Pub Date : 2024-07-08DOI: 10.1088/1361-6463/ad6007
S. Kajita, D. Nishijima
Line intensity ratios (LIRs) of helium (He) atoms are known to depend on electron density, $n_{rm e}$, and temperature, $T_{rm e}$, and thus are widely utilized to evaluate these parameters, which is the so-called He I LIR method. In this conventional method, measured LIRs are compared with theoretical values calculated using a collisional-radiative (CR) model to find the best possible $n_{rm e}$ and $T_{rm e}$. Basic CR models have been improved to take into account several effects. For instance, radiation trapping can occur to a significant degree in weakly ionized plasmas, leading to major alterations of LIRs. This effect has been included with optical escape factors in CR models. A new approach to the evaluation of $n_{rm e}$ and $T_{rm e}$ from He I LIRs has recently been explored using machine learning (ML). In the ML-aided LIR method, a predictive model is developed with training data, which consist of input (measured LIRs) and desired/known output (measured $n_{rm e}$ or $T_{rm e}$ from other diagnostics). It has been demonstrated that this new method predicts $n_{rm e}$ and $T_{rm e}$ better than using the conventional method coupled with a CR model, not only for He but also for other species.
众所周知，氦（He）原子的线强度比（LIR）取决于电子密度（$n_{rm e}$）和温度（$T_{rm e}$），因此被广泛用于评估这些参数，这就是所谓的 He I LIR 方法。在这种传统方法中，测量的 LIR 与使用碰撞辐射（CR）模型计算的理论值进行比较，以找到最佳的 $n_{rm e}$ 和 $T_{rm e}$。基本的碰撞辐射模型已经过改进，以考虑多种效应。例如，在弱电离等离子体中，辐射捕获会在很大程度上发生，从而导致 LIRs 发生重大变化。这种效应已与光学逸散因子一起被纳入 CR 模型。最近，人们利用机器学习（ML）探索了一种新方法来评估He I LIRs中的$n_{rm e}$和$T_{rm e}$。在 ML 辅助 LIR 方法中，利用训练数据开发了一个预测模型，训练数据包括输入（测量的 LIRs）和期望/已知输出（测量的 $n_{rm e}$ 或来自其他诊断的 $T_{rm e}$）。结果表明，这种新方法不仅对氦气，而且对其他物种的 n_{rm e}$ 和 T_{rm e}$ 预测结果都优于使用传统方法和 CR 模型的预测结果。
{"title":"Helium line emission spectroscopy to measure plasma parameters using modeling and machine learning in low temperature plasmas","authors":"S. Kajita, D. Nishijima","doi":"10.1088/1361-6463/ad6007","DOIUrl":"https://doi.org/10.1088/1361-6463/ad6007","url":null,"abstract":"\u0000 Line intensity ratios (LIRs) of helium (He) atoms are known to depend on electron density, $n_{rm e}$, and temperature, $T_{rm e}$, and thus are widely utilized to evaluate these parameters, which is the so-called He I LIR method. In this conventional method, measured LIRs are compared with theoretical values calculated using a collisional-radiative (CR) model to find the best possible $n_{rm e}$ and $T_{rm e}$. Basic CR models have been improved to take into account several effects. For instance, radiation trapping can occur to a significant degree in weakly ionized plasmas, leading to major alterations of LIRs. This effect has been included with optical escape factors in CR models. A new approach to the evaluation of $n_{rm e}$ and $T_{rm e}$ from He I LIRs has recently been explored using machine learning (ML). In the ML-aided LIR method, a predictive model is developed with training data, which consist of input (measured LIRs) and desired/known output (measured $n_{rm e}$ or $T_{rm e}$ from other diagnostics). It has been demonstrated that this new method predicts $n_{rm e}$ and $T_{rm e}$ better than using the conventional method coupled with a CR model, not only for He but also for other species.","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141669413","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 : 2024-07-08DOI: 10.1088/1361-6463/ad6009
Jun Xiong, Qiang Wu, Xinwei Cai, Yiming Zhu, Guangyang Lin, Cheng Li
