Bach Do, Sina Jafari Ghalekohneh, Taiwo Adebiyi, Bo Zhao, Ruda Zhang
Nonreciprocal thermal emitters that break Kirchhoff's law of thermal radiation promise exciting applications for thermal and energy applications. The design of the bandwidth and angular range of the nonreciprocal effect, which directly affects the performance of nonreciprocal emitters, typically relies on physical intuition. In this study, we present a general numerical approach to maximize the nonreciprocal effect. We choose doped magneto-optic materials and magnetic Weyl semimetal materials as model materials and focus on pattern-free multilayer structures. The optimization randomly starts from a less effective structure and incrementally improves the broadband nonreciprocity through the combination of Bayesian optimization and reparameterization. Optimization results show that the proposed approach can discover structures that can achieve broadband nonreciprocal emission at wavelengths from 5 to 40 micrometers using only a fewer layers, significantly outperforming current state-of-the-art designs based on intuition in terms of both performance and simplicity.
{"title":"Automated design of nonreciprocal thermal emitters via Bayesian optimization","authors":"Bach Do, Sina Jafari Ghalekohneh, Taiwo Adebiyi, Bo Zhao, Ruda Zhang","doi":"arxiv-2409.09192","DOIUrl":"https://doi.org/arxiv-2409.09192","url":null,"abstract":"Nonreciprocal thermal emitters that break Kirchhoff's law of thermal\u0000radiation promise exciting applications for thermal and energy applications.\u0000The design of the bandwidth and angular range of the nonreciprocal effect,\u0000which directly affects the performance of nonreciprocal emitters, typically\u0000relies on physical intuition. In this study, we present a general numerical\u0000approach to maximize the nonreciprocal effect. We choose doped magneto-optic\u0000materials and magnetic Weyl semimetal materials as model materials and focus on\u0000pattern-free multilayer structures. The optimization randomly starts from a\u0000less effective structure and incrementally improves the broadband\u0000nonreciprocity through the combination of Bayesian optimization and\u0000reparameterization. Optimization results show that the proposed approach can\u0000discover structures that can achieve broadband nonreciprocal emission at\u0000wavelengths from 5 to 40 micrometers using only a fewer layers, significantly\u0000outperforming current state-of-the-art designs based on intuition in terms of\u0000both performance and simplicity.","PeriodicalId":501083,"journal":{"name":"arXiv - PHYS - Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142259969","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}
Subhrajit Mukherjee, Shuhua Wang, Dasari Venkatakrishnarao, Yaoju Tarn, Teymour Talha-Dean, Rainer Lee, Ivan A. Verzhbitskiy, Ding Huang, Abhishek Mishra, John Wellington John, Sarthak Das, Fabio Bussoloti, Thathsara D. Maddumapatabandi, Yee Wen Teh, Yee Sin Ang, Kuan Eng Johnson Goh, Chit Siong Lau
Future electronics require aggressive scaling of channel material thickness while maintaining device performance. Two-dimensional (2D) semiconductors are promising candidates, but despite over two decades of research, experimental performance still lags theoretical expectations. Here, we develop an oxygen-free approach to push the electrical transport of 2D field-effect transistors toward the theoretical phonon-limited intrinsic mobility. We achieve record carrier mobilities of 91 (132) cm2V-1s-1 for mono- (bi-) layer MoS2 transistors on SiO2 substrate. Statistics from over 60 devices confirm that oxygen-free fabrication enhances key figures of merit by more than an order of magnitude. While previous studies suggest that 2D transition metal dichalcogenides such as MoS2 and WS2 are stable in air, we show that short-term ambient exposure can degrade their device performance through irreversible oxygen chemisorption. This study emphasizes the criticality of avoiding oxygen exposure, offering guidance for device manufacturing for fundamental research and practical applications of 2D materials.
