Minseon Gu, Keun Wook Lee, Beomjin Park, Beom Soo Joo, Young Jun Chang, Dong-Wook Park, Moonsup Han
Hybrid 2D/0D structures with various 2D materials and 0D quantum dots (QDs) have been studied to overcome the limitations of 2D materials. In this work, a hybrid structure with MoS2 and silicon quantum dots (Si QDs) as a photodetector is developed. The I–V transfer characteristics show a threshold voltage shift after decorating Si QDs on MoS2, which results from an n‐type doping effect to the MoS2 channel from the Si QDs. The field‐effect mobility of the MoS2/Si QDs device is increased by ≈5.8 times compared with that of the bare MoS2 device. It is understood that the mobility enhancement is attributed to the surface defect passivation of MoS2 at the interface with Si QDs. It is observed that the photoresponsivity of the MoS2/Si QDs structure is improved by ≈7.7 times compared with that of the bare MoS2 device under 500 nm illumination. Additionally, it is observed that the photoluminescence (PL) intensity of MoS2 is increased about 4.5 times after decoration of Si QDs. The band alignment as type I at the interface between the Si QDs and MoS2 is interpreted. The mobility enhancement and the photoexcited charge transfer (CT) between the MoS2 and the Si QDs due to the illumination lead to enhancing the photoresponsivity of the MoS2/Si QDs hybrid structure.
{"title":"Photoresponsivity Enhancement of Monolayer MoS2 by Silicon Quantum Dots","authors":"Minseon Gu, Keun Wook Lee, Beomjin Park, Beom Soo Joo, Young Jun Chang, Dong-Wook Park, Moonsup Han","doi":"10.1002/pssr.202300220","DOIUrl":"https://doi.org/10.1002/pssr.202300220","url":null,"abstract":"Hybrid 2D/0D structures with various 2D materials and 0D quantum dots (QDs) have been studied to overcome the limitations of 2D materials. In this work, a hybrid structure with MoS2 and silicon quantum dots (Si QDs) as a photodetector is developed. The I–V transfer characteristics show a threshold voltage shift after decorating Si QDs on MoS2, which results from an n‐type doping effect to the MoS2 channel from the Si QDs. The field‐effect mobility of the MoS2/Si QDs device is increased by ≈5.8 times compared with that of the bare MoS2 device. It is understood that the mobility enhancement is attributed to the surface defect passivation of MoS2 at the interface with Si QDs. It is observed that the photoresponsivity of the MoS2/Si QDs structure is improved by ≈7.7 times compared with that of the bare MoS2 device under 500 nm illumination. Additionally, it is observed that the photoluminescence (PL) intensity of MoS2 is increased about 4.5 times after decoration of Si QDs. The band alignment as type I at the interface between the Si QDs and MoS2 is interpreted. The mobility enhancement and the photoexcited charge transfer (CT) between the MoS2 and the Si QDs due to the illumination lead to enhancing the photoresponsivity of the MoS2/Si QDs hybrid structure.","PeriodicalId":20059,"journal":{"name":"physica status solidi (RRL) – Rapid Research Letters","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81764581","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}
G. Ermolaev, Ying Xie, Liu Qian, Mikhail K. Tatmyshevskiy, A. Slavich, Aleksey Arsenin, Jin Zhang, V. Volkov, A. Chernov
Two‐dimensional materials are the fundamental building blocks for modern optoelectronics and photonics. Optically anisotropic monolayers give even more flexibility in device design and performance. However, the random orientation of optical axes in the large‐scale samples prevents anisotropic monolayers from widespread use. The alternative structure is a monolayer of aligned single‐walled carbon nanotubes (SWCNTs) with an anisotropic dielectric tensor. Here, we measure aligned SWCNTs monolayer anisotropic optical constants in a broad spectral range (250 – 1700 nm) for the first time. We discovered that it has a large birefringence of Δn ∽ 0.2 and a high dichroism of Δk ∽ 0.4. Moreover, we demonstrated that aligned SWCNTs monolayer optical response could be described by an effective medium approximation using the graphene dielectric function. Besides, it gives a universal approach for a determination of carbon concentration in nanotubes structures. It also applies for other types of carbon nanotubes, such as multi‐walled and randomly oriented carbon nanotubes arrays. Hence, our results add aligned SWCNTs monolayer optical constants to the optical anisotropy database, which facilitates the longstanding challenge of using one‐dimensional structures in two dimensions, and provide a rapid characterization method for carbon nanotubes.This article is protected by copyright. All rights reserved.
