S. Afanasiev, Dmitry A. Kiselev, A. Sivov, G. Chucheva","doi":"10.3897/j.moem.9.4.115181","DOIUrl":"https://doi.org/10.3897/j.moem.9.4.115181","url":null,"abstract":"In this work, the membrane structures based on lead-free ferroelectric barium strontium titanate with composition Ba0.8Sr0.2TO3 (BSTO) were fabricated by a magnetron sputtering method. The formation of a single-phase Ba0.8Sr0.2TO3 with thickness of 300 nm sintered on Si substrate is confirmed by XRD analysis. It is shown that films without a silicon substrate exhibit ferroelectric and piezoelectric properties. The piezoelectric and ferroelectric behaviors of BSTO thin film without a silicon substrate were confirmed through a piezoelectric force microscopy and Kelvin probe force microscopy and measurements of the effective piezoelectric coefficients (d33 and d15). Images of the residual potential of polarized areas have been obtained on the membranes, which are stable over time despite the absence of a lower electrode. Additionally, a local of ferroelectric hysteresis loop has been observed. A combination of the structural and piezoelectric measurements reveals that it possible to create freestanding ferroelectric films based on Ba0.8Sr0.2TO3 system, establishing it as a promising candidate for high-performance electromechanical applications.","PeriodicalId":18610,"journal":{"name":"Modern Electronic Materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139009008","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 : 2023-12-12DOI: 10.3897/j.moem.9.4.116620
M. Silibin, P. Sklyar, Vadim D. Zhivulko, S. I. Latushko, D. V. Zheludkevich, Dmitry V. Karpinsky
Complex transition metal oxides are distinguished for a close interrelation between their type of crystal structure and electrical and magnetic properties, thus determining their practical importance. Bismuth ferrite based solid solutions contain simultaneously both dipole electric and magnetic ordering thus expanding their potential applications as external impact sensors. The sensitivity of these compositions to external fields is largely dependent on their structural state. 0.65BiFeO3–0.35Ba1-xSrxTiO3 solid solutions (0 ≤ x ≤ 1) the compositions of which are close to the rhombohedral/cubic morphotropic phase boundary have metastable structures and are therefore promising functional materials. The crystal structure and morphology of 0.65BiFeO3–0.35Ba1-xSrxTiO3 solid solutions has been studied using X-ray diffraction, scanning electron microscopy, Raman spectroscopy and energy dispersive X-ray spectroscopy. The chemical substitution of barium ions for strontium ones has been found to reduce the magnitude of rhombohedral distortions and decrease the unit cell parameters for all the substituted compounds. Solid solutions with x ≥ 0,25 have single-phase structure and cubic unit cells, their grain size decreasing with an increase in the concentration of the substituting ions. The results of structural studies obtained using Raman spectroscopy suggest the presence of rhombohedral distortions in the structures of all the compositions studied. The results of structural studies have allowed identifying the sequence of changes in the phase state and lattice parameter of the compounds in the vicinity of the rhombohedral/cubic morphotropic phase boundary. The concentration ranges in which the compounds have single-phase and two-phase structures have been found. The concentration stability range of the polar rhombohedral phase has been corrected on the basis of the structural data obtained using local and microscopic methods.
复杂的过渡金属氧化物因其晶体结构类型与电学和磁学特性之间的密切联系而与众不同，从而决定了它们的实际重要性。以铋铁氧体为基础的固溶体同时包含偶极电性和磁性排序，从而扩大了其作为外部冲击传感器的潜在应用范围。这些成分对外部场的敏感性在很大程度上取决于它们的结构状态。0.65BiFeO3-0.35Ba1-xSrxTiO3 固溶体（0 ≤ x ≤ 1）的成分接近斜方体/立方体形态相边界，具有可迁移结构，因此是很有前途的功能材料。利用 X 射线衍射、扫描电子显微镜、拉曼光谱和能量色散 X 射线光谱研究了 0.65BiFeO3-0.35Ba1-xSrxTiO3 固溶体的晶体结构和形态。研究发现，钡离子对锶离子的化学取代降低了所有取代化合物的斜方体畸变程度，并降低了单胞参数。x ≥ 0.25 的固溶体具有单相结构和立方晶胞，其晶粒尺寸随着替代离子浓度的增加而减小。利用拉曼光谱进行的结构研究结果表明，所有研究成分的结构都存在斜方体畸变。根据结构研究的结果，可以确定化合物在斜方体/立方体形态相边界附近的相态和晶格参数的变化顺序。发现了化合物具有单相和两相结构的浓度范围。根据使用局部和微观方法获得的结构数据，修正了极性斜方体相的浓度稳定范围。
