Pub Date : 2024-02-27DOI: 10.1038/s41699-024-00449-w
Mickael L. Perrin, Anooja Jayaraj, Bhaskar Ghawri, Kenji Watanabe, Takashi Taniguchi, Daniele Passerone, Michel Calame, Jian Zhang
Twisted van der Waals heterostructures have recently emerged as a versatile platform for engineering interaction-driven, topological phenomena with a high degree of control and tunability. Since the initial discovery of correlated phases in twisted bilayer graphene, a wide range of moiré materials have emerged with fascinating electronic properties. While the field of twistronics has rapidly evolved and now includes a range of multi-layered systems, moiré systems comprised of double trilayer graphene remain elusive. Here, we report electrical transport measurements combined with tight-binding calculations in twisted double trilayer graphene (TDTLG). We demonstrate that small-angle TDTLG (~1.7−2.0∘) exhibits an intrinsic bandgap at the charge neutrality point. Moreover, by tuning the displacement field, we observe a continuous insulator-semimetal-insulator transition at the CNP, which is also captured by tight-binding calculations. These results establish TDTLG systems as a highly tunable platform for further exploration of magneto-transport and optoelectronic properties.
{"title":"Electric field tunable bandgap in twisted double trilayer graphene","authors":"Mickael L. Perrin, Anooja Jayaraj, Bhaskar Ghawri, Kenji Watanabe, Takashi Taniguchi, Daniele Passerone, Michel Calame, Jian Zhang","doi":"10.1038/s41699-024-00449-w","DOIUrl":"10.1038/s41699-024-00449-w","url":null,"abstract":"Twisted van der Waals heterostructures have recently emerged as a versatile platform for engineering interaction-driven, topological phenomena with a high degree of control and tunability. Since the initial discovery of correlated phases in twisted bilayer graphene, a wide range of moiré materials have emerged with fascinating electronic properties. While the field of twistronics has rapidly evolved and now includes a range of multi-layered systems, moiré systems comprised of double trilayer graphene remain elusive. Here, we report electrical transport measurements combined with tight-binding calculations in twisted double trilayer graphene (TDTLG). We demonstrate that small-angle TDTLG (~1.7−2.0∘) exhibits an intrinsic bandgap at the charge neutrality point. Moreover, by tuning the displacement field, we observe a continuous insulator-semimetal-insulator transition at the CNP, which is also captured by tight-binding calculations. These results establish TDTLG systems as a highly tunable platform for further exploration of magneto-transport and optoelectronic properties.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-8"},"PeriodicalIF":9.7,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00449-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139987485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-26DOI: 10.1038/s41699-024-00451-2
Kazue Orikasa, Cheol Park, Sang-Hyon Chu, Calista Lum, Tony Thomas, Tyler Dolmetsch, Luiza Benedetti, Arvind Agarwal
Neutron radiation exposure is one of the main challenges faced during space missions. There is a critical need for advanced lightweight radiation shielding materials. Two-dimensional (2D) boron nitride nanoplatelets (BNNP) are excellent candidates for polymer matrix nanofillers due to their superior neutron shielding and thermal and mechanical properties. Furthermore, the 2D material anisotropic behavior unlocks the potential for composite property tailoring. This study fabricated ultra-lightweight lamellar BNNP foams (density 0.05 g cm–3 and 97.5% porous) via freeze-drying processing. The neutron shielding effectiveness or mass absorption coefficient of the BNNP foams with walls perpendicular to the direction of the radiation source was 14.47 cm2 g–1, while that of the foam with parallel configuration was only 8.51 cm2 g–1. The orientation-dependent neutron radiation shielding properties were modeled using the Beer-Lambert law for porous composite materials. The BNNP foam in this study has the potential to benefit advanced tailorable radiation shielding technologies for future aerospace missions.