{"title":"Anisotropic optical properties of monolayer aligned single‐walled carbon nanotubes","authors":"G. Ermolaev, Ying Xie, Liu Qian, Mikhail K. Tatmyshevskiy, A. Slavich, Aleksey Arsenin, Jin Zhang, V. Volkov, A. Chernov","doi":"10.1002/pssr.202300199","DOIUrl":"https://doi.org/10.1002/pssr.202300199","url":null,"abstract":"Two‐dimensional materials are the fundamental building blocks for modern optoelectronics and photonics. Optically anisotropic monolayers give even more flexibility in device design and performance. However, the random orientation of optical axes in the large‐scale samples prevents anisotropic monolayers from widespread use. The alternative structure is a monolayer of aligned single‐walled carbon nanotubes (SWCNTs) with an anisotropic dielectric tensor. Here, we measure aligned SWCNTs monolayer anisotropic optical constants in a broad spectral range (250 – 1700 nm) for the first time. We discovered that it has a large birefringence of Δn ∽ 0.2 and a high dichroism of Δk ∽ 0.4. Moreover, we demonstrated that aligned SWCNTs monolayer optical response could be described by an effective medium approximation using the graphene dielectric function. Besides, it gives a universal approach for a determination of carbon concentration in nanotubes structures. It also applies for other types of carbon nanotubes, such as multi‐walled and randomly oriented carbon nanotubes arrays. Hence, our results add aligned SWCNTs monolayer optical constants to the optical anisotropy database, which facilitates the longstanding challenge of using one‐dimensional structures in two dimensions, and provide a rapid characterization method for carbon nanotubes.This article is protected by copyright. All rights reserved.","PeriodicalId":20059,"journal":{"name":"physica status solidi (RRL) – Rapid Research Letters","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89739992","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}
Once again, it is our great pleasure to continue the EPCOS tradition by presenting this fourth edition of the special issue on Phase-Change and Ovonic Materials that is published each year as part of the European Symposium on Phase-Change and Ovonic Sciences (EPCOS). We have to admit that the 2022 edition of EPCOS had a special spirit as it marked the long-awaited return to a face-to-face on-site symposium after a two-year hiatus due to the Covid crisis. Last September, the 2022 edition of EPCOS was the most successful in terms of attendance in the history of EPCOS. This is no coincidence and once again, in this editorial, Harish Bhaskaran, Luci Bywater and the Oxford team are sincerely thanked on behalf of the entire EPCOS community for making this success possible even if unfortunately, some of the EPCOS major actors could not join us at the Wolfson College in Oxford this year. As in the three previous editions, this special issue again aims to summarize recent and innovative scientific and technological achievements in the field of phase-change materials, as well as their possible new fields of application. In addition to recent advances in this field, the objective is also to present emerging interests in neuromorphic computing, phase-change and nonlinear photonics or plasmonics. This special issue thus