{"title":"Toward Phonon-Limited Transport in Two-Dimensional Electronics by Oxygen-Free Fabrication","authors":"Subhrajit Mukherjee, Shuhua Wang, Dasari Venkatakrishnarao, Yaoju Tarn, Teymour Talha-Dean, Rainer Lee, Ivan A. Verzhbitskiy, Ding Huang, Abhishek Mishra, John Wellington John, Sarthak Das, Fabio Bussoloti, Thathsara D. Maddumapatabandi, Yee Wen Teh, Yee Sin Ang, Kuan Eng Johnson Goh, Chit Siong Lau","doi":"arxiv-2409.08453","DOIUrl":"https://doi.org/arxiv-2409.08453","url":null,"abstract":"Future electronics require aggressive scaling of channel material thickness\u0000while maintaining device performance. Two-dimensional (2D) semiconductors are\u0000promising candidates, but despite over two decades of research, experimental\u0000performance still lags theoretical expectations. Here, we develop an\u0000oxygen-free approach to push the electrical transport of 2D field-effect\u0000transistors toward the theoretical phonon-limited intrinsic mobility. We\u0000achieve record carrier mobilities of 91 (132) cm2V-1s-1 for mono- (bi-) layer\u0000MoS2 transistors on SiO2 substrate. Statistics from over 60 devices confirm\u0000that oxygen-free fabrication enhances key figures of merit by more than an\u0000order of magnitude. While previous studies suggest that 2D transition metal\u0000dichalcogenides such as MoS2 and WS2 are stable in air, we show that short-term\u0000ambient exposure can degrade their device performance through irreversible\u0000oxygen chemisorption. This study emphasizes the criticality of avoiding oxygen\u0000exposure, offering guidance for device manufacturing for fundamental research\u0000and practical applications of 2D materials.","PeriodicalId":501083,"journal":{"name":"arXiv - PHYS - Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142259633","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}
SiC structures, including nanowires and films, can be effectively grown on Si substrates through carbonization. However, growth parameters other than temperature, which influence the preferential formation of SiC nanowires or films, have not yet been identified. In this work, we investigate SiC synthesis via Si carbonization using methane (CH$_4$) by varying the growth temperature and the hydrogen to methane gas flow ratio (H$_2$/CH$_4$). We demonstrate that adjusting these parameters allows for the preferential growth of SiC nanowires or films. Specifically, SiC nanowires are preferentially grown when the H$_2$/CH$_4$ ratio exceeds a specific threshold, which varies with the growth temperature, ranging between 1200$^circ$C and 1310$^circ$C. Establishing this precise growth window for SiC nanowires in terms of the H$_2$/CH$_4$ ratio and growth temperature provides new insights into the parameter-driven morphology of SiC. Furthermore, we propose a mechanistic model to explain the preferential growth of either SiC nanowires or films, based on the kinetics of gas-phase reactions and surface processes. These findings not only advance our understanding of SiC growth mechanisms but also pave the way for optimized fabrication strategies for SiC-based nanostructures.
碳化法可以在碳基板上有效地生长出 SiC 结构，包括纳米线和薄膜。然而，除了温度之外，影响 SiC 纳米线或薄膜优先形成的生长参数尚未确定。在这项工作中，我们通过改变生长温度和氢气与甲烷的气体流量比（H$_2$/CH$_4$），研究了利用甲烷（CH$_4$）碳化硅合成碳化硅的方法。我们证明，调整这些参数可以优先生长碳化硅纳米线或薄膜。具体来说，当 H$_2$/CH$_4$ 比率超过特定阈值时，SiC 纳米线就会优先生长，该阈值随生长温度的变化而变化，范围在 1200$^circ$C 和 1310$^circ$C 之间。根据 H$_2$/CH$_4$ 比率和生长温度为碳化硅纳米线建立这一精确的生长窗口，为了解碳化硅的参数驱动形态提供了新的视角。此外，我们还根据气相反应动力学和表面过程，提出了一个解释碳化硅纳米线或薄膜优先生长的机理模型。这些发现不仅加深了我们对碳化硅生长机制的理解，而且为优化基于碳化硅的纳米结构的制造策略铺平了道路。
