Pub Date : 2025-02-01DOI: 10.1016/j.omx.2024.100389
M.P. Plokker, H.T. Hintzen
The positioning of the Tm2+ 4f125d1 and 4f13 energy levels as relative to the conduction band of the orthorhombic BaCl2 host lattice has been determined. Therefore, the energies of the Tm2+ 4f125d1-and excited 4f13-level were retrieved, as relative to the Tm2+ 4f13 ground state. In addition, the energy for exciton creation in the orthorhombic BaCl2 host lattice was established, from which the bandgap energy was determined. This value was found to correspond quite well to known literature values. Furthermore, the Tm3+-Cl- charge transfer transition was determined, from which the energy difference between the Tm2+ 4f13 ground state and the top of the BaCl2 valence band was deduced. A host referred binding energy scheme deduced for BaCl2:Tm2+ then showed that the lowest energy Tm2+ 4f125d1-levels are positioned 0.3–0.5 eV below the BaCl2 conduction band. Room temperature photo-excitation into this level will then most likely result in thermal ionization effects that have an impact on the Tm2+ 4f125d1→4f13 and 4f13→4f13 luminescence and corresponding quantum yield.
{"title":"The influence of the conduction band of BaCl2 on the thermal quenching of the Tm2+ 4f125d1→4f13 and 4f13→4f13 luminescence in orthorhombic BaCl2:Tm2+/3+","authors":"M.P. Plokker, H.T. Hintzen","doi":"10.1016/j.omx.2024.100389","DOIUrl":"10.1016/j.omx.2024.100389","url":null,"abstract":"<div><div>The positioning of the Tm<sup>2+</sup> 4f<sup>12</sup>5d<sup>1</sup> and 4f<sup>13</sup> energy levels as relative to the conduction band of the orthorhombic BaCl<sub>2</sub> host lattice has been determined. Therefore, the energies of the Tm<sup>2+</sup> 4f<sup>12</sup>5d<sup>1</sup>-and excited 4f<sup>13</sup>-level were retrieved, as relative to the Tm<sup>2+</sup> 4f<sup>13</sup> ground state. In addition, the energy for exciton creation in the orthorhombic BaCl<sub>2</sub> host lattice was established, from which the bandgap energy was determined. This value was found to correspond quite well to known literature values. Furthermore, the Tm<sup>3+</sup>-Cl<sup>-</sup> charge transfer transition was determined, from which the energy difference between the Tm<sup>2+</sup> 4f<sup>13</sup> ground state and the top of the BaCl<sub>2</sub> valence band was deduced. A host referred binding energy scheme deduced for BaCl<sub>2</sub>:Tm<sup>2+</sup> then showed that the lowest energy Tm<sup>2+</sup> 4f<sup>12</sup>5d<sup>1</sup>-levels are positioned 0.3–0.5 eV below the BaCl<sub>2</sub> conduction band. Room temperature photo-excitation into this level will then most likely result in thermal ionization effects that have an impact on the Tm<sup>2+</sup> 4f<sup>12</sup>5d<sup>1</sup>→4f<sup>13</sup> and 4f<sup>13</sup>→4f<sup>13</sup> luminescence and corresponding quantum yield.</div></div>","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"25 ","pages":"Article 100389"},"PeriodicalIF":0.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.omx.2025.100399
Zhanymgul Koishybayeva , Fedor Konusov , Sergey Pavlov , Dmitrii Sidelev , Artur Nassyrbayev , Ruslan Gadyrov , Vladislav Tarbokov , Elena Polisadova , Abdirash Akilbekov
In this work the effect of an intense pulsed ion irradiation with a high flux ∼1020 cm−2s−1 on structure, optical and photo-electrical properties of gallium oxide thin films have been investigated. The films were produced by the radio-frequency magnetron sputtering method and had amorphous structure. A part of deposited films was annealed in the air environment (900 °C, 1 h) for synthesis of β-Ga2O3 phase. Obtained films were subjected to the intense pulsed ion irradiation (ion energy - up to 200 keV, pulse duration - 100 ns, current density on the target - up to 30 A/cm2, number of pulses - 3). The influence of irradiation on optical absorption and photoluminescence spectra, field and temperature dependencies of dark and photoconductivity were investigated. The probable nature of growth defects is discussed, and a scheme of electronic transitions that determine optical properties is proposed.