provides an overview of the state of the art, both experimental and theoretical, for experienced and young researchers interested in these topics. As usual, let us first recall, for the younger and newer members of our ever-evolving community, that EPCOS was born in Switzerland in 2001, with the aim to provide a platform to discuss and promote the fundamental science of phase-change materials (PCM). This goal also included their applications in rewritable optical discs (e.g., first with CDs and later with the successfully developed DVD and Blu-ray Disc formats) and thus initially PCOS referred to phase-change optical storage (which was diversified in 2005 to phase-change and ovonic science). In fact, EPCOS was born from the first PCOS symposium held in Japan in 1990, thanks to Professor Masahiro Okuda, who was the advisor of EPCOS during its early years. In recent years, the field has diversified considerably. While the scientific and technological fingerprints of the field’s founding father, the late Stanford Ovshinsky, are still very recognizable, the number of topics covered has continued to grow significantly with applications including non-volatile electronic memories, optoelectronics, photonics, and neuromorphic computing. The 2022 edition of EPCOS has confirmed that EPCOS is the premier international conference on this exciting and evergreen topic. This 2022 edition, which follows the 2021 virtual edition, was somewhat of a challenge for the EPCOS community. However, its unprecedented success confirmed the close ties between key players in the field, both academic and industrial. By again covering a rich variety of topics beyond phase-c
再一次，我们非常高兴能够延续EPCOS的传统，推出第四版相变和椭圆材料特刊，该特刊每年出版一次，作为欧洲相变和椭圆科学研讨会(EPCOS)的一部分。不得不承认，2022年的EPCOS，在因新冠疫情中断两年之后，终于回到了面对面的现场研讨会，这是一种特殊的精神。去年9月，2022年的EPCOS是EPCOS历史上出席人数最多的一届。这并非巧合，在这篇社论中，我再次代表整个EPCOS社区衷心感谢Harish Bhaskaran、Luci Bywater和牛津团队，尽管不幸的是，今年EPCOS的一些主要参与者无法参加牛津大学沃尔夫森学院的活动。与前三版一样，本期特刊再次旨在总结相变材料领域的最新和创新科技成果，以及它们可能的新应用领域。除了这一领域的最新进展外，会议的目标还包括展示神经形态计算、相变和非线性光子学或等离子体学方面的新兴兴趣。因此，这一期特刊为对这些主题感兴趣的有经验和年轻的研究人员提供了对实验和理论两方面的艺术状态的概述。与往常一样，让我们首先回顾一下，对于我们不断发展的社区的年轻和新成员，EPCOS于2001年在瑞士诞生，旨在提供一个讨论和促进相变材料(PCM)基础科学的平台。这一目标还包括它们在可重写光盘中的应用(例如，首先是cd，后来是成功开发的DVD和蓝光光盘格式)，因此最初的PCOS指的是相变光学存储(在2005年多样化到相变和电子科学)。事实上，EPCOS诞生于1990年在日本举行的第一届PCOS研讨会，这要归功于EPCOS早期的顾问Masahiro Okuda教授。近年来，该领域已相当多样化。虽然该领域的创始人，已故的斯坦福·奥夫辛斯基的科学和技术指纹仍然非常清晰，但所涵盖的主题数量继续显著增长，应用包括非易失性电子存储器，光电子学，光子学和神经形态计算。2022年的EPCOS已经证实，EPCOS是这一令人兴奋和常青主题的首要国际会议。继2021年的虚拟版之后，2022年的版本对EPCOS社区来说是一个挑战。然而，它前所未有的成功证实了学术界和工业界关键参与者之间的密切联系。通过再次涵盖相变存储器以外的丰富多样的主题，第四期特刊将再次标志着EPCOS的历史。Park等人关于使用Sb2Te3/TiTe2异质结构取代传统和规范的GST (Ge2Sb2Te5)合金用于存储级存储器和神经形态计算硬件的论文是第一个例子[pssr.202200451]。事实上，对于这些最近推出的新型相变存储器(PCM)应用，需要比通常的GST225合金获得的更快的SET速度和更低的RESET能量。在本研究中，基于溅射沉积的非晶Sb2Te3和TiTe2纳米层的多层PCM器件显示出快速的SET速度(30 ns)，与基于gst的参考PCM相比，RESET能量降低了80%以上，并且在高电阻状态下电阻漂移也更低。这些非常有希望的结果值得未来的社区工作，例如评估这种新型异质结构在编程周期中的耐久性。类似的目标也激励了Kashem等人提出的工作。[202200419]，他们提出了结合非晶化结晶动力学和电热效应的有限元模拟框架，以更好地描述PCM纳米级器件的RESET-SET-READ操作。他们的结论是，基于GST合金的模型可以解释器件运行过程中结晶度动态变化的影响，并且他们的结果与实验观察结果一致，从而更好地理解器件动力学。该模型将允许研究任何器件几何形状，以探索编程脉冲和材料工程以及器件结构对器件性能的影响。例如，模拟结果预测了热电效应对RESET电流要求的影响，以及加热器高度对热损失和RESET电流的重要作用。 存储级存储器应用的PCM技术的另一个挑战是通过使用多层单元(mlc)来提高存储密度，如Zhao等人所示。P. no<s:1>大学格勒诺布尔阿尔卑斯CEA, Leti F-38000格勒诺布尔，法国E-mail: pierre.noe@cea.fr格罗宁根大学尼延堡4,NL-9747 AG格罗宁根，荷兰M. Wuttig I.物理研究所(IA)德国亚琛工业大学Sommerfeldstraße, 52074亚琛，德国M. Wuttig jra - Institute Green IT jra - fit Forschungszentrum j<s:1>利希有限公司和亚琛工业大学52056亚琛