{"title":"A new critical growth parameter and mechanistic model for SiC nanowire synthesis via Si substrate carbonization: the role of H$_2$/CH$_4$ gas flow ratio","authors":"Junghyun Koo, Chinkyo Kim","doi":"arxiv-2409.09233","DOIUrl":"https://doi.org/arxiv-2409.09233","url":null,"abstract":"SiC structures, including nanowires and films, can be effectively grown on Si\u0000substrates through carbonization. However, growth parameters other than\u0000temperature, which influence the preferential formation of SiC nanowires or\u0000films, have not yet been identified. In this work, we investigate SiC synthesis\u0000via Si carbonization using methane (CH$_4$) by varying the growth temperature\u0000and the hydrogen to methane gas flow ratio (H$_2$/CH$_4$). We demonstrate that\u0000adjusting these parameters allows for the preferential growth of SiC nanowires\u0000or films. Specifically, SiC nanowires are preferentially grown when the\u0000H$_2$/CH$_4$ ratio exceeds a specific threshold, which varies with the growth\u0000temperature, ranging between 1200$^circ$C and 1310$^circ$C. Establishing this\u0000precise growth window for SiC nanowires in terms of the H$_2$/CH$_4$ ratio and\u0000growth temperature provides new insights into the parameter-driven morphology\u0000of SiC. Furthermore, we propose a mechanistic model to explain the preferential\u0000growth of either SiC nanowires or films, based on the kinetics of gas-phase\u0000reactions and surface processes. These findings not only advance our\u0000understanding of SiC growth mechanisms but also pave the way for optimized\u0000fabrication strategies for SiC-based nanostructures.","PeriodicalId":501083,"journal":{"name":"arXiv - PHYS - Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142259963","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}
Md. Moklesur Rahman, Md Kamal Hossain, Fateha Samad, Fysol Ibna Abbas
The thermoelectric characteristics of lead selenium (PbSe) doped with gallium (Ga) are investigated in this study. When the lead sulfide (PbSe) is tuned with appropriate dopants, it exhibits satisfactory ZT values, hence making it a promising thermoelectric material. This study examines the electrical conductivity, Seebeck coefficient, thermal conductivity, and power factor of PbSe, with varying amounts of added Ga. Results indicate that incorporating Ga into PbSe improves its thermoelectric performance, with a maximum ZT value of approximately 1.2 at 873 K for the optimal doping concentration of 0.005 atomic percent. This improvement is attributed to the combined effects of increased electrical conductivity and reduced thermal conductivity. These findings suggest that Ga-doped PbSe is a promising candidate for mid-temperature thermoelectric applications.
本研究探讨了掺杂镓（Ga）的硒化铅（PbSe）的热电特性。当使用适当的掺杂剂对硫化铅（PbSe）进行调谐时，它表现出令人满意的 ZT 值，从而使其成为一种理想的热电材料。本研究考察了添加不同量 Ga 的硒化铅的电导率、塞贝克系数、热导率和功率因数。结果表明，在 PbSe 中加入 Ga 能提高其热电性能，在最佳掺杂浓度为 0.005 原子百分数时，873 K 时的最大 ZT 值约为 1.2。这种改善归因于电导率提高和热导率降低的共同作用。这些发现表明，掺杂镓的硒化铅有望成为中温热电应用的候选材料。
{"title":"A Systematic Investigation of PbSe Thermoelectric Material","authors":"Md. Moklesur Rahman, Md Kamal Hossain, Fateha Samad, Fysol Ibna Abbas","doi":"arxiv-2409.08716","DOIUrl":"https://doi.org/arxiv-2409.08716","url":null,"abstract":"The thermoelectric characteristics of lead selenium (PbSe) doped with gallium\u0000(Ga) are investigated in this study. When the lead sulfide (PbSe) is tuned with\u0000appropriate dopants, it exhibits satisfactory ZT values, hence making it a\u0000promising thermoelectric material. This study examines the electrical\u0000conductivity, Seebeck coefficient, thermal conductivity, and power factor of\u0000PbSe, with varying amounts of added Ga. Results indicate that incorporating Ga\u0000into PbSe improves its thermoelectric performance, with a maximum ZT value of\u0000approximately 1.2 at 873 K for the optimal doping concentration of 0.005 atomic\u0000percent. This improvement is attributed to the combined effects of increased\u0000electrical conductivity and reduced thermal conductivity. These findings\u0000suggest that Ga-doped PbSe is a promising candidate for mid-temperature\u0000thermoelectric applications.","PeriodicalId":501083,"journal":{"name":"arXiv - PHYS - Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142259632","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}