{"title":"Modification of optical and photoelectrical properties of thin gallium oxide films by intense pulsed 200 keV C+ ion beams","authors":"Zhanymgul Koishybayeva , Fedor Konusov , Sergey Pavlov , Dmitrii Sidelev , Artur Nassyrbayev , Ruslan Gadyrov , Vladislav Tarbokov , Elena Polisadova , Abdirash Akilbekov","doi":"10.1016/j.omx.2025.100399","DOIUrl":"10.1016/j.omx.2025.100399","url":null,"abstract":"<div><div>In this work the effect of an intense pulsed ion irradiation with a high flux ∼10<sup>20</sup> cm<sup>−2</sup>s<sup>−1</sup> on structure, optical and photo-electrical properties of gallium oxide thin films have been investigated. The films were produced by the radio-frequency magnetron sputtering method and had amorphous structure. A part of deposited films was annealed in the air environment (900 °C, 1 h) for synthesis of β-Ga<sub>2</sub>O<sub>3</sub> phase. Obtained films were subjected to the intense pulsed ion irradiation (ion energy - up to 200 keV, pulse duration - 100 ns, current density on the target - up to 30 A/cm<sup>2</sup>, number of pulses - 3). The influence of irradiation on optical absorption and photoluminescence spectra, field and temperature dependencies of dark and photoconductivity were investigated. The probable nature of growth defects is discussed, and a scheme of electronic transitions that determine optical properties is proposed.</div></div>","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"25 ","pages":"Article 100399"},"PeriodicalIF":0.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143182673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Preface to the special issue after ESTE 2023 conference","authors":"Dariusz Hreniak , Mariusz Stefański , Wiesław Stręk , Rober Tomala , Eugeniusz Zych","doi":"10.1016/j.omx.2024.100379","DOIUrl":"10.1016/j.omx.2024.100379","url":null,"abstract":"","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"24 ","pages":"Article 100379"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143180467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-23DOI: 10.1016/j.omx.2024.100381
A. Trukhin
Treatment of copper-doped natural α-quartz in oxygen atmosphere at 1200 °C leads to changes in luminescence properties. The luminescence center of AlO4−-Cu+ is modified. The intensity is low in the annealed sample and increases after X-ray irradiation at 293 K. Annealing of the irradiated sample leads to a strong peak of thermally stimulated luminescence (TSL) at ∼500 K. Its spectral composition is mainly due to the AlO4−-Cu+ center. Irradiation of the sample treated with oxygen at 77 K gives a new TSL peak at ∼180 K and a peak at 244 K existing in the untreated sample. Both peaks were attributed to Cuo centers released from different sites and recombined with a hole in AlO4 having additional oxygen. The introduction of copper ions into quartz removes alkali metal ions and eliminates the corresponding luminescence, but after treatment in oxygen, luminescence with similar parameters is restored at low temperatures. In this case, only the glow of the AlO4−-Cu+ center is observed in the recombination luminescence (TSL and afterglow). Therefore, modification of the AlO4−-Cu + center with oxygen imparts to this center properties similar to the complex center AlO4− (K, Na or Li ion) with monovalent aluminum ions, although the alkali ions are replaced by copper ions. The oxygen-treated sample exhibits an increased efficiency of energy transfer by excitons to the luminescence center, measured as excitation spectra in the region of fundamental absorption of silicon dioxide. The X-ray excitation of the self-trapped exciton luminescence does not depend on oxygen treatment. Also, the spectra of intrinsic optical reflection and Raman scattering do not change compared to the untreated sample. The obtained result is interpreted as a modification of the defect by high-temperature treatment in oxygen.