{"title":"Phase‐Change and Ovonic Materials (Fourth Edition)","authors":"P. Noé, B. Kooi, M. Wuttig","doi":"10.1002/pssr.202300129","DOIUrl":"https://doi.org/10.1002/pssr.202300129","url":null,"abstract":"Once again, it is our great pleasure to continue the EPCOS tradition by presenting this fourth edition of the special issue on Phase-Change and Ovonic Materials that is published each year as part of the European Symposium on Phase-Change and Ovonic Sciences (EPCOS). We have to admit that the 2022 edition of EPCOS had a special spirit as it marked the long-awaited return to a face-to-face on-site symposium after a two-year hiatus due to the Covid crisis. Last September, the 2022 edition of EPCOS was the most successful in terms of attendance in the history of EPCOS. This is no coincidence and once again, in this editorial, Harish Bhaskaran, Luci Bywater and the Oxford team are sincerely thanked on behalf of the entire EPCOS community for making this success possible even if unfortunately, some of the EPCOS major actors could not join us at the Wolfson College in Oxford this year. As in the three previous editions, this special issue again aims to summarize recent and innovative scientific and technological achievements in the field of phase-change materials, as well as their possible new fields of application. In addition to recent advances in this field, the objective is also to present emerging interests in neuromorphic computing, phase-change and nonlinear photonics or plasmonics. This special issue thus provides an overview of the state of the art, both experimental and theoretical, for experienced and young researchers interested in these topics. As usual, let us first recall, for the younger and newer members of our ever-evolving community, that EPCOS was born in Switzerland in 2001, with the aim to provide a platform to discuss and promote the fundamental science of phase-change materials (PCM). This goal also included their applications in rewritable optical discs (e.g., first with CDs and later with the successfully developed DVD and Blu-ray Disc formats) and thus initially PCOS referred to phase-change optical storage (which was diversified in 2005 to phase-change and ovonic science). In fact, EPCOS was born from the first PCOS symposium held in Japan in 1990, thanks to Professor Masahiro Okuda, who was the advisor of EPCOS during its early years. In recent years, the field has diversified considerably. While the scientific and technological fingerprints of the field’s founding father, the late Stanford Ovshinsky, are still very recognizable, the number of topics covered has continued to grow significantly with applications including non-volatile electronic memories, optoelectronics, photonics, and neuromorphic computing. The 2022 edition of EPCOS has confirmed that EPCOS is the premier international conference on this exciting and evergreen topic. This 2022 edition, which follows the 2021 virtual edition, was somewhat of a challenge for the EPCOS community. However, its unprecedented success confirmed the close ties between key players in the field, both academic and industrial. By again covering a rich variety of topics beyond phase-c","PeriodicalId":20059,"journal":{"name":"physica status solidi (RRL) – Rapid Research Letters","volume":"122 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76740347","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}