{"title":"Foam with direction: unraveling the anisotropic radiation shielding properties of 2D boron nitride nanoplatelet foams","authors":"Kazue Orikasa, Cheol Park, Sang-Hyon Chu, Calista Lum, Tony Thomas, Tyler Dolmetsch, Luiza Benedetti, Arvind Agarwal","doi":"10.1038/s41699-024-00451-2","DOIUrl":"10.1038/s41699-024-00451-2","url":null,"abstract":"Neutron radiation exposure is one of the main challenges faced during space missions. There is a critical need for advanced lightweight radiation shielding materials. Two-dimensional (2D) boron nitride nanoplatelets (BNNP) are excellent candidates for polymer matrix nanofillers due to their superior neutron shielding and thermal and mechanical properties. Furthermore, the 2D material anisotropic behavior unlocks the potential for composite property tailoring. This study fabricated ultra-lightweight lamellar BNNP foams (density 0.05 g cm–3 and 97.5% porous) via freeze-drying processing. The neutron shielding effectiveness or mass absorption coefficient of the BNNP foams with walls perpendicular to the direction of the radiation source was 14.47 cm2 g–1, while that of the foam with parallel configuration was only 8.51 cm2 g–1. The orientation-dependent neutron radiation shielding properties were modeled using the Beer-Lambert law for porous composite materials. The BNNP foam in this study has the potential to benefit advanced tailorable radiation shielding technologies for future aerospace missions.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-9"},"PeriodicalIF":9.7,"publicationDate":"2024-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00451-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139976627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Atomically thin indium selenide (InSe) exhibits a sombrero-like valence band, leading to distinctive excitonic behaviors. It is known that the indirect band gap of atomically thin InSe leads to a weak emission from the lowest-energy excitonic state (A peak). However, the A peak emission of monolayer (ML) InSe was observed to be either absent or very weak, rendering the nature of its excitonic states largely unknown. Intriguingly, we demonstrate that ML InSe exhibits pronounced PL emission because of the efficient brightening of the momentum-indirect dark excitons. The mechanism is attributed to acoustic phonon-assisted radiative recombination facilitated by strong exciton-acoustic phonon coupling and extended wavefunction in momentum space. Systematic analysis of layer-, power-, and temperature-dependent PL demonstrates that a carrier localization model can account for the asymmetric line shape of the lowest-energy excitonic emission for atomically thin InSe. Our work reveals that atomically thin InSe is a promising platform for manipulating the tightly bound dark excitons in two-dimensional semiconductor-based optoelectronic devices.
原子级薄硒化铟（InSe）具有类似于 "羊角辫 "的价带，因而具有独特的激子行为。众所周知，原子级薄硒化铟的间接带隙会导致最低能量激发态（A 峰）的微弱发射。然而，观察发现单层（ML）硒铟的 A 峰发射要么不存在，要么非常微弱，因此其激子态的性质在很大程度上是未知的。有趣的是，我们证明了 ML InSe 由于动量直接暗激子的高效增亮而表现出明显的 PL 发射。这种机制可归因于激子-声子强耦合和动量空间扩展波函数促进的声子辅助辐射重组。对随层、随功率和随温度变化的 PL 的系统分析表明，载流子局域化模型可以解释原子薄硒铟的最低能量激子发射的非对称线形。我们的研究揭示了原子级薄铟硒是在基于二维半导体的光电器件中操纵紧密结合的暗激子的一个前景广阔的平台。
{"title":"Monolayer indium selenide: an indirect bandgap material exhibits efficient brightening of dark excitons","authors":"Naomi Tabudlong Paylaga, Chang-Ti Chou, Chia-Chun Lin, Takashi Taniguchi, Kenji Watanabe, Raman Sankar, Yang-hao Chan, Shao-Yu Chen, Wei-Hua Wang","doi":"10.1038/s41699-024-00450-3","DOIUrl":"10.1038/s41699-024-00450-3","url":null,"abstract":"Atomically thin indium selenide (InSe) exhibits a sombrero-like valence band, leading to distinctive excitonic behaviors. It is known that the indirect band gap of atomically thin InSe leads to a weak emission from the lowest-energy excitonic state (A peak). However, the A peak emission of monolayer (ML) InSe was observed to be either absent or very weak, rendering the nature of its excitonic states largely unknown. Intriguingly, we demonstrate that ML InSe exhibits pronounced PL emission because of the efficient brightening of the momentum-indirect dark excitons. The mechanism is attributed to acoustic phonon-assisted radiative recombination facilitated by strong exciton-acoustic phonon coupling and extended wavefunction in momentum space. Systematic analysis of layer-, power-, and temperature-dependent PL demonstrates that a carrier localization model can account for the asymmetric line shape of the lowest-energy excitonic emission for atomically thin InSe. Our work reveals that atomically thin InSe is a promising platform for manipulating the tightly bound dark excitons in two-dimensional semiconductor-based optoelectronic devices.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-9"},"PeriodicalIF":9.7,"publicationDate":"2024-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00450-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139915801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-14DOI: 10.1038/s41699-024-00446-z
Hikari Kitadai, Qishuo Tan, Lu Ping, Xi Ling
Surface-enhanced Raman spectroscopy (SERS) is a powerful technique for trace-level fingerprinting. Recently, layered two-dimensional (2D) materials have gained significant interest as SERS substrates for providing stable, uniform, and reproducible Raman enhancement with the potential for trace-level detection. Yet, the development of effective 2D SERS substrates is still hindered by the lack of fundamental understanding of the coupling mechanism between target molecules and substrates. Here, we report a systematic excitation-dependent Raman spectroscopy investigation on the coupling between 2D materials such as SnS2, MoS2, WSe2, and graphene and small organic molecules like rhodamine 6G (Rh 6G). Strong coupling between SnS2 and Rh 6G is found due to their degenerate excitons through Raman excitation profiles (REP), leading to the enhancement of Rh 6G vibrational modes that are observable down to 10−13 M. Our study shows that exciton coupling in the substrate-adsorbate complex plays a vital role in the Raman enhancement effect, opening a new route for designing SERS substrates for high sensitivity.