Current research on thermoelectricity is primarily focused on the exploration of materials with enhanced performance, resulting in a lack of fundamental understanding of the thermoelectric effect. Such circumstance is not conducive to the further improvement of the efficiency of thermoelectric conversion. Moreover, available physical images of the derivation of the Kelvin relations are ambiguous. Derivation processes are complex and need a deeper understanding of thermoelectric conversion phenomena. In this paper, a new physical quantity 'thermoelectrical potential' from the physical nature of the thermoelectric conversion is proposed. The quantity is expressed as the product of the Seebeck coefficient and the absolute temperature, i.e., ST. Based on the thermoelectrical potential, we clarify the conversion of the various forms of energy in the thermoelectric effect by presenting a clear physical picture. Results from the analysis of the physical mechanism of the Seebeck effect indicate that the thermoelectrical potential, rather than the temperature gradient field, exerts a force on the charge carriers in the thermoelectric material. Based on thermoelectric potential, the Peltier effects at different material interfaces can be macroscopically described. The Kelvin relation is rederived using the proposed quantity, which simplified the derivation process and elucidated the physical picture of the thermoelectrical conversion.
{"title":"Thermoelectrical potential and derivation of Kelvin relation for thermoelectric materials","authors":"Sikun Chen, Hongxin Zhu, Haidong Wang, Zengyuan Guo","doi":"arxiv-2409.08836","DOIUrl":"https://doi.org/arxiv-2409.08836","url":null,"abstract":"Current research on thermoelectricity is primarily focused on the exploration\u0000of materials with enhanced performance, resulting in a lack of fundamental\u0000understanding of the thermoelectric effect. Such circumstance is not conducive\u0000to the further improvement of the efficiency of thermoelectric conversion.\u0000Moreover, available physical images of the derivation of the Kelvin relations\u0000are ambiguous. Derivation processes are complex and need a deeper understanding\u0000of thermoelectric conversion phenomena. In this paper, a new physical quantity\u0000'thermoelectrical potential' from the physical nature of the thermoelectric\u0000conversion is proposed. The quantity is expressed as the product of the Seebeck\u0000coefficient and the absolute temperature, i.e., ST. Based on the\u0000thermoelectrical potential, we clarify the conversion of the various forms of\u0000energy in the thermoelectric effect by presenting a clear physical picture.\u0000Results from the analysis of the physical mechanism of the Seebeck effect\u0000indicate that the thermoelectrical potential, rather than the temperature\u0000gradient field, exerts a force on the charge carriers in the thermoelectric\u0000material. Based on thermoelectric potential, the Peltier effects at different\u0000material interfaces can be macroscopically described. The Kelvin relation is\u0000rederived using the proposed quantity, which simplified the derivation process\u0000and elucidated the physical picture of the thermoelectrical conversion.","PeriodicalId":501083,"journal":{"name":"arXiv - PHYS - Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142259971","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}
Shuaifeng Li, Yubin Oh, Seong Jae Choi, Panayotis G. Kevrekidis, Jinkyu Yang
Recent advancements in topological metamaterials have unveiled fruitful physics and numerous applications. Whereas initial efforts focus on achieving topologically protected edge states through principles of structural symmetry, the burgeoning field now aspires to customize topological states, tailoring their emergence and frequency. Here, our study presents the realization of topological phase transitions utilizing compliant mechanisms on the facets of Miura-folded metamaterials. This approach induces two opposite topological phases, leading to topological states at the interface. Moreover, we exploit the unique folding behavior of Miura-folded metamaterials to tune the frequency of topological states and dynamically toggle their presence. Our research not only paves the way for inducing topological phase transitions in Miura-folded structures but also enables the on-demand control of topological states, with promising applications in wave manipulation and vibration isolation.