在 1200 °C 氧气环境中处理掺铜天然 α-石英会导致发光特性发生变化。AlO4-Cu+ 的发光中心发生了变化。退火样品的发光强度较低，而在 293 K 的 X 射线辐照下，发光强度会增加。辐照样品退火后，在 ∼500 K 处会出现一个强烈的热激发发光（TSL）峰。在 77 K 下用氧气辐照处理过的样品，会在 ∼180 K 处出现一个新的 TSL 峰，而未经处理的样品则会在 244 K 处出现一个峰。这两个峰都是由于 Cuo 中心从不同位置释放出来，并与 AlO4 中含有额外氧的空穴重新结合。在石英中引入铜离子会移除碱金属离子并消除相应的发光，但在氧气中处理后，低温下会恢复具有类似参数的发光。在这种情况下，在重组发光（TSL 和余辉）中只能观察到 AlO4-Cu+ 中心的辉光。因此，氧对 AlO4-Cu+ 中心的修饰赋予了该中心类似于带有单价铝离子的复合中心 AlO4-（K、Na 或 Li 离子）的特性，尽管碱离子被铜离子取代了。经过氧处理的样品显示，激子向发光中心转移能量的效率有所提高。自俘获激子发光的 X 射线激发与氧处理无关。此外，与未处理的样品相比，本征光学反射和拉曼散射的光谱也没有变化。这一结果被解释为在氧气中进行高温处理后，缺陷发生了改变。
{"title":"Luminescence of copper-doped α-quartz crystal after oxygen treatment","authors":"A. Trukhin","doi":"10.1016/j.omx.2024.100381","DOIUrl":"10.1016/j.omx.2024.100381","url":null,"abstract":"<div><div>Treatment of copper-doped natural α-quartz in oxygen atmosphere at 1200 °C leads to changes in luminescence properties. The luminescence center of AlO<sub>4</sub><sup>−</sup>-Cu<sup>+</sup> is modified. The intensity is low in the annealed sample and increases after X-ray irradiation at 293 K. Annealing of the irradiated sample leads to a strong peak of thermally stimulated luminescence (TSL) at ∼500 K. Its spectral composition is mainly due to the AlO<sub>4</sub><sup>−</sup>-Cu<sup>+</sup> center. Irradiation of the sample treated with oxygen at 77 K gives a new TSL peak at ∼180 K and a peak at 244 K existing in the untreated sample. Both peaks were attributed to Cu<sup>o</sup> centers released from different sites and recombined with a hole in AlO<sub>4</sub> having additional oxygen. The introduction of copper ions into quartz removes alkali metal ions and eliminates the corresponding luminescence, but after treatment in oxygen, luminescence with similar parameters is restored at low temperatures. In this case, only the glow of the AlO<sub>4</sub><sup>−</sup>-Cu<sup>+</sup> center is observed in the recombination luminescence (TSL and afterglow). Therefore, modification of the AlO<sub>4</sub><sup>−</sup>-Cu <sup>+</sup> center with oxygen imparts to this center properties similar to the complex center AlO<sub>4</sub><sup>−</sup> (K, Na or Li ion) with monovalent aluminum ions, although the alkali ions are replaced by copper ions. The oxygen-treated sample exhibits an increased efficiency of energy transfer by excitons to the luminescence center, measured as excitation spectra in the region of fundamental absorption of silicon dioxide. The X-ray excitation of the self-trapped exciton luminescence does not depend on oxygen treatment. Also, the spectra of intrinsic optical reflection and Raman scattering do not change compared to the untreated sample. The obtained result is interpreted as a modification of the defect by high-temperature treatment in oxygen.</div></div>","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"25 ","pages":"Article 100381"},"PeriodicalIF":0.0,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142720223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-23DOI: 10.1016/j.omx.2024.100383
Kymbat M. Tynyshbayeva , Artem L. Kozlovskiy
The paper presents the results of the influence of heavy ion irradiation on the formation of anisotropic distortions of the crystal structure and electron density distribution in SiC ceramics. The assessment of the change in the properties of the damaged layer was carried out using Raman spectroscopy methods, and using data on structural changes obtained using the X-ray diffraction method. The observed alterations in the spectral modes E1(TO), E2(TO) and A1(LO) depending on the irradiation temperature indicate an anisotropic distortion of the structure, which has a clearly expressed dependence on the irradiation temperature, as well as the type of ions used for irradiation. The assessment results of changes in the electron density distribution contingent upon the irradiation temperature for both types of ion irradiation showed a direct correlation between the irradiation temperature growth and the electron density anisotropic distortion caused by the deformation of chemical bonds. In turn, the combination of the effects of thermal heating and ionization processes causes deformation distortion of chemical bonds, which is most pronounced at high irradiation temperatures, for which thermal expansion of the crystal lattice and accelerated diffusion of vacancy defects play a key role in disordering.
