Pub Date : 2024-11-21DOI: 10.1016/j.mtphys.2024.101599
Koichi Tanaka, Connor P. Horn, Jianguo Wen, Rachel E. Koritala, Supratik Guha
In this paper, we demonstrate the crystallization of an amorphous Si layer via atomic imprint crystallization (AIC), where an amorphous Si layer is crystallized by solid phase epitaxy (SPE) from an externally impressed single-crystal Si template that is then peeled off via delamination following crystallization. Microstructural analysis using electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM) studies of the delaminated (crystallized) films reveals that the top surface of the amorphous Si layer is crystallized by SPE with regions (up to ∼5 mm diameter) composed of epitaxial domains (lateral size of few μm), all of which bear the same crystalline orientation as that of the template crystal. Unlike conventional SPE, the crystallization is not uniform across the entire region: the grains contain crystal defects such as dislocations, stacking faults, and twins; and while the crystallization is initiated at the top surface of the film, the thickness of the single-crystalline area is limited to ∼40 nm from the top surface. Clearly, the AIC approach leads to SPE (aligned with the template’s crystalline orientation) over areas as large as few mms, but the crystallization is defective and incomplete through the film. We attribute this to be a consequence of the tensile stress field created at the amorphous/crystalline frontline by the volume change of amorphous Si during the crystallization. Our results establish the feasibility of imprint crystallization, and points to the direction of a new process that may enable the creation of single crystal pockets in integrated device stacks in a scalable fashion without the need for an underlying single crystal substrate. However, our results also indicate that the crystallization is of a poor quality and indicates the need for further optimization of the crystallization method.
{"title":"Atomic Imprint Crystallization: Externally-Templated Crystallization of Amorphous Silicon","authors":"Koichi Tanaka, Connor P. Horn, Jianguo Wen, Rachel E. Koritala, Supratik Guha","doi":"10.1016/j.mtphys.2024.101599","DOIUrl":"https://doi.org/10.1016/j.mtphys.2024.101599","url":null,"abstract":"In this paper, we demonstrate the crystallization of an amorphous Si layer via atomic imprint crystallization (AIC), where an amorphous Si layer is crystallized by solid phase epitaxy (SPE) from an externally impressed single-crystal Si template that is then peeled off via delamination following crystallization. Microstructural analysis using electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM) studies of the delaminated (crystallized) films reveals that the top surface of the amorphous Si layer is crystallized by SPE with regions (up to ∼5 mm diameter) composed of epitaxial domains (lateral size of few μm), all of which bear the same crystalline orientation as that of the template crystal. Unlike conventional SPE, the crystallization is not uniform across the entire region: the grains contain crystal defects such as dislocations, stacking faults, and twins; and while the crystallization is initiated at the top surface of the film, the thickness of the single-crystalline area is limited to ∼40 nm from the top surface. Clearly, the AIC approach leads to SPE (aligned with the template’s crystalline orientation) over areas as large as few mms, but the crystallization is defective and incomplete through the film. We attribute this to be a consequence of the tensile stress field created at the amorphous/crystalline frontline by the volume change of amorphous Si during the crystallization. Our results establish the feasibility of imprint crystallization, and points to the direction of a new process that may enable the creation of single crystal pockets in integrated device stacks in a scalable fashion without the need for an underlying single crystal substrate. However, our results also indicate that the crystallization is of a poor quality and indicates the need for further optimization of the crystallization method.","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"60 1","pages":""},"PeriodicalIF":11.5,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mist chemical vapor deposition (mist CVD) technology originated from early metal organic chemical vapor deposition (MOCVD) techniques. By mist CVD, High-quality oxide films are deposited by ultrasonic atomization of low-concentration precursor solutions under atmospheric pressure and relatively low temperature conditions. Mist CVD was first reported in 1990, and in 2008, Shinohara et al. applied mist CVD to the growth of gallium oxide (Ga2O3) epitaxial films. As an ultrawide bandgap (UWBG) semiconductor, Ga2O3 has tremendous potential in power systems and optoelectronic devices, attracting significant attention and becoming a research hotspot in recent years. Various techniques have been explored for growing Ga2O3 films. Among them, mist CVD is noted for its relatively cheap equipment, simpler operation, and competitive cost advantages, making it a promising method for Ga2O3 film growth. Using mist CVD, five crystal phases (α, β, γ, ε, and δ) of Ga2O3 films have been successfully produced, and the properties of Ga2O3 films can be easily tuned through doping and alloy engineering. Additionally, semiconductor devices have been fabricated using Ga2O3 films grown by mist CVD. However, challenges remain in terms of doping uniformity, crystal phase purity, and stability. This paper reviews the advancements in mist CVD for the deposition of Ga2O3, covering mist CVD equipment design, Ga2O3 crystal phase control, doping and alloy modulation, and device fabrication.