{"title":"On-demand realization of topological states using Miura-folded metamaterials","authors":"Shuaifeng Li, Yubin Oh, Seong Jae Choi, Panayotis G. Kevrekidis, Jinkyu Yang","doi":"arxiv-2409.08064","DOIUrl":"https://doi.org/arxiv-2409.08064","url":null,"abstract":"Recent advancements in topological metamaterials have unveiled fruitful\u0000physics and numerous applications. Whereas initial efforts focus on achieving\u0000topologically protected edge states through principles of structural symmetry,\u0000the burgeoning field now aspires to customize topological states, tailoring\u0000their emergence and frequency. Here, our study presents the realization of\u0000topological phase transitions utilizing compliant mechanisms on the facets of\u0000Miura-folded metamaterials. This approach induces two opposite topological\u0000phases, leading to topological states at the interface. Moreover, we exploit\u0000the unique folding behavior of Miura-folded metamaterials to tune the frequency\u0000of topological states and dynamically toggle their presence. Our research not\u0000only paves the way for inducing topological phase transitions in Miura-folded\u0000structures but also enables the on-demand control of topological states, with\u0000promising applications in wave manipulation and vibration isolation.","PeriodicalId":501083,"journal":{"name":"arXiv - PHYS - Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177898","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}
Linqiang Xu, Yue Hu, Lianqiang Xu, Lin Xu, Qiuhui Li, Aili Wang, Chit Siong Lau, Jing Lu, Yee Sin Ang
Ultrathin oxide semiconductors with sub-1-nm thickness are promising building blocks for ultrascaled field-effect transistor (FET) applications due to their resilience against short-channel effects, high air stability, and potential for low-energy device operation. However, the n-type dominance of ultrathin oxide FET has hindered their integration into complementary metal-oxide-semiconductor (CMOS) technology, which requires both n-and p-type devices. Here we develop an ab initio device-driven computational screening workflow to identify sub-1-nm thickness oxide semiconductors for sub-5-nm FET applications. We demonstrate that ultrathin CaO2, CaO, and SrO are compatible with p-type device operations under both high-performance (HP) and low-power (LP) requirements specified by the International Technology Roadmap of Semiconductors (ITRS), thereby expanding the limited family of p-type oxide semiconductors. Notably, CaO and SrO emerge as the first-of-kind sub-1-nm thickness oxide semiconductors capable of simultaneously meeting the ITRS HP and LP criteria for both n-and p-type devices. CaO and SrO FETs outperform many existing low-dimensional semiconductors, exhibiting scalability below 5-nm gate length. Our findings offer a pioneering effort in the ab initio, device-driven screening of sub-1-nm thickness oxide semiconductors, significantly broadening the material candidate pool for future CMOS technology nodes.
厚度小于 1 纳米的超薄氧化物半导体具有抗短沟道效应的能力、高空气稳定性以及低能耗器件运行的潜力，因此是超大规模场效应晶体管（FET）应用的理想基石。然而，超薄氧化物场效应晶体管的 n 型主导地位阻碍了它们与互补金属氧化物半导体（CMOS）技术的整合，因为该技术同时需要 n 型和 p 型器件。在此，我们开发了一种由器件驱动的计算筛选工作流程，以确定适用于 5 纳米以下场效应晶体管应用的 1 纳米以下厚度氧化物半导体。我们证明了超薄的 CaO2、CaO 和 SrO 与 p 型器件的运行兼容，符合国际半导体技术路线图 (ITRS) 规定的高性能 (HP) 和低功耗 (LP) 要求，从而扩大了有限的 p 型氧化物半导体系列。值得注意的是，氧化钙和氧化锶是首批能够同时满足 ITRS HP 和 LP 标准的 1 纳米以下厚度氧化物半导体，适用于 n 型和 p 型器件。钙氧化物和锶氧化物场效应晶体管的性能优于许多现有的低维半导体，表现出低于 5 纳米栅极长度的可扩展性。我们的研究成果开创性地对 1 纳米以下厚度的氧化物半导体进行了从头开始、器件驱动的筛选，极大地拓宽了未来 CMOS 技术节点的候选材料库。
{"title":"Ab Initio Device-Driven Screening of Sub-1-nm Thickness Oxide Semiconductors for Future CMOS Technology Nodes","authors":"Linqiang Xu, Yue Hu, Lianqiang Xu, Lin Xu, Qiuhui Li, Aili Wang, Chit Siong Lau, Jing Lu, Yee Sin Ang","doi":"arxiv-2409.08096","DOIUrl":"https://doi.org/arxiv-2409.08096","url":null,"abstract":"Ultrathin oxide semiconductors with sub-1-nm thickness are promising building\u0000blocks for ultrascaled field-effect transistor (FET) applications due to their\u0000resilience against short-channel effects, high air stability, and potential for\u0000low-energy device operation. However, the n-type