本文介绍了重离子辐照对碳化硅陶瓷晶体结构和电子密度分布形成各向异性畸变的影响结果。利用拉曼光谱方法和 X 射线衍射方法获得的结构变化数据，对受损层的性质变化进行了评估。观察到的光谱模式 E1(TO)、E2(TO) 和 A1(LO)的变化取决于辐照温度，这表明结构发生了各向异性的畸变，这种畸变与辐照温度以及辐照所用离子的类型有明显的关系。对两种离子辐照的电子密度分布随辐照温度变化的评估结果表明，辐照温度增长与化学键变形导致的电子密度各向异性畸变之间存在直接关联。反过来，热加热和电离过程的综合效应也会导致化学键的变形畸变，这种畸变在高辐照温度下最为明显，因为晶格的热膨胀和空位缺陷的加速扩散在无序化过程中起着关键作用。
{"title":"The effect of temperature factor during heavy ion irradiation on structural disordering of SiC ceramics","authors":"Kymbat M. Tynyshbayeva , Artem L. Kozlovskiy","doi":"10.1016/j.omx.2024.100383","DOIUrl":"10.1016/j.omx.2024.100383","url":null,"abstract":"<div><div>The paper presents the results of the influence of heavy ion irradiation on the formation of anisotropic distortions of the crystal structure and electron density distribution in SiC ceramics. The assessment of the change in the properties of the damaged layer was carried out using Raman spectroscopy methods, and using data on structural changes obtained using the X-ray diffraction method. The observed alterations in the spectral modes E<sub>1</sub>(TO), E<sub>2</sub>(TO) and A<sub>1</sub>(LO) depending on the irradiation temperature indicate an anisotropic distortion of the structure, which has a clearly expressed dependence on the irradiation temperature, as well as the type of ions used for irradiation. The assessment results of changes in the electron density distribution contingent upon the irradiation temperature for both types of ion irradiation showed a direct correlation between the irradiation temperature growth and the electron density anisotropic distortion caused by the deformation of chemical bonds. In turn, the combination of the effects of thermal heating and ionization processes causes deformation distortion of chemical bonds, which is most pronounced at high irradiation temperatures, for which thermal expansion of the crystal lattice and accelerated diffusion of vacancy defects play a key role in disordering.</div></div>","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"25 ","pages":"Article 100383"},"PeriodicalIF":0.0,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142720222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-21DOI: 10.1016/j.omx.2024.100380
Hasan Yilmaz , Masahiko Isobe , Oliver Clemens , Markus Suta , Pascal Puphal
The advancement of synthesis of materials with luminescence properties of lanthanoid ions in various single crystalline host compounds with low phonon energies has facilitated the optimization of numerous materials to meet the specific optical properties required for diverse applications such as new energy resource exploration, light-emitting diodes (LEDs), quantum dot displays, laser technology, sensors, telecommunications, medical diagnostics and more. Enhanced analyses of the luminescence mechanism of lanthanoid ions in various host compounds, which have captivated researchers for many years and culminated in the development of innovative materials for optical applications. To obtain a deeper understanding of the luminescence mechanism of Sm3+, Eu3+, and Ho3+ ions incorporated into the Ruddlesden-Popper-type host compounds (La1-xREx)SrGaO4 (RE = Sm, Eu, Ho and x = 0; 0.05; 0.10) high quality single crystals with homogenous activator distribution grown by the optical floating zone (OFZ) method were examined systematically. X-ray diffraction (XRD) characterization shows that the compound crystallizes in a tetragonal crystal system with the space group I4/mmm (no. 139) with homogenous distribution of the dopants shown via backscattered electron (BSE) imaging. Photoluminescence studies at both 77 K and 298 K reveal that the incorporated lanthanoid ions brightly emit and even show unusual transitions due to the low cutoff phonon energy of the host compound that limits non-radiative loss pathways. Together with a high physical density of ∼6.4 g/cm3, these phosphors could be conceptualized as interesting candidates for X-ray imaging phosphors aiming at high light yields.