{"title":"Mist CVD Technology for Gallium Oxide Deposition: A Review","authors":"Suhao Yao, Yifan Yao, Maolin Zhang, Xueqiang Ji, Shan Li, Weihua Tang","doi":"10.1016/j.mtphys.2024.101604","DOIUrl":"https://doi.org/10.1016/j.mtphys.2024.101604","url":null,"abstract":"Mist chemical vapor deposition (mist CVD) technology originated from early metal organic chemical vapor deposition (MOCVD) techniques. By mist CVD, High-quality oxide films are deposited by ultrasonic atomization of low-concentration precursor solutions under atmospheric pressure and relatively low temperature conditions. Mist CVD was first reported in 1990, and in 2008, Shinohara et al. applied mist CVD to the growth of gallium oxide (Ga<sub>2</sub>O<sub>3</sub>) epitaxial films. As an ultrawide bandgap (UWBG) semiconductor, Ga<sub>2</sub>O<sub>3</sub> has tremendous potential in power systems and optoelectronic devices, attracting significant attention and becoming a research hotspot in recent years. Various techniques have been explored for growing Ga<sub>2</sub>O<sub>3</sub> films. Among them, mist CVD is noted for its relatively cheap equipment, simpler operation, and competitive cost advantages, making it a promising method for Ga<sub>2</sub>O<sub>3</sub> film growth. Using mist CVD, five crystal phases (<em>α</em>, <em>β</em>, <em>γ</em>, <em>ε</em>, and <em>δ</em>) of Ga<sub>2</sub>O<sub>3</sub> films have been successfully produced, and the properties of Ga<sub>2</sub>O<sub>3</sub> films can be easily tuned through doping and alloy engineering. Additionally, semiconductor devices have been fabricated using Ga<sub>2</sub>O<sub>3</sub> films grown by mist CVD. However, challenges remain in terms of doping uniformity, crystal phase purity, and stability. This paper reviews the advancements in mist CVD for the deposition of Ga<sub>2</sub>O<sub>3</sub>, covering mist CVD equipment design, Ga<sub>2</sub>O<sub>3</sub> crystal phase control, doping and alloy modulation, and device fabrication.","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"252 1","pages":""},"PeriodicalIF":11.5,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The p-type doping is one of the main challenges of the emerging semiconductor β-Ga2O3 technology. Phosphorus implantation has been recently reported as a novel route to achieve p-type conduction on Ga2O3 at room temperature. Here, P-implanted epilayers, grown onto c-plane sapphire revealed a pseudo-metallic behavior (ρ = 1.3 – 0.3 Ω·cm) in the 300 – 600 K range with a hole carrier concentration of p ⁓ 4 – 6 ×1018 cm-3 and hole mobility of μ = 1.2 – 2.1 cm2/(V·s). At sufficiently low temperature, a metal-insulator transition arises together with an increase in the positive magnetoresistance, reaching up to 200% (9 T) large positive magneto resistance effect at 2 K. It is suggested that an Anderson delocalization model explains the room temperature conduction, and the transition to an insulator state caused by random variation of potential related to the incorporated phosphorous in Ga2O3. We believe that the lack of shallow acceptors can be mitigated by promoting Anderson disorder through the incorporation of a high level of acceptor impurities.