Monolayer MoS2 is promising candidate for fabrication of optoelectronic devices due to its direct bandgap nature and high carrier mobility. Alkali metal compounds have been demonstrated to be helpful promoters for the growth of large single crystal monolayer MoS2 on SiO2/Si substrate. However, the catalytic mechanism of alkali metal compounds is still under debate. Herein, we compared the surface morphology, optical properties, and electrical properties of monolayer MoS2 flakes grown on SiO2/Si substrate assisted by promoters containing potassium or sodium cations and halogen (chlorine) or non-halogen (hydroxide) anions, i.e., NaCl, NaOH, KCl and KOH. Based on the analysis of existing growth mechanism, we proposed that the alkali metal cation, plays a dominant role in promoting the lateral growth of monolayer MoS2 and obtaining high crystal quality. Furthermore, potassium has a greater promoting effect than sodium. By optimizing growth conditions, monolayer triangular MoS2 flakes with large lateral size over 160 µm were grown assisted by KCl promoter. Raman and PL spectra verified excellent crystal quality of the flakes, with typical electron mobilities of 2.98 and 20 cm2·V-1·s-1 for the back-gated filed effect transistors fabricated on as-grown and fresh SiO2/Si substrates, respectively.
{"title":"Comparative study of sodium and potassium compounds as promoters for growth of monolayer MoS2 with high crystal quality on SiO2/Si substrate","authors":"Jun Xiong, Qiang Wu, Xinwei Cai, Yiming Zhu, Guangyang Lin, Cheng Li","doi":"10.1088/1361-6463/ad6009","DOIUrl":"https://doi.org/10.1088/1361-6463/ad6009","url":null,"abstract":"\u0000 Monolayer MoS2 is promising candidate for fabrication of optoelectronic devices due to its direct bandgap nature and high carrier mobility. Alkali metal compounds have been demonstrated to be helpful promoters for the growth of large single crystal monolayer MoS2 on SiO2/Si substrate. However, the catalytic mechanism of alkali metal compounds is still under debate. Herein, we compared the surface morphology, optical properties, and electrical properties of monolayer MoS2 flakes grown on SiO2/Si substrate assisted by promoters containing potassium or sodium cations and halogen (chlorine) or non-halogen (hydroxide) anions, i.e., NaCl, NaOH, KCl and KOH. Based on the analysis of existing growth mechanism, we proposed that the alkali metal cation, plays a dominant role in promoting the lateral growth of monolayer MoS2 and obtaining high crystal quality. Furthermore, potassium has a greater promoting effect than sodium. By optimizing growth conditions, monolayer triangular MoS2 flakes with large lateral size over 160 µm were grown assisted by KCl promoter. Raman and PL spectra verified excellent crystal quality of the flakes, with typical electron mobilities of 2.98 and 20 cm2·V-1·s-1 for the back-gated filed effect transistors fabricated on as-grown and fresh SiO2/Si substrates, respectively.","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141670010","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 : 2024-07-08DOI: 10.1088/1361-6463/ad600e
Y. Liou, Madeleine Msall, A. Hernández-Mínguez, P. V. Santos
Slanted (or fan-shaped) interdigital transducers (IDTs) with broadband response allow the selective excitation of surface acoustic waves (SAWs) with narrow beam widths and pathways controlled by the excitation frequency. Such SAW-based spatial and frequency control is important for applications in microfluidics, as well as in emerging applications in semiconductor nanostructures. In this contribution, we generate both Rayleigh and Sezawa modes with slanted IDTs on a 4H-SiC substrate coated with a piezoelectric ZnO film. We directly measure the phase wavefronts of narrow SAW beams in the 1200-1260 MHz frequency bandwidth using high-resolution (<1 μm) optical interferometry, and discuss the mechanisms that directly affect the propagation direction and phase profiles of the SAW beams. The combination of multimodal and multi-frequency SAW delay lines provides rich opportunities for SAW-based control of low-dimensional systems, such as electrons in epitaxial graphene or spin centers near the surface of the SiC substrates.