在具有低声子能量的各种单晶宿主化合物中合成具有镧系离子发光特性的材料方面取得的进展，促进了众多材料的优化，以满足新能源勘探、发光二极管（LED）、量子点显示器、激光技术、传感器、电信、医疗诊断等不同应用所需的特定光学特性。加强分析镧系元素离子在各种宿主化合物中的发光机理，多年来一直吸引着研究人员，并最终开发出用于光学应用的创新材料。为了更深入地了解加入 Ruddlesden-Popper 型宿主化合物 (La1-xREx)SrGaO4 （RE = Sm、Eu、Ho，x = 0；0.05；0.10）中的 Sm3+、Eu3+ 和 Ho3+ 离子的发光机理，我们对通过光学浮动区 (OFZ) 方法生长的具有均匀活化剂分布的高质量单晶进行了系统研究。X 射线衍射（XRD）表征表明，该化合物在空间群为 I4/mmm（编号 139）的四方晶系中结晶，并通过背散射电子（BSE）成像显示出掺杂剂的均匀分布。在 77 K 和 298 K 两种温度下进行的光致发光研究表明，由于主化合物的低截止声子能量限制了非辐射损失途径，掺入的镧系离子会发出明亮的光，甚至会出现不寻常的转变。这些荧光粉的物理密度高达 6.4 克/立方厘米，因此可被视为具有高光产率的 X 射线成像荧光粉的理想候选材料。
{"title":"Synthesis and optical properties of LaSrGaO4:RE3+ (RE = Sm, Eu, Ho) single crystals via optical float zone method","authors":"Hasan Yilmaz , Masahiko Isobe , Oliver Clemens , Markus Suta , Pascal Puphal","doi":"10.1016/j.omx.2024.100380","DOIUrl":"10.1016/j.omx.2024.100380","url":null,"abstract":"<div><div>The advancement of synthesis of materials with luminescence properties of lanthanoid ions in various single crystalline host compounds with low phonon energies has facilitated the optimization of numerous materials to meet the specific optical properties required for diverse applications such as new energy resource exploration, light-emitting diodes (LEDs), quantum dot displays, laser technology, sensors, telecommunications, medical diagnostics and more. Enhanced analyses of the luminescence mechanism of lanthanoid ions in various host compounds, which have captivated researchers for many years and culminated in the development of innovative materials for optical applications. To obtain a deeper understanding of the luminescence mechanism of Sm<sup>3+</sup>, Eu<sup>3+</sup>, and Ho<sup>3+</sup> ions incorporated into the Ruddlesden-Popper-type host compounds (La<sub>1-<em>x</em></sub><em>RE</em><sub><em>x</em></sub>)SrGaO<sub>4</sub> (<em>RE</em> = Sm, Eu, Ho and <em>x</em> = 0; 0.05; 0.10) high quality single crystals with homogenous activator distribution grown by the optical floating zone (OFZ) method were examined systematically. X-ray diffraction (XRD) characterization shows that the compound crystallizes in a tetragonal crystal system with the space group <em>I</em>4/<em>mmm</em> (no. 139) with homogenous distribution of the dopants shown via backscattered electron (BSE) imaging. Photoluminescence studies at both 77 K and 298 K reveal that the incorporated lanthanoid ions brightly emit and even show unusual transitions due to the low cutoff phonon energy of the host compound that limits non-radiative loss pathways. Together with a high physical density of ∼6.4 g/cm<sup>3</sup>, these phosphors could be conceptualized as interesting candidates for X-ray imaging phosphors aiming at high light yields.</div></div>","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"25 ","pages":"Article 100380"},"PeriodicalIF":0.0,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142720221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-06DOI: 10.1016/j.omx.2024.100378
L. Borkovska , K. Kozoriz , I. Vorona , O. Gudymenko , S. Ponomaryov , O. Melnichuk , V. Trachevskii , O. Chukova , L. Khomenkova
The influence of Li ion on the symmetry of Mn4+ center and its photoluminescence (PL) in MgO:0,01%Mn, 3 % Li ceramics is studied by the X-ray diffraction, electron paramagnetic resonance (EPR), PL and optical absorption methods. It is shown that Li co-doping stimulates conversion of Mn2+ on Mg site into Mn4+ and can decrease symmetry of Mn4+ in a case of their specific close arrangement in the crystal lattice. Two kinds of Mn4+ centers are identified in the EPR and PL spectra: cubic Mn4+ and tetragonal complex Mn4+-Li+. The parameters of corresponding EPR centers are estimated from the experimental spectra (gcub = 1.994, |A|cub = 70.9 × 104 cm−1; g1tetr = g2tetr = 1.994, g3tetr = 1.993, |A|tetr = 71 × 104 cm−1, |D|tetr = 220 × 104 cm−1). The PL lines observed in the low temperature PL spectra are assigned to the specific Mn4+ related centers using a complementary study of PL excitation spectra and temperature dependent PL spectra. The lines at 654 nm and 671 nm are ascribed to R-line of Mn4+ in a site of cubic symmetry and its phonon overtone, correspondingly, as well as the lines at 666 nm and 681 nm are attributed to R2 line of Mn4+ in site with tetragonal symmetry and to its phonon overtone, correspondingly. It is shown that in Mn doped MgO ceramics made without intentional Li co-doping, the cubic Mn4+ center can be present and contribute to the PL spectra.