p 型掺杂是新兴半导体 β-Ga2O3 技术面临的主要挑战之一。最近有报道称，磷植入是在室温下实现 Ga2O3 p 型传导的一种新方法。在这里，生长在 c 平面蓝宝石上的磷植入外延层在 300 - 600 K 范围内显示出假金属行为（ρ = 1.3 - 0.3 Ω-cm），空穴载流子浓度为 p ⁓ 4 - 6 ×1018 cm-3，空穴迁移率为 μ = 1.2 - 2.1 cm2/（V-s）。在足够低的温度下，会出现金属-绝缘体转变，同时正磁阻增加，在 2 K 时达到 200% (9 T) 的大正磁阻效应。有人认为，安德森析出模型可以解释室温传导，而向绝缘体状态的转变是由与 Ga2O3 中的磷结合相关的电位随机变化引起的。我们认为，可以通过加入高水平的受体杂质来促进安德森无序，从而缓解浅层受体的缺乏。
{"title":"Anderson disorder related p-type conductivity and metal-insulator transition in β-Ga2O3","authors":"Zeyu Chi, Se-Rim Park, Luka Burdiladze, Tamar Tchelidze, Jean-Michel Chauveau, Yves Dumont, Sang-Mo Koo, Zurab Kushitashvili, Amiran Bibilashvili, Gérard Guillot, Amador Pérez-Tomás, Xin-Ying Tsai, Fu-Gow Tarntair, Ray Hua Horng, Ekaterine Chikoidze","doi":"10.1016/j.mtphys.2024.101602","DOIUrl":"https://doi.org/10.1016/j.mtphys.2024.101602","url":null,"abstract":"The <em>p</em>-type doping is one of the main challenges of the emerging semiconductor <em>β-</em>Ga<sub>2</sub>O<sub>3</sub> technology. Phosphorus implantation has been recently reported as a novel route to achieve <em>p</em>-type conduction on Ga<sub>2</sub>O<sub>3</sub> at room temperature. Here, P-implanted epilayers, grown onto <em>c</em>-plane sapphire revealed a pseudo-metallic behavior (<em>ρ</em> = 1.3 – 0.3 Ω·cm) in the 300 – 600 K range with a hole carrier concentration of <em>p</em> ⁓ 4 – 6 ×10<sup>18</sup> cm<sup>-3</sup> and hole mobility of <em>μ</em> = 1.2 – 2.1 cm<sup>2</sup>/(V·s). At sufficiently low temperature, a metal-insulator transition arises together with an increase in the positive magnetoresistance, reaching up to 200% (9 T) large positive magneto resistance effect at 2 K. It is suggested that an Anderson delocalization model explains the room temperature conduction, and the transition to an insulator state caused by random variation of potential related to the incorporated phosphorous in Ga<sub>2</sub>O<sub>3</sub>. We believe that the lack of shallow acceptors can be mitigated by promoting Anderson disorder through the incorporation of a high level of acceptor impurities.","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"2 1","pages":""},"PeriodicalIF":11.5,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142679111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Achieving effective control of thermal and mechanical distributions has been a long-standing goal, and metamaterials have emerged as a crucial tool for customizing functional structures to manipulate these physical fields. However, existing design paradigms do not apply to thermal-mechanical metamaterials that operate on thermal and mechanical fields simultaneously and independently. First, Due to the different geometric requirements imposed by the thermal and mechanical fields on the unit cells, there is a conflict between functional coupling and design coupling, which limits the design of thermal-mechanical metamaterials. Second, the fact that continuum mechanical equations do not remain invariant under general coordinate transformations hinders the application of conventional theories. Additionally, balancing minimal design costs, manufacturability, and optimal functionality remains a significant challenge. Here, we propose a global data-driven design method using Bayesian hyperparameter optimization. This method creates thermal-mechanical metamaterials from a large, pre-computed unit cell database. Our flexible method allows designing thermal-mechanical metamaterials with various functional combinations (e.g., cloaks, concentrators, and rotators) and shapes. Compared to traditional solutions, this approach balances manufacturability and functionality while offering unparalleled universality and low design costs. Experimental measurements validate the effectiveness of our method. Our approach can rapidly respond to new design scenarios and address design challenges related to the multi-physical effects.