{"title":"Spatial analysis of multi-frequency SAW beams excited by slanted IDTs on ZnO-SiC heterostructures","authors":"Y. Liou, Madeleine Msall, A. Hernández-Mínguez, P. V. Santos","doi":"10.1088/1361-6463/ad600e","DOIUrl":"https://doi.org/10.1088/1361-6463/ad600e","url":null,"abstract":"\u0000 Slanted (or fan-shaped) interdigital transducers (IDTs) with broadband response allow the selective excitation of surface acoustic waves (SAWs) with narrow beam widths and pathways controlled by the excitation frequency. Such SAW-based spatial and frequency control is important for applications in microfluidics, as well as in emerging applications in semiconductor nanostructures. In this contribution, we generate both Rayleigh and Sezawa modes with slanted IDTs on a 4H-SiC substrate coated with a piezoelectric ZnO film. We directly measure the phase wavefronts of narrow SAW beams in the 1200-1260 MHz frequency bandwidth using high-resolution (<1 μm) optical interferometry, and discuss the mechanisms that directly affect the propagation direction and phase profiles of the SAW beams. The combination of multimodal and multi-frequency SAW delay lines provides rich opportunities for SAW-based control of low-dimensional systems, such as electrons in epitaxial graphene or spin centers near the surface of the SiC substrates.","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141667630","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 : 2024-07-08DOI: 10.1088/1361-6463/ad600b
Burak Güneş, B. Butun, Ekmel Özbay
This study explores the impact of alloyed ohmic contact separation on ungated GaN high electron mobility transistors (HEMTs) lattice stress by employing Raman spectroscopy and solid mechanics simulations for comprehensive analysis. Focusing on the substantial stresses exerted by ohmic contacts, our research introduces a novel mechanical calibration procedure. The proposed procedure demonstrates that the stress in the GaN buffer can be precisely modelled using Raman measurements taken from patterns of varying length, which in return reveals the impact of ohmic contacts on stress. We show that this technique shows a good alignment to the Raman measurement results. Moreover, we identify ohmic contact edges as potential sites for defect generation due to the accumulation of substantial elastic energy, a finding supported by experimental observations of crack formations in related studies. Our calibrated mechanical model not only enhances the understanding of stress distributions within GaN HEMTs but also lays the groundwork for future improvements in electro-thermo-mechanical simulations.
本研究采用拉曼光谱和固体力学模拟进行综合分析，探讨合金欧姆触点分离对非栅极氮化镓高电子迁移率晶体管（HEMT）晶格应力的影响。针对欧姆触点产生的巨大应力，我们的研究引入了一种新的机械校准程序。所提出的程序表明，氮化镓缓冲器中的应力可通过不同长度图案的拉曼测量精确建模，从而揭示欧姆触点对应力的影响。我们的研究表明，这项技术与拉曼测量结果非常吻合。此外，由于大量弹性能量的积累，我们发现欧姆接触边缘是产生缺陷的潜在位置，这一发现得到了相关研究中裂纹形成实验观察结果的支持。我们的校准机械模型不仅增强了对 GaN HEMT 内部应力分布的理解，还为今后改进电热力学模拟奠定了基础。
{"title":"Solid-mechanics analysis and modeling of the alloyed ohmic contact proximity in GaN HEMTs using µRaman spectroscopy","authors":"Burak Güneş, B. Butun, Ekmel Özbay","doi":"10.1088/1361-6463/ad600b","DOIUrl":"https://doi.org/10.1088/1361-6463/ad600b","url":null,"abstract":"\u0000 This study explores the impact of alloyed ohmic contact separation on ungated GaN high electron mobility transistors (HEMTs) lattice stress by employing Raman spectroscopy and solid mechanics simulations for comprehensive analysis. Focusing on the substantial stresses exerted by ohmic contacts, our research introduces a novel mechanical calibration procedure. The proposed procedure demonstrates that the stress in the GaN buffer can be precisely modelled using Raman measurements taken from patterns of varying length, which in return reveals the impact of ohmic contacts on stress. We show that this technique shows a good alignment to the Raman measurement results. Moreover, we identify ohmic contact edges as potential sites for defect generation due to the accumulation of substantial elastic energy, a finding supported by experimental observations of crack formations in related studies. Our calibrated mechanical model not only enhances the understanding of stress distributions within GaN HEMTs but also lays the groundwork for future improvements in electro-thermo-mechanical simulations.","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141667281","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 : 2024-07-08DOI: 10.1088/1361-6463/ad600a