D. S. Assi, Hongli Huang, Kadir Ufuk Kandira, Nasser S. Alsulaiman, Vaskuri C. S. Theja, Hasan T. Abbas, V. Karthikeyan, Vellaisamy A. L. Roy
In the realm of artificial intelligence, ultrahigh‐performance neuromorphic computing plays a significant role in executing multiple complex operations in parallel while adhering to a more biologically plausible model. Despite their importance, developing an artificial synaptic device to match the human brain's efficiency is an extremely complex task involving high energy consumption and poor parallel processing latency. Herein, a simple molecule, copper‐iodide‐based artificial synaptic device demonstrating core synaptic functions of human neural networks is introduced. Exceptionally high carrier mobility and dielectric constant in the developed device lead to superior efficacies in neuromorphic characteristics with ultrahigh paired‐pusle facilitation index (>195). The results demonstrate biomimetic capabilities that exert a direct influence on neural networks across multiple timescales, ranging from short‐ to long‐term memory. This flexible reconfiguration of neural excitability provided by the copper‐iodide‐based synaptic device positions it as a promising candidate for creating advanced artificial intelligence systems.
{"title":"Charge‐Mediated Copper‐Iodide‐Based Artificial Synaptic Device with Ultrahigh Neuromorphic Efficacy","authors":"D. S. Assi, Hongli Huang, Kadir Ufuk Kandira, Nasser S. Alsulaiman, Vaskuri C. S. Theja, Hasan T. Abbas, V. Karthikeyan, Vellaisamy A. L. Roy","doi":"10.1002/pssr.202300191","DOIUrl":"https://doi.org/10.1002/pssr.202300191","url":null,"abstract":"In the realm of artificial intelligence, ultrahigh‐performance neuromorphic computing plays a significant role in executing multiple complex operations in parallel while adhering to a more biologically plausible model. Despite their importance, developing an artificial synaptic device to match the human brain's efficiency is an extremely complex task involving high energy consumption and poor parallel processing latency. Herein, a simple molecule, copper‐iodide‐based artificial synaptic device demonstrating core synaptic functions of human neural networks is introduced. Exceptionally high carrier mobility and dielectric constant in the developed device lead to superior efficacies in neuromorphic characteristics with ultrahigh paired‐pusle facilitation index (>195). The results demonstrate biomimetic capabilities that exert a direct influence on neural networks across multiple timescales, ranging from short‐ to long‐term memory. This flexible reconfiguration of neural excitability provided by the copper‐iodide‐based synaptic device positions it as a promising candidate for creating advanced artificial intelligence systems.","PeriodicalId":20059,"journal":{"name":"physica status solidi (RRL) – Rapid Research Letters","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91284293","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}