{"title":"Raman enhancement induced by exciton hybridization in molecules and 2D materials","authors":"Hikari Kitadai, Qishuo Tan, Lu Ping, Xi Ling","doi":"10.1038/s41699-024-00446-z","DOIUrl":"10.1038/s41699-024-00446-z","url":null,"abstract":"Surface-enhanced Raman spectroscopy (SERS) is a powerful technique for trace-level fingerprinting. Recently, layered two-dimensional (2D) materials have gained significant interest as SERS substrates for providing stable, uniform, and reproducible Raman enhancement with the potential for trace-level detection. Yet, the development of effective 2D SERS substrates is still hindered by the lack of fundamental understanding of the coupling mechanism between target molecules and substrates. Here, we report a systematic excitation-dependent Raman spectroscopy investigation on the coupling between 2D materials such as SnS2, MoS2, WSe2, and graphene and small organic molecules like rhodamine 6G (Rh 6G). Strong coupling between SnS2 and Rh 6G is found due to their degenerate excitons through Raman excitation profiles (REP), leading to the enhancement of Rh 6G vibrational modes that are observable down to 10−13 M. Our study shows that exciton coupling in the substrate-adsorbate complex plays a vital role in the Raman enhancement effect, opening a new route for designing SERS substrates for high sensitivity.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-8"},"PeriodicalIF":9.7,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00446-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139732419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Topological insulators (TIs) are emerging materials for next-generation low-power nanoelectronic and spintronic device applications. TIs possess non-trivial spin-momentum locking features in the topological surface states in addition to the spin-Hall effect (SHE), and Rashba states due to high spin-orbit coupling (SOC) properties. These phenomena are vital for observing the charge-spin conversion (CSC) processes for spin-based memory, logic and quantum technologies. Although CSC has been observed in TIs by potentiometric measurements, reliable nonlocal detection has so far been limited to cryogenic temperatures up to T = 15 K. Here, we report nonlocal detection of CSC and its inverse effect in the TI compound Bi1.5Sb0.5Te1.7Se1.3 at room temperature using a van der Waals heterostructure with a graphene spin-valve device. The lateral nonlocal device design with graphene allows observation of both spin-switch and Hanle spin precession signals for generation, injection and detection of spin currents by the TI. Detailed bias- and gate-dependent measurements in different geometries prove the robustness of the CSC effects in the TI. These findings demonstrate the possibility of using topological materials to make all-electrical room-temperature spintronic devices.
