Pub Date : 2024-03-20DOI: 10.1038/s41699-024-00459-8
Sergii Morozov, Torgom Yezekyan, Christian Wolff, Sergey I. Bozhevolnyi, N. Asger Mortensen
The lowest energy states in transition metal dichalcogenide (TMD) monolayers follow valley selection rules, which have attracted vast interest due to the possibility of encoding and processing of quantum information. However, these quantum states are strongly affected by temperature-dependent intervalley scattering leading to complete valley depolarization, which hampers practical applications at room temperature. Therefore, for achieving clear and robust valley polarization in TMD monolayers one needs to suppress parasitic depolarization processes, which is the central challenge in the growing field of valleytronics. Here, in electron-doping experiments on TMD monolayers, we show that strong doping levels beyond 1013 cm−2 can induce 61% and 37% valley contrast at room temperature in tungsten diselenide and molybdenum diselenide monolayers, respectively. Our findings demonstrate that charged excitons in TMD monolayers hold the potential for the development of efficient valleytronic devices functional at 300 K.
{"title":"Inducing room-temperature valley polarization of excitonic emission in transition metal dichalcogenide monolayers","authors":"Sergii Morozov, Torgom Yezekyan, Christian Wolff, Sergey I. Bozhevolnyi, N. Asger Mortensen","doi":"10.1038/s41699-024-00459-8","DOIUrl":"10.1038/s41699-024-00459-8","url":null,"abstract":"The lowest energy states in transition metal dichalcogenide (TMD) monolayers follow valley selection rules, which have attracted vast interest due to the possibility of encoding and processing of quantum information. However, these quantum states are strongly affected by temperature-dependent intervalley scattering leading to complete valley depolarization, which hampers practical applications at room temperature. Therefore, for achieving clear and robust valley polarization in TMD monolayers one needs to suppress parasitic depolarization processes, which is the central challenge in the growing field of valleytronics. Here, in electron-doping experiments on TMD monolayers, we show that strong doping levels beyond 1013 cm−2 can induce 61% and 37% valley contrast at room temperature in tungsten diselenide and molybdenum diselenide monolayers, respectively. Our findings demonstrate that charged excitons in TMD monolayers hold the potential for the development of efficient valleytronic devices functional at 300 K.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-6"},"PeriodicalIF":9.7,"publicationDate":"2024-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00459-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140181739","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 : 2024-03-19DOI: 10.1038/s41699-024-00461-0
Yu. Yu. Illarionov, T. Knobloch, B. Uzlu, A. G. Banshchikov, I. A. Ivanov, V. Sverdlov, M. Otto, S. L. Stoll, M. I. Vexler, M. Waltl, Z. Wang, B. Manna, D. Neumaier, M. C. Lemme, N. S. Sokolov, T. Grasser
Graphene is a promising material for applications as a channel in graphene field-effect transistors (GFETs) which may be used as a building block for optoelectronics, high-frequency devices and sensors. However, these devices require gate insulators which ideally should form atomically flat interfaces with graphene and at the same time contain small densities of traps to maintain high device stability. Previously used amorphous oxides, such as SiO2 and Al2O3, however, typically suffer from oxide dangling bonds at the interface, high surface roughness and numerous border oxide traps. In order to address these challenges, here we use 2 nm thick epitaxial CaF2 as a gate insulator in GFETs. By analyzing device-to-device variability for about 200 devices fabricated in two batches, we find that tens of them show similar gate transfer characteristics. Our statistical analysis of the hysteresis up to 175oC has revealed that while an ambient-sensitive counterclockwise hysteresis can be present in some devices, the dominant mechanism is thermally activated charge trapping by border defects in CaF2 which results in the conventional clockwise hysteresis. We demonstrate that both the hysteresis and bias-temperature instabilities in our GFETs with CaF2 are comparable to similar devices with SiO2 and Al2O3. In particular, we achieve a small hysteresis below 0.01 V for equivalent oxide thickness (EOT) of about 1 nm at the electric fields up to 15 MV cm−1 and sweep times in the kilosecond range. Thus, our results demonstrate that crystalline CaF2 is a promising insulator for highly-stable GFETs.