dominance of ultrathin oxide\u0000FET has hindered their integration into complementary metal-oxide-semiconductor\u0000(CMOS) technology, which requires both n-and p-type devices. Here we develop an\u0000ab initio device-driven computational screening workflow to identify sub-1-nm\u0000thickness oxide semiconductors for sub-5-nm FET applications. We demonstrate\u0000that ultrathin CaO2, CaO, and SrO are compatible with p-type device operations\u0000under both high-performance (HP) and low-power (LP) requirements specified by\u0000the International Technology Roadmap of Semiconductors (ITRS), thereby\u0000expanding the limited family of p-type oxide semiconductors. Notably, CaO and\u0000SrO emerge as the first-of-kind sub-1-nm thickness oxide semiconductors capable\u0000of simultaneously meeting the ITRS HP and LP criteria for both n-and p-type\u0000devices. CaO and SrO FETs outperform many existing low-dimensional\u0000semiconductors, exhibiting scalability below 5-nm gate length. Our findings\u0000offer a pioneering effort in the ab initio, device-driven screening of sub-1-nm\u0000thickness oxide semiconductors, significantly broadening the material candidate\u0000pool for future CMOS technology nodes.","PeriodicalId":501083,"journal":{"name":"arXiv - PHYS - Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177906","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}
J. O. Castro, B. Buyatti, D. Mercado, A. Di Donato, M. Quintero, M. Tortarolo
Future neuromorphic architectures will require millions of artificial synapses, making understanding the physical mechanisms behind their plasticity functionalities mandatory. In this work, we propose a simplified spin memristor, where the resistance can be controlled by magnetic field pulses, based on a Co/Pt multilayer with perpendicular magnetic anisotropy as a synapsis emulator. We demonstrate plasticity and spike time dependence plasticity (STDP) in this device and explored the underlying magnetic mechanisms using Kerr microscopy imaging and Hall magneto-transport measurements. A well-defined threshold for magnetization reversal and the continuous resistance states associated with the micromagnetic configuration are the basic properties allowing plasticity and STDP learning mechanisms in this device.
{"title":"Spike-timing-dependent-plasticity learning in a planar magnetic domain wall artificial synapsis","authors":"J. O. Castro, B. Buyatti, D. Mercado, A. Di Donato, M. Quintero, M. Tortarolo","doi":"arxiv-2409.08055","DOIUrl":"https://doi.org/arxiv-2409.08055","url":null,"abstract":"Future neuromorphic architectures will require millions of artificial\u0000synapses, making understanding the physical mechanisms behind their plasticity\u0000functionalities mandatory. In this work, we propose a simplified spin\u0000memristor, where the resistance can be controlled by magnetic field pulses,\u0000based on a Co/Pt multilayer with perpendicular magnetic anisotropy as a\u0000synapsis emulator. We demonstrate plasticity and spike time dependence\u0000plasticity (STDP) in this device and explored the underlying magnetic\u0000mechanisms using Kerr microscopy imaging and Hall magneto-transport\u0000measurements. A well-defined threshold for magnetization reversal and the\u0000continuous resistance states associated with the micromagnetic configuration\u0000are the basic properties allowing plasticity and STDP learning mechanisms in\u0000this device.","PeriodicalId":501083,"journal":{"name":"arXiv - PHYS - Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177899","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}
K. Dulski, E. Beyene, N. Chug, C. Curceanu, E. Czerwiński, M. Das, M. Gorgol, B. Jasińska, K. Kacprzak, Ł. Kapłon, G. Korcyl, T. Kozik, K. Kubat, D. Kumar, E. Lisowski, F. Lisowski, J. Mędrala-Sowa, S. Niedźwiecki, P. Pandey, S. Parzych, E. Perez del Rio, M. Rädler, S. Sharma, M. Skurzok, K. Tayefi, P. Tanty, E. Ł. Stępień, P. Moskal