M. De Angelis, M. Tomellini
Barium Oxyfluoride plays an important role, as precursor species, in the nucleation and growth of YBa2Cu3O7-δ (YBCO) via the low fluorine Metal Organic Decomposition (MOD low-fluorine) route. In this contribution, we present a study on the thermodynamics of the Oxyfluoride by processing experimental data on the YBCO growth at LaAlO3 (LAO) substrate. The analysis allows one to determine the standard enthalpy and the standard entropy changes for Oxyfluoride formation from Barium oxide and Barium fluoride. To identify the thermodynamically more favorable route to the Oxyfluoride formation in the MOD low-fluorine process, the free energy change for the formation of the precursor, through reactions involving gas water, has been determined. The free energy of formation via fluoride and water indicates higher stability of oxygen rich Oxyfluoride for (P_HF^2)/P_(H_2 O) <10^(-6). In the framework of the nucleation theory the present results are needed to study the effect of precursor composition on film orientation.
{"title":"On the thermodynamics of Barium Oxyfluoride precursor in YBCO growth via MOD process","authors":"M. De Angelis, M. Tomellini","doi":"10.1088/1361-6463/ad600a","DOIUrl":"https://doi.org/10.1088/1361-6463/ad600a","url":null,"abstract":"\u0000 Barium Oxyfluoride plays an important role, as precursor species, in the nucleation and growth of YBa2Cu3O7-δ (YBCO) via the low fluorine Metal Organic Decomposition (MOD low-fluorine) route. In this contribution, we present a study on the thermodynamics of the Oxyfluoride by processing experimental data on the YBCO growth at LaAlO3 (LAO) substrate. The analysis allows one to determine the standard enthalpy and the standard entropy changes for Oxyfluoride formation from Barium oxide and Barium fluoride. To identify the thermodynamically more favorable route to the Oxyfluoride formation in the MOD low-fluorine process, the free energy change for the formation of the precursor, through reactions involving gas water, has been determined. The free energy of formation via fluoride and water indicates higher stability of oxygen rich Oxyfluoride for (P_HF^2)/P_(H_2 O) <10^(-6). In the framework of the nucleation theory the present results are needed to study the effect of precursor composition on film orientation.","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141667673","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 : 2024-07-08DOI: 10.1088/1361-6463/ad600d
Zhoumo Zeng, Hexin Gao, Jin Zhang, Xiaobo Rui, Lei Qi, Yong Chen, Zongyu Wu, Yuhao Cui, Yao Yu, Yu Wu, Yu Zhang
The use of the thermal propellant gauging(TPG) method in mass detection of propellant in aerospace tanks inevitably involves the continuous heating of the tank, and the understanding of the heat transfer mechanism of the tanks in a microgravity environment plays a guiding role in the implementation of the TPG. In this paper, the thermal characteristics of propellant tanks under microgravity are investigated by simulation and it is found that with the weakening of gravity, the heat transfer slows down and 'heat concentration' occurs in the vicinity of the heater. The effect of this property on the implementation of the TPG was then investigated by simulation, and it was found that in the microgravity environment, the accuracy of the TPG detection can be improved by adjusting the locations of the heaters and temperature sensors on the external side of the tank wall.