{"title":"Optical and EPR study of Mn4+ ions in different crystal environments in Mn, Li co-doped MgO","authors":"L. Borkovska , K. Kozoriz , I. Vorona , O. Gudymenko , S. Ponomaryov , O. Melnichuk , V. Trachevskii , O. Chukova , L. Khomenkova","doi":"10.1016/j.omx.2024.100378","DOIUrl":"10.1016/j.omx.2024.100378","url":null,"abstract":"<div><div>The influence of Li ion on the symmetry of Mn<sup>4+</sup> center and its photoluminescence (PL) in MgO:0,01%Mn, 3 % Li ceramics is studied by the X-ray diffraction, electron paramagnetic resonance (EPR), PL and optical absorption methods. It is shown that Li co-doping stimulates conversion of Mn<sup>2+</sup> on Mg site into Mn<sup>4+</sup> and can decrease symmetry of Mn<sup>4+</sup> in a case of their specific close arrangement in the crystal lattice. Two kinds of Mn<sup>4+</sup> centers are identified in the EPR and PL spectra: cubic Mn<sup>4+</sup> and tetragonal complex Mn<sup>4+</sup>-Li<sup>+</sup>. The parameters of corresponding EPR centers are estimated from the experimental spectra (g<sub>cub</sub> = 1.994, |A|<sub>cub</sub> = 70.9 × 10<sup>4</sup> cm<sup>−1</sup>; g<sub>1tetr</sub> = g<sub>2tetr</sub> = 1.994, g<sub>3tetr</sub> = 1.993, |A|<sub>tetr</sub> = 71 × 10<sup>4</sup> cm<sup>−1</sup>, |D|<sub>tetr</sub> = 220 × 10<sup>4</sup> cm<sup>−1</sup>). The PL lines observed in the low temperature PL spectra are assigned to the specific Mn<sup>4+</sup> related centers using a complementary study of PL excitation spectra and temperature dependent PL spectra. The lines at 654 nm and 671 nm are ascribed to R-line of Mn<sup>4+</sup> in a site of cubic symmetry and its phonon overtone, correspondingly, as well as the lines at 666 nm and 681 nm are attributed to R2 line of Mn<sup>4+</sup> in site with tetragonal symmetry and to its phonon overtone, correspondingly. It is shown that in Mn doped MgO ceramics made without intentional Li co-doping, the cubic Mn<sup>4+</sup> center can be present and contribute to the PL spectra.</div></div>","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"24 ","pages":"Article 100378"},"PeriodicalIF":0.0,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-29DOI: 10.1016/j.omx.2024.100377
Adam Watras , Marta Kardach , Katarzyna Szyszka , Paulina Sobierajska , Aleksandra Bartkowiak , Rafal J. Wiglusz
In the present work, a co-precipitation method was employed to prepare nanosized YXO4 (X = V5+, P5+, As5+) doped with Eu3+ ions. The raw nanomaterials have been thermally treated in temperature range between 300 and 1100 °C for 3h. The XRD analysis demonstrated that the powders were single-phase with high crystallite dispersion. The studies focused on investigating the systematic relationship between crystallographic parameters and spectroscopic properties. The average size of the obtained materials was 30 nm for YVO4, 35 nm for YPO4, and 20 nm for YAsO4, respectively.
Moreover, the emission and excitation spectra, although typical for Eu3+ ions, demonstrated some degree of variability with calcination temperatures and doping concentration. Thermal luminescence quenching was typical for YPO4 and YAsO4 samples, while for the YVO4 samples, the intensity of emission increased, reaching its maximum at 725 K. To explain this phenomenon, excitation spectra in function of temperature were measured.