拓扑绝缘体（TIs）是下一代低功耗纳米电子和自旋电子器件应用的新兴材料。除了自旋霍尔效应（SHE）和高自旋轨道耦合（SOC）特性导致的拉什巴状态外，拓扑绝缘体的表面态还具有非三重自旋动量锁定特性。这些现象对于观察基于自旋的存储器、逻辑和量子技术的电荷-自旋转换（CSC）过程至关重要。这里，我们报告了在室温条件下，利用带有石墨烯自旋阀器件的范德华异质结构，在 TI 化合物 Bi1.5Sb0.5Te1.7Se1.3 中对 CSC 及其反向效应的非局部探测。利用石墨烯的横向非局部器件设计，可以观察到自旋开关和汉乐自旋前驱信号，从而通过 TI 产生、注入和检测自旋电流。在不同几何结构中进行的偏置和栅极依赖性详细测量证明了 TI 中 CSC 效应的稳健性。这些发现证明了使用拓扑材料制造全电室温自旋电子器件的可能性。
{"title":"Room temperature nonlocal detection of charge-spin interconversion in a topological insulator","authors":"Md. Anamul Hoque, Lars Sjöström, Dmitrii Khokhriakov, Bing Zhao, Saroj Prasad Dash","doi":"10.1038/s41699-024-00447-y","DOIUrl":"10.1038/s41699-024-00447-y","url":null,"abstract":"Topological insulators (TIs) are emerging materials for next-generation low-power nanoelectronic and spintronic device applications. TIs possess non-trivial spin-momentum locking features in the topological surface states in addition to the spin-Hall effect (SHE), and Rashba states due to high spin-orbit coupling (SOC) properties. These phenomena are vital for observing the charge-spin conversion (CSC) processes for spin-based memory, logic and quantum technologies. Although CSC has been observed in TIs by potentiometric measurements, reliable nonlocal detection has so far been limited to cryogenic temperatures up to T = 15 K. Here, we report nonlocal detection of CSC and its inverse effect in the TI compound Bi1.5Sb0.5Te1.7Se1.3 at room temperature using a van der Waals heterostructure with a graphene spin-valve device. The lateral nonlocal device design with graphene allows observation of both spin-switch and Hanle spin precession signals for generation, injection and detection of spin currents by the TI. Detailed bias- and gate-dependent measurements in different geometries prove the robustness of the CSC effects in the TI. These findings demonstrate the possibility of using topological materials to make all-electrical room-temperature spintronic devices.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-8"},"PeriodicalIF":9.7,"publicationDate":"2024-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00447-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139715268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-08DOI: 10.1038/s41699-024-00443-2
Matej Sebek, Zeng Wang, Norton Glen West, Ming Yang, Darren Chi Jin Neo, Xiaodi Su, Shijie Wang, Jisheng Pan, Nguyen Thi Kim Thanh, Jinghua Teng
A thin dielectric layer is an important constituent element in 2D materials-based electronics and photonics. Current methods of using hexagonal boron nitride (hBN) and direct deposition of dielectric layer induce either high leakage current or unintentional doping and defect. Here we report a technique for damaging free integration of dielectric layer to form high-quality van der Waals (vdW) heterostructure. The dielectric layer is grown by atomic layer deposition (ALD) on 2D materials and then deterministically transferred on the target 2D material. The much weaker binding energy between the ALD dielectric and the 2D materials enables the growth and exfoliation of the atomically thin dielectrics, which is confirmed by the X-ray photoelectron spectroscopy analyses and the density function theory calculations. The effectiveness of the technology is proven by the Raman and photoluminescence measurement on WS2 monolayer protected by the dielectric film through harsh plasma treatment. Furthermore, a 2D materials-based MOSFET is constructed as a demonstration of the viability of the technology for electronic device applications. The method produces flat surfaces and clean interfaces and would greatly benefit electronic and photonic applications as encapsulation or high-κ gate dielectric.