{"title":"Data-driven design of thermal-mechanical multifunctional metamaterials","authors":"Xiaochang Xing, Yanxiang Wang, Jianchang Jiang, Lingling Wu, Xiaoyong Tian, Ying Li","doi":"10.1016/j.mtphys.2024.101603","DOIUrl":"https://doi.org/10.1016/j.mtphys.2024.101603","url":null,"abstract":"Achieving effective control of thermal and mechanical distributions has been a long-standing goal, and metamaterials have emerged as a crucial tool for customizing functional structures to manipulate these physical fields. However, existing design paradigms do not apply to thermal-mechanical metamaterials that operate on thermal and mechanical fields simultaneously and independently. First, Due to the different geometric requirements imposed by the thermal and mechanical fields on the unit cells, there is a conflict between functional coupling and design coupling, which limits the design of thermal-mechanical metamaterials. Second, the fact that continuum mechanical equations do not remain invariant under general coordinate transformations hinders the application of conventional theories. Additionally, balancing minimal design costs, manufacturability, and optimal functionality remains a significant challenge. Here, we propose a global data-driven design method using Bayesian hyperparameter optimization. This method creates thermal-mechanical metamaterials from a large, pre-computed unit cell database. Our flexible method allows designing thermal-mechanical metamaterials with various functional combinations (e.g., cloaks, concentrators, and rotators) and shapes. Compared to traditional solutions, this approach balances manufacturability and functionality while offering unparalleled universality and low design costs. Experimental measurements validate the effectiveness of our method. Our approach can rapidly respond to new design scenarios and address design challenges related to the multi-physical effects.","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"3 1","pages":""},"PeriodicalIF":11.5,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
CaBi2Nb2O9 (CBNO) ceramics exhibit significant potential in the development of piezoelectric sensors suitable for extreme environments such as aerospace, metallurgy, and nuclear power plants. While previous studies have enhanced the piezoelectric response of CBNO ceramics, their insulating properties at high temperatures still require improvement. In this work, co-substitution of (Li0.5Bi0.5) at A site and Mn at B site was designed to improve the electrical properties of CBNO ceramics. Defect dipoles induced by the bound between Mn and oxygen vacancies restrict the movement of oxygen vacancies at high temperatures. Meanwhile, co-substitution of Ca by (Li0.5Bi0.5) reduces both the sintering temperature and volatilization of Bi2O3 during the sintering process. This modification results in an ultra-high TC of 928 °C and an exceptional resistivity of 2.85 MΩ·cm at 600 °C for Ca0.96(Li0.5Bi0.5)0.04Bi2Nb1.98Mn0.02O9 ceramics. Furthermore, the ceramic exhibits excellent piezoelectric properties (d33 of 15.2 pC/N and kp of 6.9%), ferroelectric properties (Pr of 9.42 μC/cm2), and thermal stability (degeneration of d33 only 6% after annealing at 900 °C for 2 h). This work offers a practical strategy for simultaneously achieving both a high piezoelectric response and outstanding insulating properties in the CBNO system.
{"title":"Achieving ultra-high resistivity and outstanding piezoelectric properties by co-substitution in CaBi2Nb2O9 ceramics","authors":"Biao Zhang, Liming Quan, Zhihong Luo, Qiantong Li, Jianming Deng, Shuhang Yu, Wangxin Li, Mingmei Lin, Feng Yan, Dawei Wang, Dongyan Yu, Changbai Long, Laijun Liu","doi":"10.1016/j.mtphys.2024.101598","DOIUrl":"https://doi.org/10.1016/j.mtphys.2024.101598","url":null,"abstract":"CaBi<sub>2</sub>Nb<sub>2</sub>O<sub>9</sub> (CBNO) ceramics exhibit significant potential in the development of piezoelectric sensors suitable for extreme environments such as aerospace, metallurgy, and nuclear power plants. While previous studies have enhanced the piezoelectric response of CBNO ceramics, their insulating properties at high temperatures still require improvement. In this work, co-substitution of (Li<sub>0.5</sub>Bi<sub>0.5</sub>) at A site and Mn at B site was designed to improve the electrical properties of CBNO ceramics. Defect dipoles induced by the bound between Mn and oxygen vacancies restrict the movement of oxygen vacancies at high temperatures. Meanwhile, co-substitution of Ca by (Li<sub>0.5</sub>Bi<sub>0.5</sub>) reduces both the sintering temperature and volatilization of Bi<sub>2</sub>O<sub>3</sub> during the sintering process. This modification results in an ultra-high <em>T</em><sub>C</sub> of 928 °C and an exceptional resistivity of 2.85 MΩ·cm at 600 °C for Ca<sub>0.96</sub>(Li<sub>0.5</sub>Bi<sub>0.5</sub>)<sub>0.04</sub>Bi<sub>2</sub>Nb<sub>1.98</sub>Mn<sub>0.02</sub>O<sub>9</sub> ceramics. Furthermore, the ceramic