{"title":"Modulation of spectroscopic properties in the YXO4 compounds (where X = V5+, P5+, As5+) doped with Eu3+ ions","authors":"Adam Watras , Marta Kardach , Katarzyna Szyszka , Paulina Sobierajska , Aleksandra Bartkowiak , Rafal J. Wiglusz","doi":"10.1016/j.omx.2024.100377","DOIUrl":"10.1016/j.omx.2024.100377","url":null,"abstract":"<div><div>In the present work, a co-precipitation method was employed to prepare nanosized YXO<sub>4</sub> (X = V<sup>5+</sup>, P<sup>5+</sup>, As<sup>5+</sup>) doped with Eu<sup>3+</sup> ions. The raw nanomaterials have been thermally treated in temperature range between 300 and 1100 °C for 3h. The XRD analysis demonstrated that the powders were single-phase with high crystallite dispersion. The studies focused on investigating the systematic relationship between crystallographic parameters and spectroscopic properties. The average size of the obtained materials was 30 nm for YVO4, 35 nm for YPO<sub>4</sub>, and 20 nm for YAsO<sub>4</sub>, respectively.</div><div>Moreover, the emission and excitation spectra, although typical for Eu<sup>3+</sup> ions, demonstrated some degree of variability with calcination temperatures and doping concentration. Thermal luminescence quenching was typical for YPO<sub>4</sub> and YAsO<sub>4</sub> samples, while for the YVO<sub>4</sub> samples, the intensity of emission increased, reaching its maximum at 725 K. To explain this phenomenon, excitation spectra in function of temperature were measured.</div></div>","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"24 ","pages":"Article 100377"},"PeriodicalIF":0.0,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-17DOI: 10.1016/j.omx.2024.100375
Azamat E. Ryskulov , Igor A. Ivanov , Artem L. Kozlovskiy , Marina Konuhova
The paper presents the results of a study on the application of Raman and UV spectroscopy methods to determine the structural damage kinetics in the near-surface layer of BeO ceramics caused by high-dose irradiation with He2+ ions. Interest in this type of ceramics is due to the combination of its structural and thermophysical parameters, making these ceramics one of the promising classes of materials for microelectronics and structural materials for nuclear reactors, with the possibility of operation in conditions of heightened radiation background. According to the conducted studies, it was established that with the irradiation fluence growth, changes in the nature of deformation structural distortions associated with the accumulation of residual mechanical stresses of tensile and compressive types are observed. At irradiation fluences of 1016–5 × 1016 Не2+/cm2, tensile stresses play a dominant role in structural distortions, while the value of compressive stresses at fluence growth makes up a small share in the overall nature of the deformations. Moreover, an elevation in the irradiation fluence above 5 × 1016 He2+/cm2 leads to a rise in the concentration of defects caused by the formation of oxygen vacancies, as well as He-VO type complexes, the presence of which is indicated by the halo intensity growth in the Raman spectra, as well as a change in the intensity of the absorption bands. Analysis of changes in thermophysical parameters revealed that a rise in structural distortions associated with the accumulation of complex defects results in thermal conductivity reduction and a deterioration in heat transfer processes associated with partial amorphization of the damaged layer. Moreover, the established direct relationship between the value of residual mechanical stresses and the degradation of thermal conductivity indicates the cumulative effect of destructive changes caused by irradiation, as well as the influence of diffusion mechanisms on the damaged layer thickness growth.