{"title":"Van der Waals enabled formation and integration of ultrathin high-κ dielectrics on 2D semiconductors","authors":"Matej Sebek, Zeng Wang, Norton Glen West, Ming Yang, Darren Chi Jin Neo, Xiaodi Su, Shijie Wang, Jisheng Pan, Nguyen Thi Kim Thanh, Jinghua Teng","doi":"10.1038/s41699-024-00443-2","DOIUrl":"10.1038/s41699-024-00443-2","url":null,"abstract":"A thin dielectric layer is an important constituent element in 2D materials-based electronics and photonics. Current methods of using hexagonal boron nitride (hBN) and direct deposition of dielectric layer induce either high leakage current or unintentional doping and defect. Here we report a technique for damaging free integration of dielectric layer to form high-quality van der Waals (vdW) heterostructure. The dielectric layer is grown by atomic layer deposition (ALD) on 2D materials and then deterministically transferred on the target 2D material. The much weaker binding energy between the ALD dielectric and the 2D materials enables the growth and exfoliation of the atomically thin dielectrics, which is confirmed by the X-ray photoelectron spectroscopy analyses and the density function theory calculations. The effectiveness of the technology is proven by the Raman and photoluminescence measurement on WS2 monolayer protected by the dielectric film through harsh plasma treatment. Furthermore, a 2D materials-based MOSFET is constructed as a demonstration of the viability of the technology for electronic device applications. The method produces flat surfaces and clean interfaces and would greatly benefit electronic and photonic applications as encapsulation or high-κ gate dielectric.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-9"},"PeriodicalIF":9.7,"publicationDate":"2024-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00443-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139710642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-02DOI: 10.1038/s41699-024-00445-0
Yu. Yu. Illarionov, A. Karl, Q. Smets, B. Kaczer, T. Knobloch, L. Panarella, T. Schram, S. Brems, D. Cott, I. Asselberghs, T. Grasser
Recent advances in fabricating field-effect transistors with MoS2 and other related two-dimensional (2D) semiconductors have inspired the industry to begin with the integration of these emerging technologies into FAB-compatible process flows. Just like in the lab research on 2D devices performed in the last decade, focus during development is typically put on pure technology-related issues, such as low-temperature growth methods of large-area 2D films on target substrates, damage-free transfer from sacrificial substrates and growth of top-gate oxides. With maturing technology, the problem of stability limitations caused by oxide traps is gradually coming into focus now. Thus, here we report an in-depth analysis of hysteresis and bias-temperature instabilities for MoS2 FETs fabricated using a 300 mm FAB-compatible process. By performing a comprehensive statistical analysis on devices with top gate lengths ranging between 18 nm and 10 μm, we demonstrate that aggressive scaling results in additional stability problems, likely caused by defective edges of the scaled top gates, in particular at higher operation temperatures. These are important insights for understanding and addressing the stability limitations in future nanoscale 2D FETs produced using FAB process lines.
利用 MoS2 和其他相关二维（2D）半导体制造场效应晶体管方面的最新进展，促使业界开始将这些新兴技术集成到 FAB 兼容工艺流程中。与过去十年间进行的二维器件实验室研究一样，开发过程中的重点通常放在纯技术相关的问题上，如目标基底上大面积二维薄膜的低温生长方法、牺牲基底的无损转移以及顶栅氧化物的生长。随着技术的不断成熟，氧化物陷阱导致的稳定性限制问题也逐渐成为焦点。因此，我们在此报告了对使用 300 毫米 FAB 兼容工艺制造的 MoS2 FET 的磁滞和偏置-温度不稳定性的深入分析。通过对顶栅长度介于 18 nm 和 10 μm 之间的器件进行全面的统计分析，我们证明了激进的缩放会导致额外的稳定性问题，这可能是由缩放顶栅的缺陷边缘引起的，尤其是在较高的工作温度下。这些见解对于理解和解决未来使用 FAB 工艺线生产的纳米级二维场效应晶体管的稳定性限制问题非常重要。
{"title":"Process implications on the stability and reliability of 300 mm FAB MoS2 field-effect transistors","authors":"Yu. Yu. Illarionov, A. Karl, Q. Smets, B. Kaczer, T. Knobloch, L. Panarella, T. Schram, S. Brems, D. Cott, I. Asselberghs, T. Grasser","doi":"10.1038/s41699-024-00445-0","DOIUrl":"10.1038/s41699-024-00445-0","url":null,"abstract":"Recent advances in fabricating field-effect transistors with MoS2 and other related two-dimensional (2D) semiconductors have inspired the industry to begin with the integration of these emerging technologies into FAB-compatible process flows. Just like in the lab research on 2D devices performed in the last decade, focus during development is typically put on pure technology-related issues, such as low-temperature growth methods of large-area 2D films on target substrates, damage-free transfer from sacrificial substrates and growth of top-gate oxides. With maturing technology, the problem of stability limitations caused by oxide traps is gradually coming into focus now. Thus, here we report an in-depth analysis of hysteresis and bias-temperature instabilities for MoS2 FETs fabricated using a 300 mm FAB-compatible process. By performing a comprehensive statistical analysis on devices with top gate lengths ranging between 18 nm and 10 μm, we demonstrate that aggressive scaling results in additional stability problems, likely caused by defective edges of the scaled top gates, in particular at higher operation temperatures. These are important insights for understanding and addressing the stability limitations in future nanoscale 2D FETs produced using FAB process lines.