Jia Liang, Yingchao Yang, Jing Zhang, Pei Dong, J. Lou
{"title":"Ultrasmall CoSe2 Nanoparticles Grown on MoS2 Nanofilms: A New Catalyst for Hydrogen Evolution Reaction","authors":"Jia Liang, Yingchao Yang, Jing Zhang, Pei Dong, J. Lou","doi":"10.1002/pssr.202300169","DOIUrl":"https://doi.org/10.1002/pssr.202300169","url":null,"abstract":"","PeriodicalId":20059,"journal":{"name":"physica status solidi (RRL) – Rapid Research Letters","volume":"64 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77631962","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}
A. Markhabayeva, Anarova S. Assiya, Abdullin A. Khabibulla, Kalkozova K. Zhanar, Tulegenova T. Aida, N. Nuraje
{"title":"A hybrid supercapacitor from nickel cobalt sulfide and activated carbon for energy storage application","authors":"A. Markhabayeva, Anarova S. Assiya, Abdullin A. Khabibulla, Kalkozova K. Zhanar, Tulegenova T. Aida, N. Nuraje","doi":"10.1002/pssr.202300211","DOIUrl":"https://doi.org/10.1002/pssr.202300211","url":null,"abstract":"","PeriodicalId":20059,"journal":{"name":"physica status solidi (RRL) – Rapid Research Letters","volume":"68 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91164122","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}
{"title":"Synthesis of Calcium Manganese Oxide Films Using a Sol‐Gel Method and Evaluation of Color and Photocatalytic Properties","authors":"Ryohei Oka, T. Hayakawa","doi":"10.1002/pssr.202300233","DOIUrl":"https://doi.org/10.1002/pssr.202300233","url":null,"abstract":"","PeriodicalId":20059,"journal":{"name":"physica status solidi (RRL) – Rapid Research Letters","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80641149","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}
A. Bhuiyan, Lingyu Meng, Hsien-Lien Huang, C. Chae, Jinwoo Hwang, Hongping Zhao
Growths of monoclinic (AlxGa1−x)2O3 thin films up to 99% Al contents are demonstrated via metalorganic chemical vapor deposition (MOCVD) using trimethylgallium (TMGa) as the Ga precursor. The utilization of TMGa, rather than triethylgallium, enables a significant improvement of the growth rates (>2.5 μm h−1) of β‐(AlxGa1−x)2O3 thin films on (010), (100), and ( 2¯ 01) β‐Ga2O3 substrates. By systematically tuning the precursor molar flow rates, growth of coherently strained phase pure β‐(AlxGa1−x)2O3 films is demonstrated by comprehensive material characterizations via high‐resolution X‐ray diffraction (XRD) and atomic‐resolution scanning transmission electron microscopy (STEM) imaging. Monoclinic (AlxGa1−x)2O3 films with Al contents up to 99, 29, and 16% are achieved on (100), (010), and ( 2¯ 01) β‐Ga2O3 substrates, respectively. Beyond 29% of Al incorporation, the (010) (AlxGa1−x)2O3 films exhibit β‐ to γ‐phase segregation. β‐(AlxGa1−x)2O3 films grown on ( 2¯ 01) β‐Ga2O3 show local segregation of Al along (100) plane. Record‐high Al incorporations up to 99% in monoclinic (AlxGa1−x)2O3 grown on (100) Ga2O3 are confirmed from XRD, STEM, electron nanodiffraction, and X‐ray photoelectron spectroscopy measurements. These results indicate great promises of MOCVD development of β‐(AlxGa1−x)2O3 films and heterostructures with high Al content and growth rates using TMGa for next‐generation high‐power and high‐frequency electronic devices.