exhibits excellent piezoelectric properties (<em>d</em><sub>33</sub> of 15.2 pC/N and <em>k</em><sub>p</sub> of 6.9%), ferroelectric properties (<em>P</em><sub>r</sub> of 9.42 μC/cm<sup>2</sup>), and thermal stability (degeneration of <em>d</em><sub>33</sub> only 6% after annealing at 900 °C for 2 h). This work offers a practical strategy for simultaneously achieving both a high piezoelectric response and outstanding insulating properties in the CBNO system.","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"11 1","pages":""},"PeriodicalIF":11.5,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The climate crisis and the need for green and sustainable energy drive the rapid development of hydrogen production from water electrolysis. Improvements in the kinetics of the anode reaction, which governs the efficiency of water electrolysis, are essential for efficient hydrogen production and key to effectively addressing global environmental and energy challenges. Hence, we focus on improving the kinetics of the anode oxidation reaction. The multi-walled carbon nanotubes coupled with bimetallic organic framework (CoFe-MOF-74) composite electrocatalysts (CoFe-MOF-74@MWCNT) were fabricated for OER and the kinetically more favorable glucose oxidation reaction (GOR). Compared to commercial RuO2, CoFe-MOF-74@MWCNT showed superior OER catalytic performance, exhibiting a lower overpotential (273 mV) and a lower Tafel slope (55 mV dec-1) at a current density of 10 mA cm-2. Moreover, after adding glucose to the anode, the potential required of 10 mA cm-2 was only 1.291 V (vs. RHE), a reduction of 212 mV compared to the OER potential. This reduction in potential demonstrates the efficiency of our catalysts and signifies significant energy savings. The characterization results and theoretical calculations indicated that the superior OER/GOR performance of CoFe-MOF-74@MWCNT can be ascribed to the synergistic effect between MWCNT and the mixed metal nodes of the bimetallic organic framework. The doping of MWCNT promoted the catalyst charge transfer efficiency (Rct was only 5.56 Ω) in the OER process. The mixed metal nodes of CoFe-MOF-74@MWCNT provided more active sites for the electrocatalytic reaction, and promoted the bond-breaking of critical intermediates in the oxidation process, significantly reducing the free energy of catalytic intermediates and accelerating reaction kinetics. This work provides a strategy for designing multifunctional electrocatalysts for OER and biomass small molecule oxidation and highlights the potential for significant energy savings in practical applications.
气候危机和对绿色可持续能源的需求推动了水电解制氢技术的快速发展。阳极反应制约着水电解的效率，改进阳极反应动力学是高效制氢的关键，也是有效应对全球环境和能源挑战的关键。因此，我们重点关注阳极氧化反应动力学的改进。我们制备了多壁碳纳米管与双金属有机框架（CoFe-MOF-74）复合电催化剂（CoFe-MOF-74@MWCNT），用于 OER 和动力学上更有利的葡萄糖氧化反应（GOR）。与商用 RuO2 相比，CoFe-MOF-74@MWCNT 表现出更优越的 OER 催化性能，在电流密度为 10 mA cm-2 时，过电位（273 mV）更低，塔菲尔斜率（55 mV dec-1）更低。此外，在阳极添加葡萄糖后，10 mA cm-2 所需的电位仅为 1.291 V（与 RHE 相比），比 OER 电位降低了 212 mV。电位的降低证明了我们催化剂的效率，同时也标志着显著的节能效果。表征结果和理论计算表明，CoFe-MOF-74@MWCNT 优异的 OER/GOR 性能可归因于 MWCNT 与双金属有机框架的混合金属节点之间的协同效应。MWCNT 的掺杂提高了 OER 过程中催化剂的电荷转移效率（Rct 仅为 5.56 Ω）。CoFe-MOF-74@MWCNT 的混合金属节点为电催化反应提供了更多的活性位点，促进了氧化过程中关键中间产物的断键，显著降低了催化中间产物的自由能，加速了反应动力学。这项工作为设计用于 OER 和生物质小分子氧化的多功能电催化剂提供了一种策略，并凸显了在实际应用中显著节能的潜力。
{"title":"Construction of bifunctional MOF-based composite electrocatalysts promoting oxygen evolution reaction and glucose oxidation reaction and its kinetic deciphering","authors":"Hongmei Yuan, Changyu Weng, Xinghua Zhang, Lungang Chen, Qi Zhang, Longlong Ma, Jianguo Liu","doi":"10.1016/j.mtphys.2024.101601","DOIUrl":"https://doi.org/10.1016/j.mtphys.2024.101601","url":null,"abstract":"The climate crisis and the need for green and sustainable energy drive the rapid development of hydrogen production from water electrolysis. Improvements in the kinetics of the anode reaction, which governs the efficiency of water electrolysis, are essential for efficient hydrogen production and key to effectively addressing global environmental and energy challenges. Hence, we focus on improving the kinetics of the anode oxidation reaction. The multi-walled carbon nanotubes coupled with bimetallic organic framework (CoFe-MOF-74) composite electrocatalysts (CoFe-MOF-74@MWCNT) were fabricated for OER and the kinetically more favorable glucose oxidation reaction (GOR). Compared to commercial RuO<sub>2</sub>, CoFe-MOF-74@MWCNT showed superior OER catalytic performance, exhibiting a lower overpotential (273 mV) and a lower Tafel slope (55 mV dec<sup>-1</sup>) at a current density of 10 mA cm<sup>-2</sup>. Moreover, after adding glucose to the anode, the potential required of 10 mA cm<sup>-2</sup> was only 1.291 V (<em>vs.