{"title":"Crystalline structure of 0.65BiFeO3–0.35Ba1-xSrxTiO3 solid solutions in the vicinity of the morphotropic phase boundary","authors":"M. Silibin, P. Sklyar, Vadim D. Zhivulko, S. I. Latushko, D. V. Zheludkevich, Dmitry V. Karpinsky","doi":"10.3897/j.moem.9.4.116620","DOIUrl":"https://doi.org/10.3897/j.moem.9.4.116620","url":null,"abstract":"Complex transition metal oxides are distinguished for a close interrelation between their type of crystal structure and electrical and magnetic properties, thus determining their practical importance. Bismuth ferrite based solid solutions contain simultaneously both dipole electric and magnetic ordering thus expanding their potential applications as external impact sensors. The sensitivity of these compositions to external fields is largely dependent on their structural state. 0.65BiFeO3–0.35Ba1-xSrxTiO3 solid solutions (0 ≤ x ≤ 1) the compositions of which are close to the rhombohedral/cubic morphotropic phase boundary have metastable structures and are therefore promising functional materials. The crystal structure and morphology of 0.65BiFeO3–0.35Ba1-xSrxTiO3 solid solutions has been studied using X-ray diffraction, scanning electron microscopy, Raman spectroscopy and energy dispersive X-ray spectroscopy. The chemical substitution of barium ions for strontium ones has been found to reduce the magnitude of rhombohedral distortions and decrease the unit cell parameters for all the substituted compounds. Solid solutions with x ≥ 0,25 have single-phase structure and cubic unit cells, their grain size decreasing with an increase in the concentration of the substituting ions. The results of structural studies obtained using Raman spectroscopy suggest the presence of rhombohedral distortions in the structures of all the compositions studied. The results of structural studies have allowed identifying the sequence of changes in the phase state and lattice parameter of the compounds in the vicinity of the rhombohedral/cubic morphotropic phase boundary. The concentration ranges in which the compounds have single-phase and two-phase structures have been found. The concentration stability range of the polar rhombohedral phase has been corrected on the basis of the structural data obtained using local and microscopic methods.","PeriodicalId":18610,"journal":{"name":"Modern Electronic Materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139008446","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 : 2023-12-12DOI: 10.3897/j.moem.9.4.116423
Mikhail G. Lavrentev, Mikhail V. Voronov, Aleksey A. Ivanov, Viktoriya P. Panchenko, N. Tabachkova, Maksim K. Tapero, Ivan Yu. Yarkov
The strength and thermoelectric properties of PbTe and Sn0.9Pb0.1Te medium-temperature polycrystalline specimens with p and n conductivity types, respectively, have been studied. The specimens have been produced using extrusion and spark plasma sintering. The strength parameters of the materials were studied using uniaxial compression at 20 to 500 °C. The structure of the materials was studied using X-ray diffraction and electron microscopy. The electrical conductivity and the Seebeck coefficient were measured simultaneously using the four-probe and differential methods. The temperature conductivity and the specific heat capacity were measured using the laser flash and differential scanning calorimetry methods. The PbTe and Sn0.9Pb0.1Te materials produced using extrusion and spark plasma sintering prove to be single-phase and have homogeneous compositions. For comparable synthesis methods, the dislocation density in the Sn0.9Pb0.1Te specimens is by an order of magnitude lower than in the PbTe ones. Study of the mechanical properties of n and p conductivity type specimens over a wide temperature range from 20 to 500 °C has shown that their deformation is plastic and has no traces of brittle fracture. For these plastic materials, the strength criterion has been accepted to be the arbitrary yield stress corresponding to the stress at a 0.2% deformation. The 20 °C yield stress of PbTe and Sn0.9Pb0.1Te is far higher for the specimens produced by extrusion. For all the test temperatures and synthesis methods the Sn0.9Pb0.1Te specimens have a higher strength than the PbTe ones. The PbTe and Sn0.9Pb0.1Te specimens produced by extrusion have better thermoelectric properties than the spark plasma sintered ones. The heat conductivity of the PbTe and Sn0.9Pb0.1Te specimens is almost the same regardless of compaction method.