{"title":"Al Incorporation up to 99% in Metalorganic Chemical Vapor Deposition‐Grown Monoclinic (AlxGa1–x)2O3 Films Using Trimethylgallium","authors":"A. Bhuiyan, Lingyu Meng, Hsien-Lien Huang, C. Chae, Jinwoo Hwang, Hongping Zhao","doi":"10.1002/pssr.202300224","DOIUrl":"https://doi.org/10.1002/pssr.202300224","url":null,"abstract":"Growths of monoclinic (AlxGa1−x)2O3 thin films up to 99% Al contents are demonstrated via metalorganic chemical vapor deposition (MOCVD) using trimethylgallium (TMGa) as the Ga precursor. The utilization of TMGa, rather than triethylgallium, enables a significant improvement of the growth rates (>2.5 μm h−1) of β‐(AlxGa1−x)2O3 thin films on (010), (100), and ( 2¯ 01) β‐Ga2O3 substrates. By systematically tuning the precursor molar flow rates, growth of coherently strained phase pure β‐(AlxGa1−x)2O3 films is demonstrated by comprehensive material characterizations via high‐resolution X‐ray diffraction (XRD) and atomic‐resolution scanning transmission electron microscopy (STEM) imaging. Monoclinic (AlxGa1−x)2O3 films with Al contents up to 99, 29, and 16% are achieved on (100), (010), and ( 2¯ 01) β‐Ga2O3 substrates, respectively. Beyond 29% of Al incorporation, the (010) (AlxGa1−x)2O3 films exhibit β‐ to γ‐phase segregation. β‐(AlxGa1−x)2O3 films grown on ( 2¯ 01) β‐Ga2O3 show local segregation of Al along (100) plane. Record‐high Al incorporations up to 99% in monoclinic (AlxGa1−x)2O3 grown on (100) Ga2O3 are confirmed from XRD, STEM, electron nanodiffraction, and X‐ray photoelectron spectroscopy measurements. These results indicate great promises of MOCVD development of β‐(AlxGa1−x)2O3 films and heterostructures with high Al content and growth rates using TMGa for next‐generation high‐power and high‐frequency electronic devices.","PeriodicalId":20059,"journal":{"name":"physica status solidi (RRL) – Rapid Research Letters","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73235827","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}
S. Panasci, I. Deretzis, E. Schilirò, A. La Magna, F. Roccaforte, A. Koos, B. Pécz, S. Agnello, M. Cannas, F. Giannazzo
The interface structure and electronic properties of monolayer (1L) MoS2 domains grown by chemical vapor deposition on 4H–SiC(0001) are investigated by microscopic/spectroscopic analyses combined with ab initio calculations. The triangular domains are epitaxially oriented on the (0001) basal plane, with the presence of a van der Waals (vdW) gap between 1L–MoS2 and the SiC terraces. The high crystalline quality of the domains is confirmed by photoluminescence emission. Furthermore, a very low tensile strain (ε ≈ 0.03%) of 1L–MoS2, consistent with the small in‐plane lattice mismatch, and a p‐type doping of (0.45 ± 0.11) × 1013 cm−2, is evaluated by Raman mapping. Density functional theory (DFT) calculations of the MoS2/4H–SiC(0001) system are also performed, considering different levels of refinement of the model: 1) the simple case of the junction between Si‐terminated SiC and MoS2, showing a covalent bond between the Si–S atoms and n‐type doping of MoS2; 2) the complete passivation of Si dangling bonds with a monolayer (1 ML) of oxygen atoms, resulting in a vdW bond with dSi–S ≈ 3.84 Å bond length and p‐type doping of MoS2; and 3) partial (¼ ML and ½ ML) oxygen coverages of the 4H–SiC surface, resulting in intermediate values of dSi–S and doping behavior.