Positron Annihilation Lifetime Spectroscopy (PALS) is a well-established non-destructive technique used for nanostructural characterization of porous materials. It is based on the annihilation of a positron and an electron. Mean positron lifetime in the material depends on the free voids size and molecular environment, allowing the study of porosity and structural transitions in the nanometer scale. We have developed a novel method enabling spatially resolved PALS, thus providing tomography of nanostructural characterization of an extended object. Correlating space (position) and structural (lifetime) information brings new insight in materials studies, especially in the characterization of the purity and pore distribution. For the first time, a porosity image using stationary positron sources for the simultaneous measurement of the porous polymers XAD4, silica aerogel powder IC3100, and polyvinyl toluene scintillator PVT by the J-PET tomograph is demonstrated
{"title":"Nanoporosity imaging by positronium lifetime tomography","authors":"K. Dulski, E. Beyene, N. Chug, C. Curceanu, E. Czerwiński, M. Das, M. Gorgol, B. Jasińska, K. Kacprzak, Ł. Kapłon, G. Korcyl, T. Kozik, K. Kubat, D. Kumar, E. Lisowski, F. Lisowski, J. Mędrala-Sowa, S. Niedźwiecki, P. Pandey, S. Parzych, E. Perez del Rio, M. Rädler, S. Sharma, M. Skurzok, K. Tayefi, P. Tanty, E. Ł. Stępień, P. Moskal","doi":"arxiv-2409.07963","DOIUrl":"https://doi.org/arxiv-2409.07963","url":null,"abstract":"Positron Annihilation Lifetime Spectroscopy (PALS) is a well-established\u0000non-destructive technique used for nanostructural characterization of porous\u0000materials. It is based on the annihilation of a positron and an electron. Mean\u0000positron lifetime in the material depends on the free voids size and molecular\u0000environment, allowing the study of porosity and structural transitions in the\u0000nanometer scale. We have developed a novel method enabling spatially resolved\u0000PALS, thus providing tomography of nanostructural characterization of an\u0000extended object. Correlating space (position) and structural (lifetime)\u0000information brings new insight in materials studies, especially in the\u0000characterization of the purity and pore distribution. For the first time, a\u0000porosity image using stationary positron sources for the simultaneous\u0000measurement of the porous polymers XAD4, silica aerogel powder IC3100, and\u0000polyvinyl toluene scintillator PVT by the J-PET tomograph is demonstrated","PeriodicalId":501083,"journal":{"name":"arXiv - PHYS - Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177902","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}
Xiaofan Cai, Ruichang Chen, Xu Gao, Meili Yuan, Haixia Hu, Hang Yin, Yuanyuan Qu, Yang Tan, Feng Chen
Recently, avalanche multiplication has been observed in TMDC-based FETs, enhancing sensor performance with high sensitivity. However, the high voltage required for operation can damage the FETs, making it crucial to reduce the breakdown voltage for effective sensing applications. Here, we demonstrate that the utilization of hopping transfer induced by high-density defects can effectively reduce the breakdown voltage in TMDCs FETs. By substituting oxygen atoms for sulfur atoms in a monolayer of MoS2, we create MoS2-xOx, with x carefully adjusted within the range of 0 to 0.51. Oxygen doping reduces the bandgap of TMDCs and enhances ion collision rates. Moreover, higher levels of oxygen doping (x > 0.41) in MoS2-xOx exhibit nearest-neighbor hopping behavior, leading to a significant enhancement in electron mobility. These improvements result in a decrease in the breakdown voltage of avalanche multiplication from 26.2 V to 12.6 V. Additionally, we propose avalanche multiplication in MoS2-xOx as an efficient sensing mechanism to overcome the limitations of gas sensing. The MoS2-xOx sensors display an ultra-high response to NO2 gas in the air, with a response of 5.8x103 % to NO2 gas of 50 ppb at room temperature, which is nearly two orders of magnitude higher than resistance-type gas detectors based on TMDCs. This work demonstrates that hopping transfer induced by high-density oxygen defects can effectively decrease the breakdown voltage of MoS2-xOx FETs, enhancing avalanche multiplication and serving as a promising mechanism for ultrasensitive gas detection.