研究了导电率分别为 p 和 n 的铅碲和锡 0.9Pb0.1Te 中温多晶试样的强度和热电性能。这些试样是通过挤压和火花等离子烧结工艺制成的。在 20 至 500 °C 的温度条件下，利用单轴压缩对材料的强度参数进行了研究。使用 X 射线衍射和电子显微镜研究了材料的结构。使用四探针法和差分法同时测量了电导率和塞贝克系数。温度传导性和比热容是用激光闪光法和差示扫描量热法测量的。使用挤压和火花等离子烧结法生产的铅碲和锡 0.9Pb0.1Te 材料被证明是单相的，并且具有均匀的成分。在合成方法可比的情况下，Sn0.9Pb0.1Te 试样的位错密度比 PbTe 试样低一个数量级。对 n 型和 p 型导电试样在 20 至 500 °C 宽温度范围内的机械性能研究表明，它们的变形是塑性的，没有脆性断裂的痕迹。对于这些塑性材料，强度标准被认为是任意屈服应力，相当于 0.2% 变形时的应力。对于挤压法生产的试样，碲化铋和碲化锡的 20 °C 屈服应力要高得多。在所有测试温度和合成方法下，Sn0.9Pb0.1Te 试样的强度都高于 PbTe 试样。挤压法生产的铅碲和锡 0.9Pb0.1Te 试样比火花等离子烧结法生产的试样具有更好的热电特性。无论采用哪种压制方法，铅碲和锡 0.9Pb0.1Te 试样的热传导率几乎相同。
{"title":"Mechanical properties of medium-temperature thermoelectric materials based on tin and lead tellurides","authors":"Mikhail G. Lavrentev, Mikhail V. Voronov, Aleksey A. Ivanov, Viktoriya P. Panchenko, N. Tabachkova, Maksim K. Tapero, Ivan Yu. Yarkov","doi":"10.3897/j.moem.9.4.116423","DOIUrl":"https://doi.org/10.3897/j.moem.9.4.116423","url":null,"abstract":"The strength and thermoelectric properties of PbTe and Sn0.9Pb0.1Te medium-temperature polycrystalline specimens with p and n conductivity types, respectively, have been studied. The specimens have been produced using extrusion and spark plasma sintering. The strength parameters of the materials were studied using uniaxial compression at 20 to 500 °C. The structure of the materials was studied using X-ray diffraction and electron microscopy. The electrical conductivity and the Seebeck coefficient were measured simultaneously using the four-probe and differential methods. The temperature conductivity and the specific heat capacity were measured using the laser flash and differential scanning calorimetry methods.\u0000 The PbTe and Sn0.9Pb0.1Te materials produced using extrusion and spark plasma sintering prove to be single-phase and have homogeneous compositions. For comparable synthesis methods, the dislocation density in the Sn0.9Pb0.1Te specimens is by an order of magnitude lower than in the PbTe ones.\u0000 Study of the mechanical properties of n and p conductivity type specimens over a wide temperature range from 20 to 500 °C has shown that their deformation is plastic and has no traces of brittle fracture. For these plastic materials, the strength criterion has been accepted to be the arbitrary yield stress corresponding to the stress at a 0.2% deformation. The 20 °C yield stress of PbTe and Sn0.9Pb0.1Te is far higher for the specimens produced by extrusion. For all the test temperatures and synthesis methods the Sn0.9Pb0.1Te specimens have a higher strength than the PbTe ones.\u0000 The PbTe and Sn0.9Pb0.1Te specimens produced by extrusion have better thermoelectric properties than the spark plasma sintered ones. The heat conductivity of the PbTe and Sn0.9Pb0.1Te specimens is almost the same regardless of compaction method.","PeriodicalId":18610,"journal":{"name":"Modern Electronic Materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139009301","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 : 2023-12-12DOI: 10.3897/j.moem.9.4.116107
M. Yarmolich, N. Kalanda, A. Petrov, Dmitry A. Kiselev, Nikolay A. Bosak
This paper presents investigations of phase transformations during the crystallization of Sr1.5La0.5FeMoO6-δ by the solid-phase technique from a stoichiometric mixture of oxides MoO3, La2O3 and Fe2O3 and SrCO3 and precursors Sr0.5La0.5FeO3 and SrMoO4. Using XRD and thermogravimetric analyses, the influence of synthesis modes on the chemical processes occurring during the formation of double perovskite was studied. It has been established that the synthesis of lanthanum-strontium ferromolybdate in a mixture of oxides proceeds through a number of series-parallel stages. At the initial stage of interaction, the resulting lanthanum-strontium ferromolybdate is enriched with iron and its composition changes during the reaction towards an increase in the molybdenum content. As the temperature increases, the content of double perovskite increases, and the concentration of the secondary phase SrMoO4 does not disappear to zero until the synthesis temperature, which indicates that solid-phase reactions with the formation of a solid solution Sr1.5La0.5FeMoO6-δ from oxides are difficult to occur. It was determined that to minimize the influence of intermediate reaction products it is necessary to use precursors Sr0.5La0.5FeO3 and SrMoO4. Based on the results of studying the temperature dependences of the degree of phase transformations during the crystallization of double perovskite, combined heating modes were optimized. The use of optimized synthesis modes made it possible to obtain single-phase Sr1.5La0.5FeMoO6-δ powder with the superstructural ordering (82%), the Curie temperature of 450 K and a magnetization value of 40.9 A · m2 · kg-1 at T = 77 K in a magnetic field with induction B ≥ 0.86 T.