</em> RHE), a reduction of 212 mV compared to the OER potential. This reduction in potential demonstrates the efficiency of our catalysts and signifies significant energy savings. The characterization results and theoretical calculations indicated that the superior OER/GOR performance of CoFe-MOF-74@MWCNT can be ascribed to the synergistic effect between MWCNT and the mixed metal nodes of the bimetallic organic framework. The doping of MWCNT promoted the catalyst charge transfer efficiency (R<sub>ct</sub> was only 5.56 Ω) in the OER process. The mixed metal nodes of CoFe-MOF-74@MWCNT provided more active sites for the electrocatalytic reaction, and promoted the bond-breaking of critical intermediates in the oxidation process, significantly reducing the free energy of catalytic intermediates and accelerating reaction kinetics. This work provides a strategy for designing multifunctional electrocatalysts for OER and biomass small molecule oxidation and highlights the potential for significant energy savings in practical applications.","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"57 1","pages":""},"PeriodicalIF":11.5,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-20DOI: 10.1016/j.mtphys.2024.101600
Muhammad Tahir Sohail, Jinde Yin, Muhammad Abdullah, Muhammad Younis, Muhammad Naveed Anjum, Muhammad Tayyab Sohail, Roobaea Alroobaea, Imtiaz Ahmed, Yan Peiguang
High-power lasers operating at the 2 μm wavelength domain have gained considerable interest in recent times owing to their distinct characteristics and versatile applications in the field of medical and industrial precision processing. This article presents a comprehensive review of high-power lasers, beginning with an overview of rare-earth silica fiber as a critical component for high-power lasers performing at 2 μm. Subsequently, the research progress of three essential high-power laser technologies – continuous-wave (CW), pulsed, and single-frequency (SF) lasers – is thoroughly analyzed, highlighting their respective strengths and limitations. Moreover, the potential of combining silica fibers with Raman technology for effective wavelength extension in 2 μm lasers is explored. Furthermore, the article emphasizes the current challenges associated with the progression of high-power fiber lasers and outlines potential avenues for future advancements.
{"title":"Recent Progress on High-Power 2 μm Fiber Lasers: A Comprehensive Study of Advancements, Applications, and Future Perspectives","authors":"Muhammad Tahir Sohail, Jinde Yin, Muhammad Abdullah, Muhammad Younis, Muhammad Naveed Anjum, Muhammad Tayyab Sohail, Roobaea Alroobaea, Imtiaz Ahmed, Yan Peiguang","doi":"10.1016/j.mtphys.2024.101600","DOIUrl":"https://doi.org/10.1016/j.mtphys.2024.101600","url":null,"abstract":"High-power lasers operating at the 2 μm wavelength domain have gained considerable interest in recent times owing to their distinct characteristics and versatile applications in the field of medical and industrial precision processing. This article presents a comprehensive review of high-power lasers, beginning with an overview of rare-earth silica fiber as a critical component for high-power lasers performing at 2 μm. Subsequently, the research progress of three essential high-power laser technologies – continuous-wave (CW), pulsed, and single-frequency (SF) lasers – is thoroughly analyzed, highlighting their respective strengths and limitations. Moreover, the potential of combining silica fibers with Raman technology for effective wavelength extension in 2 μm lasers is explored. Furthermore, the article emphasizes the current challenges associated with the progression of high-power fiber lasers and outlines potential avenues for future advancements.","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"63 1","pages":""},"PeriodicalIF":11.5,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
High-entropy alloys, as a novel type of absorber, exhibit exceptional electromagnetic modulation capabilities and significant potential for electromagnetic wave absorption. In this work, the FeCoNiCrMn high-entropy alloy absorbent prepared through a mechanical alloying process demonstrates a dual-phase solid solution structure comprising face-centered cubic (FCC) and body-centered cubic (BCC) phases. By varying the manganese (Mn) content in the system, it is possible to enhance the degree of crystallinity, maintain the integrity of the crystal structure, and effectively control the relative proportion of the BCC phase within the overall phase composition. This adjustment improves the brittleness of the sheet-like particles, reduces particle size, and significantly lowers the permittivity. When the molar ratio of Mn is 0.6, the sample exhibits improved impedance matching due to the optimal permittivity and permeability. Notably, the impedance matching and attenuation constant can also be balanced. At 6.42 GHz, the FeCoNiCr0.4Mn0.6 alloy powder achieves the maximum reflection loss of −48.49 dB at a matching layer thickness of 3 mm. When the matching thickness is reduced to 2 mm, it can effectively cover a frequency range of 8.7–14.1 GHz (effective absorption bandwidth of 5.4 GHz), along with a wide absorption bandwidth and high absorption efficiency.