{"title":"Study of the thermal characteristics of propellant tanks in microgravity and its application to propellant gauging","authors":"Zhoumo Zeng, Hexin Gao, Jin Zhang, Xiaobo Rui, Lei Qi, Yong Chen, Zongyu Wu, Yuhao Cui, Yao Yu, Yu Wu, Yu Zhang","doi":"10.1088/1361-6463/ad600d","DOIUrl":"https://doi.org/10.1088/1361-6463/ad600d","url":null,"abstract":"\u0000 The use of the thermal propellant gauging(TPG) method in mass detection of propellant in aerospace tanks inevitably involves the continuous heating of the tank, and the understanding of the heat transfer mechanism of the tanks in a microgravity environment plays a guiding role in the implementation of the TPG. In this paper, the thermal characteristics of propellant tanks under microgravity are investigated by simulation and it is found that with the weakening of gravity, the heat transfer slows down and 'heat concentration' occurs in the vicinity of the heater. The effect of this property on the implementation of the TPG was then investigated by simulation, and it was found that in the microgravity environment, the accuracy of the TPG detection can be improved by adjusting the locations of the heaters and temperature sensors on the external side of the tank wall.","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141670061","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 : 2024-07-05DOI: 10.1088/1361-6463/ad5f98
Zhenlai Wang, Mengjian Zhu
The Moiré superlattice formed by twisting two-dimensional materials at a certain angle has become an exciting platform for studying new properties of two-dimensional materials. Due to the introduction of new periodic potentials, Moiré super-lattices can generate a series of exotic physical phenomena, for instance, Moiré excitons, unconventional superconductivity, topological phase transitions, and so on. Non-destructive characterization methods such as spectroscopic characterization and microscopy techniques are powerful tools for investigating the structural and electronic properties of Moiré superlat-tices. This review tries to provide a comprehensive introduction to typical spectroscopic methods such as Raman spectros-copy, photoluminescence spectroscopy, angle-resolved photoemission spectroscopy, and the contributions of microscopy techniques such as scanning near-field optical microscopy in characterizations of Moiré superlattices. We summarize the latest progress made in the field of Moiré superlattices with the help of these techniques and discuss the advantages of dif-ferent characterization methods.
{"title":"Spectroscopy and microscopy characterizations of two-dimensional materials with Moiré superlattices","authors":"Zhenlai Wang, Mengjian Zhu","doi":"10.1088/1361-6463/ad5f98","DOIUrl":"https://doi.org/10.1088/1361-6463/ad5f98","url":null,"abstract":"\u0000 The Moiré superlattice formed by twisting two-dimensional materials at a certain angle has become an exciting platform for studying new properties of two-dimensional materials. Due to the introduction of new periodic potentials, Moiré super-lattices can generate a series of exotic physical phenomena, for instance, Moiré excitons, unconventional superconductivity, topological phase transitions, and so on. Non-destructive characterization methods such as spectroscopic characterization and microscopy techniques are powerful tools for investigating the structural and electronic properties of Moiré superlat-tices. This review tries to provide a comprehensive introduction to typical spectroscopic methods such as Raman spectros-copy, photoluminescence spectroscopy, angle-resolved photoemission spectroscopy, and the contributions of microscopy techniques such as scanning near-field optical microscopy in characterizations of Moiré superlattices. We summarize the latest progress made in the field of Moiré superlattices with the help of these techniques and discuss the advantages of dif-ferent characterization methods.","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141675757","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 : 2024-07-05DOI: 10.1088/1361-6463/ad5f97
Jing Zhao, Runkang Lin, Jinyao Wang, Jiaqian Sun, Keqian Dong, Huayi Zou, Jiangying Lu, Jingteng Ma, Shudi Lu, Fangyuan Ma, Kong Liu, S. Yue, Zhijie Wang, S. Qu