本文介绍了通过固相技术从氧化物 MoO3、La2O3、Fe2O3 和 SrCO3 的化学计量混合物以及前驱体 Sr0.5La0.5FeO3 和 SrMoO4 结晶 Sr1.5La0.5FeMoO6-δ 过程中的相变研究。通过 XRD 和热重分析，研究了合成模式对双包晶形成过程中发生的化学过程的影响。研究证实，在氧化物混合物中合成钼酸镧锶铁的过程经历了一系列平行阶段。在相互作用的初始阶段，生成的钼酸镧锶铁富含铁，其成分在反应过程中发生变化，钼含量增加。随着温度的升高，双过氧化物的含量增加，直到合成温度，次生相 SrMoO4 的浓度才消失为零，这表明很难发生由氧化物形成固溶体 Sr1.5La0.5FeMoO6-δ 的固相反应。为了尽量减少中间反应产物的影响，有必要使用 Sr0.5La0.5FeO3 和 SrMoO4 前体。根据对双包晶结晶过程中相变程度的温度依赖性的研究结果，对组合加热模式进行了优化。通过使用优化合成模式，获得了单相 Sr1.5La0.5FeMoO6-δ 粉末，该粉末具有超结构有序性（82%），居里温度为 450 K，在磁感应强度 B ≥ 0.86 T 的磁场中，T = 77 K 时的磁化值为 40.9 A - m2 - kg-1。
{"title":"Magnetic properties of Sr1.5La0.5FeMoO6-δ depending on the phase composition of the reaction mixture","authors":"M. Yarmolich, N. Kalanda, A. Petrov, Dmitry A. Kiselev, Nikolay A. Bosak","doi":"10.3897/j.moem.9.4.116107","DOIUrl":"https://doi.org/10.3897/j.moem.9.4.116107","url":null,"abstract":"This paper presents investigations of phase transformations during the crystallization of Sr1.5La0.5FeMoO6-δ by the solid-phase technique from a stoichiometric mixture of oxides MoO3, La2O3 and Fe2O3 and SrCO3 and precursors Sr0.5La0.5FeO3 and SrMoO4. Using XRD and thermogravimetric analyses, the influence of synthesis modes on the chemical processes occurring during the formation of double perovskite was studied. It has been established that the synthesis of lanthanum-strontium ferromolybdate in a mixture of oxides proceeds through a number of series-parallel stages. At the initial stage of interaction, the resulting lanthanum-strontium ferromolybdate is enriched with iron and its composition changes during the reaction towards an increase in the molybdenum content. As the temperature increases, the content of double perovskite increases, and the concentration of the secondary phase SrMoO4 does not disappear to zero until the synthesis temperature, which indicates that solid-phase reactions with the formation of a solid solution Sr1.5La0.5FeMoO6-δ from oxides are difficult to occur. It was determined that to minimize the influence of intermediate reaction products it is necessary to use precursors Sr0.5La0.5FeO3 and SrMoO4. Based on the results of studying the temperature dependences of the degree of phase transformations during the crystallization of double perovskite, combined heating modes were optimized. The use of optimized synthesis modes made it possible to obtain single-phase Sr1.5La0.5FeMoO6-δ powder with the superstructural ordering (82%), the Curie temperature of 450 K and a magnetization value of 40.9 A · m2 · kg-1 at T = 77 K in a magnetic field with induction B ≥ 0.86 T.","PeriodicalId":18610,"journal":{"name":"Modern Electronic Materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139009354","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 : 2023-11-10DOI: 10.3390/electronicmat4040013
Masaya Ichimura
GaOOH, having a bandgap of 4.7–4.9 eV, can be regarded as one of several ultrawide-bandgap (UWBG) semiconductors, although it has so far mainly been used as a precursor material of Ga2O3. To examine the possibility of valence control and application in electronics, impurity levels in GaOOH are investigated using the first-principles density-functional theory calculation. The density values of the states of a supercell including an impurity atom are calculated. According to the results, among the group 14 elements, Si is expected to introduce a shallow donor level, i.e., a free electron is introduced. On the other hand, Ge and Sn introduce a localized state about 0.7 eV below the conduction band edge, and thus cannot act as an effective donor. While Mg and Ca can introduce a free hole and act as a shallow acceptor, Zn and Cd introduce acceptor levels away from the valence band. The transition metal elements (Fe, Co, Ni, Cu) are also considered, but none of them are expected to act as a shallow dopant. Thus, the results suggest that the carrier concentration can be controlled if Si is used for n-type doping, and Mg and Ca for p-type doping. Since GaOOH can be easily deposited using various chemical techniques at low temperatures, GaOOH will potentially be useful for transparent electronic devices.