{"title":"Improving electromagnetic wave absorption performance by adjusting the proportion of brittle BCC phase in FeCoNiCr0.4Mnx high-entropy alloys","authors":"Yuping Duan, Meiqi Li, Guo Yuan, Ning Zhu, Huifang Pang, Chenxu Dou","doi":"10.1016/j.mtphys.2024.101596","DOIUrl":"https://doi.org/10.1016/j.mtphys.2024.101596","url":null,"abstract":"High-entropy alloys, as a novel type of absorber, exhibit exceptional electromagnetic modulation capabilities and significant potential for electromagnetic wave absorption. In this work, the FeCoNiCrMn high-entropy alloy absorbent prepared through a mechanical alloying process demonstrates a dual-phase solid solution structure comprising face-centered cubic (FCC) and body-centered cubic (BCC) phases. By varying the manganese (Mn) content in the system, it is possible to enhance the degree of crystallinity, maintain the integrity of the crystal structure, and effectively control the relative proportion of the BCC phase within the overall phase composition. This adjustment improves the brittleness of the sheet-like particles, reduces particle size, and significantly lowers the permittivity. When the molar ratio of Mn is 0.6, the sample exhibits improved impedance matching due to the optimal permittivity and permeability. Notably, the impedance matching and attenuation constant can also be balanced. At 6.42 GHz, the FeCoNiCr<sub>0.4</sub>Mn<sub>0.6</sub> alloy powder achieves the maximum reflection loss of −48.49 dB at a matching layer thickness of 3 mm. When the matching thickness is reduced to 2 mm, it can effectively cover a frequency range of 8.7–14.1 GHz (effective absorption bandwidth of 5.4 GHz), along with a wide absorption bandwidth and high absorption efficiency.","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"248 1","pages":""},"PeriodicalIF":11.5,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-17DOI: 10.1016/j.mtphys.2024.101588
Yaling Wang, Yue Sun, Wenqiang Li, Pan Li, Jing Wang, Pengcheng Zhu, Shiyang Qi, Jihua Tang, Yuan Deng
Flexible temperature-pressure bimodal sensing arrays can detect multiple types of information, including force and heat, making them crucial for applications such as object classification, human-machine interaction, and artificial intelligence. However, current sensors primarily focus on single-parameter and single-point measurements, while lacking a continuous and stable power supply. This study developed flexible, self-powered temperature-pressure sensing arrays by integrating a stepped microcone structure with thermoelectric materials. This stepped distribution microstructure design enabled effective pressure measurements across a wide range, with high sensitivity and fast response. Temperature-independent measurements were achieved synchronously over a wide temperature range (35-173 °C) by incorporating high-performance Bi2Te3-based thermoelectric films. These temperature and pressure sensing units can discern temperature and pressure stimuli without mutual interference. Furthermore, with the assistance of deep learning, these bimodal sensing arrays performed spatial mapping of temperature and pressure simultaneously, demonstrating their ability to identify different types of objects with an accuracy exceeding 98%. Therefore, this study shows promise for advancing human-machine interaction, artificial intelligence, and self-powered electronic skins.