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-7"},"PeriodicalIF":9.7,"publicationDate":"2024-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00445-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139676865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-30DOI: 10.1038/s41699-024-00444-1
J. B. Roldán, A. Cantudo, J. J. Torres, D. Maldonado, Yaqing Shen, Wenwen Zheng, Yue Yuan, M. Lanza
Stochastic resonance is an essential phenomenon in neurobiology, it is connected to the constructive role of noise in the signals that take place in neuronal tissues, facilitating information communication, memory, etc. Memristive devices are known to be the cornerstone of hardware neuromorphic applications since they correctly mimic biological synapses in many different facets, such as short/long-term plasticity, spike-timing-dependent plasticity, pair-pulse facilitation, etc. Different types of neural networks can be built with circuit architectures based on memristive devices (mostly spiking neural networks and artificial neural networks). In this context, stochastic resonance is a critical issue to analyze in the memristive devices that will allow the fabrication of neuromorphic circuits. We do so here with h-BN based memristive devices from different perspectives. It is found that the devices we have fabricated and measured clearly show stochastic resonance behaviour. Consequently, neuromorphic applications can be developed to account for this effect, that describes a key issue in neurobiology with strong computational implications.
{"title":"Stochastic resonance in 2D materials based memristors","authors":"J. B. Roldán, A. Cantudo, J. J. Torres, D. Maldonado, Yaqing Shen, Wenwen Zheng, Yue Yuan, M. Lanza","doi":"10.1038/s41699-024-00444-1","DOIUrl":"10.1038/s41699-024-00444-1","url":null,"abstract":"Stochastic resonance is an essential phenomenon in neurobiology, it is connected to the constructive role of noise in the signals that take place in neuronal tissues, facilitating information communication, memory, etc. Memristive devices are known to be the cornerstone of hardware neuromorphic applications since they correctly mimic biological synapses in many different facets, such as short/long-term plasticity, spike-timing-dependent plasticity, pair-pulse facilitation, etc. Different types of neural networks can be built with circuit architectures based on memristive devices (mostly spiking neural networks and artificial neural networks). In this context, stochastic resonance is a critical issue to analyze in the memristive devices that will allow the fabrication of neuromorphic circuits. We do so here with h-BN based memristive devices from different perspectives. It is found that the devices we have fabricated and measured clearly show stochastic resonance behaviour. Consequently, neuromorphic applications can be developed to account for this effect, that describes a key issue in neurobiology with strong computational implications.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-6"},"PeriodicalIF":9.7,"publicationDate":"2024-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00444-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139643963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-27DOI: 10.1038/s41699-024-00441-4
Daniel J. Gillard, Daniel Wolverson, Oscar M. Hutchings, Alexander I. Tartakovskii
Layered antiferromagnetic materials have recently emerged as an intriguing subset of the two-dimensional family providing a highly accessible regime with prospects for layer-number-dependent magnetism. Furthermore, transition metal phosphorus trichalcogenides, MPX3 (M = transition metal; X = chalcogen) provide a platform on which to investigate fundamental interactions between magnetic and lattice degrees of freedom and further explore the developing fields of spintronics and magnonics. Here, we use a combination of temperature dependent Raman spectroscopy and density functional theory to explore magnetic-ordering-dependent interactions between the manganese spin degree of freedom and lattice vibrations of the non-magnetic sub-lattice via a Kramers-Anderson super-exchange pathway in both bulk, and few-layer, manganese phosphorus triselenide (MnPSe3). We observe a nonlinear temperature-dependent shift of phonon modes predominantly associated with the non-magnetic sub-lattice, revealing their non-trivial spin-phonon coupling below the Néel temperature at 74 K, allowing us to extract mode-specific spin-phonon coupling constants.