{"title":"Theoretical Study of Doping in GaOOH for Electronics Applications","authors":"Masaya Ichimura","doi":"10.3390/electronicmat4040013","DOIUrl":"https://doi.org/10.3390/electronicmat4040013","url":null,"abstract":"GaOOH, having a bandgap of 4.7–4.9 eV, can be regarded as one of several ultrawide-bandgap (UWBG) semiconductors, although it has so far mainly been used as a precursor material of Ga2O3. To examine the possibility of valence control and application in electronics, impurity levels in GaOOH are investigated using the first-principles density-functional theory calculation. The density values of the states of a supercell including an impurity atom are calculated. According to the results, among the group 14 elements, Si is expected to introduce a shallow donor level, i.e., a free electron is introduced. On the other hand, Ge and Sn introduce a localized state about 0.7 eV below the conduction band edge, and thus cannot act as an effective donor. While Mg and Ca can introduce a free hole and act as a shallow acceptor, Zn and Cd introduce acceptor levels away from the valence band. The transition metal elements (Fe, Co, Ni, Cu) are also considered, but none of them are expected to act as a shallow dopant. Thus, the results suggest that the carrier concentration can be controlled if Si is used for n-type doping, and Mg and Ca for p-type doping. Since GaOOH can be easily deposited using various chemical techniques at low temperatures, GaOOH will potentially be useful for transparent electronic devices.","PeriodicalId":18610,"journal":{"name":"Modern Electronic Materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135186648","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 : 2023-10-12DOI: 10.3390/electronicmat4040012
Ju-Seong Kim, Jonghyun Choi, Won Kook Choi
In this work, we report the first attempt to investigate the dependence of thioacetamide (TAA) on the size of ZnO nanoparticles (NPs) in forming ZnS nanostructures from ZnO. Size-controlled B(blue)_, G(green)_, and Y(yellow)_ZnO quantum dots (QDs) and NC (nanocrystalline)_ZnO NPs were synthesized using a sol–gel process and a hydrothermal method, respectively, and then reacted with an ethanolic TAA solution as a sulfur source. ZnO QDs/NPs began to decompose into ZnS QDs through a reaction with TAA for 5~10 min, so rather than forming a composite of ZnO/ZnS, ZnO QDs and ZnS QDs were separated and remained in a mixed state. At last, ZnO QDs/NPs were completely decomposed into ZnS QDs after a reaction with TAA for 1 h irrespective of the size of ZnO QDs up to ~50 nm. All results indicate that ZnS formation is due to direct crystal growth and/or the chemical conversion of ZnO to ZnS.
{"title":"Size-Controlled ZnO Nanoparticles Synthesized with Thioacetamide and Formation of ZnS Quantum Dots","authors":"Ju-Seong Kim, Jonghyun Choi, Won Kook Choi","doi":"10.3390/electronicmat4040012","DOIUrl":"https://doi.org/10.3390/electronicmat4040012","url":null,"abstract":"In this work, we report the first attempt to investigate the dependence of thioacetamide (TAA) on the size of ZnO nanoparticles (NPs) in forming ZnS nanostructures from ZnO. Size-controlled B(blue)_, G(green)_, and Y(yellow)_ZnO quantum dots (QDs) and NC (nanocrystalline)_ZnO NPs were synthesized using a sol–gel process and a hydrothermal method, respectively, and then reacted with an ethanolic TAA solution as a sulfur source. ZnO QDs/NPs began to decompose into ZnS QDs through a reaction with TAA for 5~10 min, so rather than forming a composite of ZnO/ZnS, ZnO QDs and ZnS QDs were separated and remained in a mixed state. At last, ZnO QDs/NPs were completely decomposed into ZnS QDs after a reaction with TAA for 1 h irrespective of the size of ZnO QDs up to ~50 nm. All results indicate that ZnS formation is due to direct crystal growth and/or the chemical conversion of ZnO to ZnS.","PeriodicalId":18610,"journal":{"name":"Modern Electronic Materials","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135968366","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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