{"title":"Self-powered temperature pressure sensing arrays with stepped microcone structure and Bi2Te3-based films for deep learning-assisted object recognition","authors":"Yaling Wang, Yue Sun, Wenqiang Li, Pan Li, Jing Wang, Pengcheng Zhu, Shiyang Qi, Jihua Tang, Yuan Deng","doi":"10.1016/j.mtphys.2024.101588","DOIUrl":"https://doi.org/10.1016/j.mtphys.2024.101588","url":null,"abstract":"Flexible temperature-pressure bimodal sensing arrays can detect multiple types of information, including force and heat, making them crucial for applications such as object classification, human-machine interaction, and artificial intelligence. However, current sensors primarily focus on single-parameter and single-point measurements, while lacking a continuous and stable power supply. This study developed flexible, self-powered temperature-pressure sensing arrays by integrating a stepped microcone structure with thermoelectric materials. This stepped distribution microstructure design enabled effective pressure measurements across a wide range, with high sensitivity and fast response. Temperature-independent measurements were achieved synchronously over a wide temperature range (35-173 °C) by incorporating high-performance Bi<sub>2</sub>Te<sub>3</sub>-based thermoelectric films. These temperature and pressure sensing units can discern temperature and pressure stimuli without mutual interference. Furthermore, with the assistance of deep learning, these bimodal sensing arrays performed spatial mapping of temperature and pressure simultaneously, demonstrating their ability to identify different types of objects with an accuracy exceeding 98%. Therefore, this study shows promise for advancing human-machine interaction, artificial intelligence, and self-powered electronic skins.","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"13 1","pages":""},"PeriodicalIF":11.5,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-16DOI: 10.1016/j.mtphys.2024.101597
Xingchen Ma, Yi Qin, Lian Zhou, Qianqian Hu, Xinhao Xiang, Heinz von Seggern, Sergey Zhukov, Alexander A. Altmann, Mario Kupnik, Wenxin Niu, Xiaoqing Zhang
In view of the global ecosystem crisis resulting from the ubiquitous electronic waste (e- and plastic waste), the engineering of advanced electronic devices from sustainable materials is gaining considerable attention. Nevertheless, the development of advanced, maybe even degradable electronics with comparable or even improved functionality remains a great challenge. In this article a fabrication process for a fully degradable, highly sensitive pressure sensor based on electrets is proposed enabling the creation of a universal platform for monitoring various biomechanical signals. The high sensitivity of the proposed biomechanical electret-based sensor utilizes electrostatic induction of highly deformable cellular polylactic acid (PLA) films with a serrated ripple structure and an improved bipolar charge storage capability. This biodegradable pressure sensor possesses competitive mechanical signal detection performance, obtaining a high pressure sensitivity (10 V/kPa), robust working stability (∼30,000 continuous cycles), short electromechanical response/recovery time (∼17 ms), and satisfactory heat resistance up to 60 °C. By tailoring the thickness of the encapsulation layer, the functional lifetime of the biomechanical sensor in physiological environment can be controlled effectively, facilitating adaptability to various implantable application scenarios. Altogether, the present work not only proposes an effective fabrication process for high-performance pressure sensors, but also provides new insight into the design of sustainable electronics with controllable lifetime thereby minimizing their environmental footprint. The developed sensor promises great potential in monitoring multiple biomechanical signals inside and outside the human body (e.g., body movements and physiological activities) as well as an environment-friendly realization of green electronics.
{"title":"Fully Degradable, Highly Sensitive Pressure Sensor Based on Bipolar Electret for Biomechanical Signal Monitoring","authors":"Xingchen Ma, Yi Qin, Lian Zhou, Qianqian Hu, Xinhao Xiang, Heinz von Seggern, Sergey Zhukov, Alexander A. Altmann, Mario Kupnik, Wenxin Niu, Xiaoqing Zhang","doi":"10.1016/j.mtphys.2024.101597","DOIUrl":"https://doi.org/10.1016/j.mtphys.2024.101597","url":null,"abstract":"In view of the global ecosystem crisis resulting from the ubiquitous electronic waste (e- and plastic waste), the engineering of advanced electronic devices from sustainable materials is gaining considerable attention. Nevertheless, the development of advanced, maybe even degradable electronics with comparable or even improved functionality remains a great challenge. In this article a fabrication process for a fully degradable, highly sensitive pressure sensor based on electrets is proposed enabling the creation of a universal platform for monitoring various biomechanical signals. The high sensitivity of the proposed biomechanical electret-based sensor utilizes electrostatic induction of highly deformable cellular polylactic acid (PLA) films with a serrated ripple structure and an improved bipolar charge storage capability. This biodegradable pressure sensor possesses competitive mechanical signal detection performance, obtaining a high pressure sensitivity (10 V/kPa), robust working stability (∼30,000 continuous cycles), short electromechanical response/recovery time (∼17 ms), and satisfactory heat resistance up to 60 °C. By tailoring the thickness of the encapsulation layer, the functional lifetime of the biomechanical sensor in physiological environment can be controlled effectively, facilitating adaptability to various implantable application scenarios. Altogether, the present work not only proposes an effective fabrication process for high-performance pressure sensors, but also provides new insight into the design of sustainable electronics with controllable lifetime thereby minimizing their environmental footprint. The developed sensor promises great potential in monitoring multiple biomechanical signals inside and outside the human body (e.g., body movements and physiological activities) as well as an environment-friendly realization of green electronics.","PeriodicalId":18253,"journal":{"name":"Materials Today Physics","volume":"21 1","pages":""},"PeriodicalIF":11.5,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142642742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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