Plasmonic laser has great potential to overcome the optical diffraction limit, playing a crucial role in advancing nanophotonics and nanoelectronics for on-chip integration. However, current plasmonic lasers face several challenges, such as the difficulty in controlling nanowire size, disordered arrangement, and complicated fabrication process. Herein, ultra-thin gain media for plasmonic lasers below the cutoff size of the photonic mode are prepared using the PDMS-assisted imprinting. This method enables precise control over the size of the perovskite nanowire, with the minimum size achievable being 60 nm. As a result, the plasmonic lasing is achieved from the CsPbBr3 nanowire-based device with a threshold as low as ~49.13 μJ cm-2 and a Quality Factor (Q) of 1803 at room temperature, demonstrating its capability for achieving high-quality lasing. Meanwhile, a dual-pumping time-resolved fluorescence study suggests that the radiative recombination lifetime of CsPbBr3 nanowires is shortened by a factor of 10 due to the Purcell effect, confirming the plasmonic effect exhibited by the device. Furthermore, a plasmonic laser array is developed using this method, demonstrating the applicability of the imprinting method in complex graphic fabrication. This breakthrough provides a solution for the application of plasmonic laser arrays in optoelectronic integration.
{"title":"Ultra-thin size-controllable surface plasmon polariton laser by PDMS-assisted imprinting","authors":"Jing Zhao, Runkang Lin, Jinyao Wang, Jiaqian Sun, Keqian Dong, Huayi Zou, Jiangying Lu, Jingteng Ma, Shudi Lu, Fangyuan Ma, Kong Liu, S. Yue, Zhijie Wang, S. Qu","doi":"10.1088/1361-6463/ad5f97","DOIUrl":"https://doi.org/10.1088/1361-6463/ad5f97","url":null,"abstract":"\u0000 Plasmonic laser has great potential to overcome the optical diffraction limit, playing a crucial role in advancing nanophotonics and nanoelectronics for on-chip integration. However, current plasmonic lasers face several challenges, such as the difficulty in controlling nanowire size, disordered arrangement, and complicated fabrication process. Herein, ultra-thin gain media for plasmonic lasers below the cutoff size of the photonic mode are prepared using the PDMS-assisted imprinting. This method enables precise control over the size of the perovskite nanowire, with the minimum size achievable being 60 nm. As a result, the plasmonic lasing is achieved from the CsPbBr3 nanowire-based device with a threshold as low as ~49.13 μJ cm-2 and a Quality Factor (Q) of 1803 at room temperature, demonstrating its capability for achieving high-quality lasing. Meanwhile, a dual-pumping time-resolved fluorescence study suggests that the radiative recombination lifetime of CsPbBr3 nanowires is shortened by a factor of 10 due to the Purcell effect, confirming the plasmonic effect exhibited by the device. Furthermore, a plasmonic laser array is developed using this method, demonstrating the applicability of the imprinting method in complex graphic fabrication. This breakthrough provides a solution for the application of plasmonic laser arrays in optoelectronic integration.","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141675017","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 : 2024-07-05DOI: 10.1088/1361-6463/ad5f99
Jiří Fujera, P. Hoffer, V. Prukner, P. Rotondo, G. Arora, V. Jirásek, Petr Lukes, Milan Šimek
Surface DBD discharge maintained in moist air in the immediate vicinity of the water surface is an effective source of reactive species for the production of plasma-activated water. In this work, we investigated the water activation process for two different DBD energization methods; i.e. using periodic HV pulses with nanosecond risetimes and amplitude-modulated HV AC. We combined UV-vis-NIR ICCD spectroscopy with electrical characteristics to determine the basic characteristics of surface DBD microfilaments. Formation of N2O5/NO2/N2O/H2O2/NO2-/NO3- species was followed and the production yields of species generated in plasma-activated water (H2O2/NO2-/NO3-) were determined in a flow-through reactor under well-defined and stable discharge conditions. Both energization methods reached comparable energy efficiencies of nitrogen fixation in the range of 1-6 g/kWh with minimal concentrations of H2O2 (10s µM). However, the AC-powered SDBD produced mainly NO3- with minimal NO2- (1/10 of NO3-), while in the case of pulsed SDBD the better-balanced NO2-/NO3- ratio was achieved.