{"title":"Interface Structure and Doping of Chemical Vapor Deposition‐Grown MoS2 on 4H–SiC by Microscopic Analyses and Ab Initio Calculations","authors":"S. Panasci, I. Deretzis, E. Schilirò, A. La Magna, F. Roccaforte, A. Koos, B. Pécz, S. Agnello, M. Cannas, F. Giannazzo","doi":"10.1002/pssr.202300218","DOIUrl":"https://doi.org/10.1002/pssr.202300218","url":null,"abstract":"The interface structure and electronic properties of monolayer (1L) MoS2 domains grown by chemical vapor deposition on 4H–SiC(0001) are investigated by microscopic/spectroscopic analyses combined with ab initio calculations. The triangular domains are epitaxially oriented on the (0001) basal plane, with the presence of a van der Waals (vdW) gap between 1L–MoS2 and the SiC terraces. The high crystalline quality of the domains is confirmed by photoluminescence emission. Furthermore, a very low tensile strain (ε ≈ 0.03%) of 1L–MoS2, consistent with the small in‐plane lattice mismatch, and a p‐type doping of (0.45 ± 0.11) × 1013 cm−2, is evaluated by Raman mapping. Density functional theory (DFT) calculations of the MoS2/4H–SiC(0001) system are also performed, considering different levels of refinement of the model: 1) the simple case of the junction between Si‐terminated SiC and MoS2, showing a covalent bond between the Si–S atoms and n‐type doping of MoS2; 2) the complete passivation of Si dangling bonds with a monolayer (1 ML) of oxygen atoms, resulting in a vdW bond with dSi–S ≈ 3.84 Å bond length and p‐type doping of MoS2; and 3) partial (¼ ML and ½ ML) oxygen coverages of the 4H–SiC surface, resulting in intermediate values of dSi–S and doping behavior.","PeriodicalId":20059,"journal":{"name":"physica status solidi (RRL) – Rapid Research Letters","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88284748","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 present study deals with the effect of adding different fillers (semiconductor and insulator) on a polystyrene (PS)/poly‐methyl methacrylate (PMMA) polymer blend using casting method. A constant content (1 wt%) of semiconductors [multiwalled carbon nanotubes (MWCNTs), polyaniline (PANI), zinc oxide nanoparticles (NPs), and titanium dioxide NPs] and insulator [silicon dioxide NPs] fillers is used. Transmission electron microscopy images for MWCNTs show that most nanotubes have an average diameter of 7–11 nm. Moreover, the average size of all metal nano‐oxides is almost 20 nm and confirmed by X‐ray diffraction. Fourier‐transform infrared spectroscopy confirms the formation and the interaction between PS/PMMA polymer blend and fillers. The structural, mechanical, optical, and dielectric properties of the prepared polymer nanocomposites are studied using different tools. Optical characteristics such as absorbance, reflection, bandgap energy (E g), and optical dielectric components (real and imaginary) are studied. These results reveal that pure 20PS/80PMMA film has E g(direct) = 4.46 eV, which drops as different fillers are incorporated into the blend. The addition of MWCNTs, PANI to the PS/PMMA blend improves the electrical conductivity due to the growth of conductive paths between the filler and the blending matrix.
{"title":"Optical and Electrical Properties of Polystyrene/Poly‐methyl methacrylate Polymeric Blend Filled with Semiconductor and Insulator Nanofillers","authors":"A. El-Gamal","doi":"10.1002/pssr.202300145","DOIUrl":"https://doi.org/10.1002/pssr.202300145","url":null,"abstract":"The present study deals with the effect of adding different fillers (semiconductor and insulator) on a polystyrene (PS)/poly‐methyl methacrylate (PMMA) polymer blend using casting method. A constant content (1 wt%) of semiconductors [multiwalled carbon nanotubes (MWCNTs), polyaniline (PANI), zinc oxide nanoparticles (NPs), and titanium dioxide NPs] and insulator [silicon dioxide NPs] fillers is used. Transmission electron microscopy images for MWCNTs show that most nanotubes have an average diameter of 7–11 nm. Moreover, the average size of all metal nano‐oxides is almost 20 nm and confirmed by X‐ray diffraction. Fourier‐transform infrared spectroscopy confirms the formation and the interaction between PS/PMMA polymer blend and fillers. The structural, mechanical, optical, and dielectric properties of the prepared polymer nanocomposites are studied using different tools. Optical characteristics such as absorbance, reflection, bandgap energy (E g), and optical dielectric components (real and imaginary) are studied. These results reveal that pure 20PS/80PMMA film has E g(direct) = 4.46 eV, which drops as different fillers are incorporated into the blend. The addition of MWCNTs, PANI to the PS/PMMA blend improves the electrical conductivity due to the growth of conductive paths between the filler and the blending matrix.","PeriodicalId":20059,"journal":{"name":"physica status solidi (RRL) – Rapid Research Letters","volume":"157 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84946592","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：