{"title":"The effect of residual mechanical stresses and vacancy defects on the diffusion expansion of the damaged layer during irradiation of BeO ceramics","authors":"Azamat E. Ryskulov , Igor A. Ivanov , Artem L. Kozlovskiy , Marina Konuhova","doi":"10.1016/j.omx.2024.100375","DOIUrl":"10.1016/j.omx.2024.100375","url":null,"abstract":"<div><div>The paper presents the results of a study on the application of Raman and UV spectroscopy methods to determine the structural damage kinetics in the near-surface layer of BeO ceramics caused by high-dose irradiation with He<sup>2+</sup> ions. Interest in this type of ceramics is due to the combination of its structural and thermophysical parameters, making these ceramics one of the promising classes of materials for microelectronics and structural materials for nuclear reactors, with the possibility of operation in conditions of heightened radiation background. According to the conducted studies, it was established that with the irradiation fluence growth, changes in the nature of deformation structural distortions associated with the accumulation of residual mechanical stresses of tensile and compressive types are observed. At irradiation fluences of 10<sup>16</sup>–5 × 10<sup>16</sup> Не<sup>2+</sup>/cm<sup>2</sup>, tensile stresses play a dominant role in structural distortions, while the value of compressive stresses at fluence growth makes up a small share in the overall nature of the deformations. Moreover, an elevation in the irradiation fluence above 5 × 10<sup>16</sup> He<sup>2+</sup>/cm<sup>2</sup> leads to a rise in the concentration of defects caused by the formation of oxygen vacancies, as well as He-V<sub>O</sub> type complexes, the presence of which is indicated by the halo intensity growth in the Raman spectra, as well as a change in the intensity of the absorption bands. Analysis of changes in thermophysical parameters revealed that a rise in structural distortions associated with the accumulation of complex defects results in thermal conductivity reduction and a deterioration in heat transfer processes associated with partial amorphization of the damaged layer. Moreover, the established direct relationship between the value of residual mechanical stresses and the degradation of thermal conductivity indicates the cumulative effect of destructive changes caused by irradiation, as well as the influence of diffusion mechanisms on the damaged layer thickness growth.</div></div>","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"24 ","pages":"Article 100375"},"PeriodicalIF":0.0,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-16DOI: 10.1016/j.omx.2024.100376
Bauyrzhan K. Abyshev , Sholpan G. Giniyatova , Artem L. Kozlovskiy
The paper presents the assessment results of the irradiation temperature effect on the change in the type of structural defects caused by irradiation with helium ions in the near-surface layer of Li2ZrO3 ceramics, as well as determining the nature of structural damage using the electron paramagnetic resonance method in the case of irradiation fluence variation. During characterization of the structural changes caused by helium ion irradiation, the main attention was paid to detailing the type of structural defects and radiolysis products arising during irradiation, alongside alterations in their concentration using the electron paramagnetic resonance method. During the experiments, it was determined that the observed effects of thermally stimulated mobility of vacancy defects in the damaged layer caused by irradiation with helium ions indicate a positive effect of thermal heating of samples during irradiation at low fluences. This effect consists in a decline in the number of oxygen vacancies in the damaged layer at low irradiation fluences (1015–1016 cm−2), the concentration of which was determined using the EPR method, and the observed structural changes at low irradiation fluences in the case of an elevation in irradiation temperatures are associated with deformation distortion of the crystalline structure of ceramics caused by transformation energy processes, and thermal expansion effects.
{"title":"Effect of irradiation temperature on the mobility of structural and vacancy defects in the damaged layer of Li2ZrO3 ceramics","authors":"Bauyrzhan K. Abyshev , Sholpan G. Giniyatova , Artem L. Kozlovskiy","doi":"10.1016/j.omx.2024.100376","DOIUrl":"10.1016/j.omx.2024.100376","url":null,"abstract":"<div><div>The paper presents the assessment results of the irradiation temperature effect on the change in the type of structural defects caused by irradiation with helium ions in the near-surface layer of Li<sub>2</sub>ZrO<sub>3</sub> ceramics, as well as determining the nature of structural damage using the electron paramagnetic resonance method in the case of irradiation fluence variation. During characterization of the structural changes caused by helium ion irradiation, the main attention was paid to detailing the type of structural defects and radiolysis products arising during irradiation, alongside alterations in their concentration using the electron paramagnetic resonance method. During the experiments, it was determined that the observed effects of thermally stimulated mobility of vacancy defects in the damaged layer caused by irradiation with helium ions indicate a positive effect of thermal heating of samples during irradiation at low fluences. This effect consists in a decline in the number of oxygen vacancies in the damaged layer at low irradiation fluences (10<sup>15</sup>–10<sup>16</sup> cm<sup>−2</sup>), the concentration of which was determined using the EPR method, and the observed structural changes at low irradiation fluences in the case of an elevation in irradiation temperatures are associated with deformation distortion of the crystalline structure of ceramics caused by transformation energy processes, and thermal expansion effects.</div></div>","PeriodicalId":52192,"journal":{"name":"Optical Materials: X","volume":"24 ","pages":"Article 100376"},"PeriodicalIF":0.0,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号