{"title":"Surface DBD in moist air for nitrogen fixation: a comparative study of pulsed versus amplitude-modulated AC powered discharge","authors":"Jiří Fujera, P. Hoffer, V. Prukner, P. Rotondo, G. Arora, V. Jirásek, Petr Lukes, Milan Šimek","doi":"10.1088/1361-6463/ad5f99","DOIUrl":"https://doi.org/10.1088/1361-6463/ad5f99","url":null,"abstract":"\u0000 Surface DBD discharge maintained in moist air in the immediate vicinity of the water surface is an effective source of reactive species for the production of plasma-activated water. In this work, we investigated the water activation process for two different DBD energization methods; i.e. using periodic HV pulses with nanosecond risetimes and amplitude-modulated HV AC. We combined UV-vis-NIR ICCD spectroscopy with electrical characteristics to determine the basic characteristics of surface DBD microfilaments. Formation of N2O5/NO2/N2O/H2O2/NO2-/NO3- species was followed and the production yields of species generated in plasma-activated water (H2O2/NO2-/NO3-) were determined in a flow-through reactor under well-defined and stable discharge conditions. Both energization methods reached comparable energy efficiencies of nitrogen fixation in the range of 1-6 g/kWh with minimal concentrations of H2O2 (10s µM). However, the AC-powered SDBD produced mainly NO3- with minimal NO2- (1/10 of NO3-), while in the case of pulsed SDBD the better-balanced NO2-/NO3- ratio was achieved.","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141677012","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}
The demand for nonlinear magnetic fields (NMF) spans diverse domains, encompassing medical applications like drug transportation and aerospace applications such as attitude control. Existing designs of magnetic field coils predominantly focus on uniform and gradient fields as the complexity of magnetic field distribution often leads to intricate solution processes. This paper presents a novel approach to coil design, addressing the challenge of NMF distribution by reconstructing the characteristic matrix within the traditional target field method (TFM). To solve the overdetermined equations involved, we incorporate an improved particle swarm optimization (IPSO) algorithm into the TFM framework. A pair of symmetrical and asymmetrical coils are designed and the effectiveness of this method is verified by comparing the simulated and experimental results.
{"title":"Biplanar Coils Design for Spatial Nonlinear Magnetic Fields Using An Enhanced Target Field Method","authors":"Shuai-Jie Yuan, Peiling Cui, Minxia Shi, Xu Zhang, Jianzhi Yang, Leran Zhang, Yuzheng Ma","doi":"10.1088/1361-6463/ad5f9a","DOIUrl":"https://doi.org/10.1088/1361-6463/ad5f9a","url":null,"abstract":"\u0000 The demand for nonlinear magnetic fields (NMF) spans diverse domains, encompassing medical applications like drug transportation and aerospace applications such as attitude control. Existing designs of magnetic field coils predominantly focus on uniform and gradient fields as the complexity of magnetic field distribution often leads to intricate solution processes. This paper presents a novel approach to coil design, addressing the challenge of NMF distribution by reconstructing the characteristic matrix within the traditional target field method (TFM). To solve the overdetermined equations involved, we incorporate an improved particle swarm optimization (IPSO) algorithm into the TFM framework. A pair of symmetrical and asymmetrical coils are designed and the effectiveness of this method is verified by comparing the simulated and experimental results.","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141676702","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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