最近，在基于 TMDC 的场效应晶体管中发现了雪崩倍增现象，从而提高了传感器的性能和灵敏度。然而，工作时所需的高电压会损坏场效应晶体管，因此降低击穿电压对有效传感应用至关重要。在这里，我们证明了利用高密度缺陷诱导的跳变转移可以有效降低 TMDCs FET 的击穿电压。通过用氧原子取代单层 MoS2 中的硫原子，我们创造出了 MoS2-xOx，其 x 值在 0 至 0.51 范围内进行了适当调整。氧掺杂降低了 TMDC 的带隙，提高了离子碰撞率。此外，MoS2-xOx 中较高的氧掺杂水平（x > 0.41）会表现出近邻跳跃行为，从而显著提高电子迁移率。这些改进使得雪崩倍增的击穿电压从 26.2 V 下降到 12.6 V。MoS2-xOx 传感器对空气中的二氧化氮气体具有超高响应，室温下对 50 ppb 二氧化氮气体的响应为 5.8x103%，比基于 TMDC 的电阻型气体探测器高出近两个数量级。这项研究表明，高密度氧缺陷诱导的跳变转移能有效降低 MoS2-xOx FET 的击穿电压，增强雪崩倍增效应，是超灵敏气体检测的一种可行机制。
{"title":"Hopping Transfer Optimizes Avalanche Multiplication in Molybdenum Disulfide","authors":"Xiaofan Cai, Ruichang Chen, Xu Gao, Meili Yuan, Haixia Hu, Hang Yin, Yuanyuan Qu, Yang Tan, Feng Chen","doi":"arxiv-2409.07677","DOIUrl":"https://doi.org/arxiv-2409.07677","url":null,"abstract":"Recently, avalanche multiplication has been observed in TMDC-based FETs,\u0000enhancing sensor performance with high sensitivity. However, the high voltage\u0000required for operation can damage the FETs, making it crucial to reduce the\u0000breakdown voltage for effective sensing applications. Here, we demonstrate that\u0000the utilization of hopping transfer induced by high-density defects can\u0000effectively reduce the breakdown voltage in TMDCs FETs. By substituting oxygen\u0000atoms for sulfur atoms in a monolayer of MoS2, we create MoS2-xOx, with x\u0000carefully adjusted within the range of 0 to 0.51. Oxygen doping reduces the\u0000bandgap of TMDCs and enhances ion collision rates. Moreover, higher levels of\u0000oxygen doping (x > 0.41) in MoS2-xOx exhibit nearest-neighbor hopping behavior,\u0000leading to a significant enhancement in electron mobility. These improvements\u0000result in a decrease in the breakdown voltage of avalanche multiplication from\u000026.2 V to 12.6 V. Additionally, we propose avalanche multiplication in MoS2-xOx\u0000as an efficient sensing mechanism to overcome the limitations of gas sensing.\u0000The MoS2-xOx sensors display an ultra-high response to NO2 gas in the air, with\u0000a response of 5.8x103 % to NO2 gas of 50 ppb at room temperature, which is\u0000nearly two orders of magnitude higher than resistance-type gas detectors based\u0000on TMDCs. This work demonstrates that hopping transfer induced by high-density\u0000oxygen defects can effectively decrease the breakdown voltage of MoS2-xOx FETs,\u0000enhancing avalanche multiplication and serving as a promising mechanism for\u0000ultrasensitive gas detection.","PeriodicalId":501083,"journal":{"name":"arXiv - PHYS - Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177903","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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