{"title":"Spin-order-dependent magneto-elastic coupling in two dimensional antiferromagnetic MnPSe3 observed through Raman spectroscopy","authors":"Daniel J. Gillard, Daniel Wolverson, Oscar M. Hutchings, Alexander I. Tartakovskii","doi":"10.1038/s41699-024-00441-4","DOIUrl":"10.1038/s41699-024-00441-4","url":null,"abstract":"Layered antiferromagnetic materials have recently emerged as an intriguing subset of the two-dimensional family providing a highly accessible regime with prospects for layer-number-dependent magnetism. Furthermore, transition metal phosphorus trichalcogenides, MPX3 (M = transition metal; X = chalcogen) provide a platform on which to investigate fundamental interactions between magnetic and lattice degrees of freedom and further explore the developing fields of spintronics and magnonics. Here, we use a combination of temperature dependent Raman spectroscopy and density functional theory to explore magnetic-ordering-dependent interactions between the manganese spin degree of freedom and lattice vibrations of the non-magnetic sub-lattice via a Kramers-Anderson super-exchange pathway in both bulk, and few-layer, manganese phosphorus triselenide (MnPSe3). We observe a nonlinear temperature-dependent shift of phonon modes predominantly associated with the non-magnetic sub-lattice, revealing their non-trivial spin-phonon coupling below the Néel temperature at 74 K, allowing us to extract mode-specific spin-phonon coupling constants.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-8"},"PeriodicalIF":9.7,"publicationDate":"2024-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00441-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139590546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-24DOI: 10.1038/s41699-024-00442-3
Sergio Puebla, Hao Li, Onur Çakıroğlu, Estrella Sánchez-Viso, C. Munuera, Roberto D’Agosta, Andres Castellanos-Gomez
This work investigates the vibrational and electrical properties of molybdenum trioxide (α-MoO3) upon tensile strain applied along different crystal directions. Using a three-point bending setup in combination with Raman spectroscopy, we report measurements of a blueshift of the Raman modes when uniaxial tensile strain is applied along the a- and c-axis to this material. Furthermore, the electrical measurements reveal an increase in resistance with strain applied along both in-plane directions. The findings from the uniaxial strain and Raman spectroscopy measurements are further confirmed by ab-initio calculations. This study provides valuable insights into the mechanical and vibrational properties of α-MoO3 and its potential use in several applications. This study contributes to the growing body of knowledge on the properties of α-MoO3 and lays the foundation for further exploration of its potential applications. Given MoO3 holding the natural hyperbolic phonon polaritons, attracting significant research interest, this study has the potential to arouse the curiosity of the scientific community.
这项研究探讨了三氧化钼（α-MoO3）在沿不同晶体方向施加拉伸应变时的振动和电学特性。利用三点弯曲装置和拉曼光谱，我们报告了沿 a 轴和 c 轴施加单轴拉伸应变时拉曼模式蓝移的测量结果。此外，电学测量结果表明，沿两个面内方向施加应变时，电阻会增加。非线性计算进一步证实了单轴应变和拉曼光谱测量的结果。这项研究为了解 α-MoO3 的机械和振动特性及其在多种应用中的潜在用途提供了宝贵的见解。这项研究有助于丰富有关 α-MoO3 性质的知识，并为进一步探索其潜在应用奠定了基础。鉴于 MoO3 拥有天然的双曲声子极化子，吸引了大量的研究兴趣，这项研究有可能引起科学界的好奇心。
{"title":"Strain tuning MoO3 vibrational and electronic properties","authors":"Sergio Puebla, Hao Li, Onur Çakıroğlu, Estrella Sánchez-Viso, C. Munuera, Roberto D’Agosta, Andres Castellanos-Gomez","doi":"10.1038/s41699-024-00442-3","DOIUrl":"10.1038/s41699-024-00442-3","url":null,"abstract":"This work investigates the vibrational and electrical properties of molybdenum trioxide (α-MoO3) upon tensile strain applied along different crystal directions. Using a three-point bending setup in combination with Raman spectroscopy, we report measurements of a blueshift of the Raman modes when uniaxial tensile strain is applied along the a- and c-axis to this material. Furthermore, the electrical measurements reveal an increase in resistance with strain applied along both in-plane directions. The findings from the uniaxial strain and Raman spectroscopy measurements are further confirmed by ab-initio calculations. This study provides valuable insights into the mechanical and vibrational properties of α-MoO3 and its potential use in several applications. This study contributes to the growing body of knowledge on the properties of α-MoO3 and lays the foundation for further exploration of its potential applications. Given MoO3 holding the natural hyperbolic phonon polaritons, attracting significant research interest, this study has the potential to arouse the curiosity of the scientific community.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-9"},"PeriodicalIF":9.7,"publicationDate":"2024-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00442-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139556768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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