{"title":"Variability and high temperature reliability of graphene field-effect transistors with thin epitaxial CaF2 insulators","authors":"Yu. Yu. Illarionov, T. Knobloch, B. Uzlu, A. G. Banshchikov, I. A. Ivanov, V. Sverdlov, M. Otto, S. L. Stoll, M. I. Vexler, M. Waltl, Z. Wang, B. Manna, D. Neumaier, M. C. Lemme, N. S. Sokolov, T. Grasser","doi":"10.1038/s41699-024-00461-0","DOIUrl":"10.1038/s41699-024-00461-0","url":null,"abstract":"Graphene is a promising material for applications as a channel in graphene field-effect transistors (GFETs) which may be used as a building block for optoelectronics, high-frequency devices and sensors. However, these devices require gate insulators which ideally should form atomically flat interfaces with graphene and at the same time contain small densities of traps to maintain high device stability. Previously used amorphous oxides, such as SiO2 and Al2O3, however, typically suffer from oxide dangling bonds at the interface, high surface roughness and numerous border oxide traps. In order to address these challenges, here we use 2 nm thick epitaxial CaF2 as a gate insulator in GFETs. By analyzing device-to-device variability for about 200 devices fabricated in two batches, we find that tens of them show similar gate transfer characteristics. Our statistical analysis of the hysteresis up to 175oC has revealed that while an ambient-sensitive counterclockwise hysteresis can be present in some devices, the dominant mechanism is thermally activated charge trapping by border defects in CaF2 which results in the conventional clockwise hysteresis. We demonstrate that both the hysteresis and bias-temperature instabilities in our GFETs with CaF2 are comparable to similar devices with SiO2 and Al2O3. In particular, we achieve a small hysteresis below 0.01 V for equivalent oxide thickness (EOT) of about 1 nm at the electric fields up to 15 MV cm−1 and sweep times in the kilosecond range. Thus, our results demonstrate that crystalline CaF2 is a promising insulator for highly-stable GFETs.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-10"},"PeriodicalIF":9.7,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00461-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140181737","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 : 2024-03-18DOI: 10.1038/s41699-024-00460-1
Mingjie Wang, Bin Lei, Kejia Zhu, Yazhou Deng, Mingliang Tian, Ziji Xiang, Tao Wu, Xianhui Chen
Two-dimensional (2D) magnetic materials are of not only fundamental scientific interest but also promising candidates for numerous applications. However, so far only a few intrinsic magnets with long-ranged order down to the 2D limit have been experimentally established. Here, we report that the intrinsic 2D ferromagnetism can be realized in van der Waals (vdW) Fe3GaTe2 nanoflake down to monolayer. By measuring the Hall resistance and magnetoresistance, we demonstrate that the Fe3GaTe2 monolayer exhibits 2D hard ferromagnetism with record-high Cure temperature (Tc) of 240 K for the monolayer of known intrinsic ferromagnets. Both of square-shaped hysteresis loops with near-vertical jump in anomalous Hall effect (AHE) and the negative magnetoresistance (NMR) behavior with an applied out-of-plane magnetic field reveal robust perpendicular magnetic anisotropy (PMA) in Fe3GaTe2 nanoflakes down to the monolayer limit. Furthermore, we find the intrinsic mechanism that stems from the Berry curvature of electronic bands dominates AHE of nanoflakes in the low temperature range. Our results not only provide an excellent candidate material for next-generation spintronic applications, but also open up a platform for exploring physical mechanisms in 2D ferromagnetism.
{"title":"Hard ferromagnetism in van der Waals Fe3GaTe2 nanoflake down to monolayer","authors":"Mingjie Wang, Bin Lei, Kejia Zhu, Yazhou Deng, Mingliang Tian, Ziji Xiang, Tao Wu, Xianhui Chen","doi":"10.1038/s41699-024-00460-1","DOIUrl":"10.1038/s41699-024-00460-1","url":null,"abstract":"Two-dimensional (2D) magnetic materials are of not only fundamental scientific interest but also promising candidates for numerous applications. However, so far only a few intrinsic magnets with long-ranged order down to the 2D limit have been experimentally established. Here, we report that the intrinsic 2D ferromagnetism can be realized in van der Waals (vdW) Fe3GaTe2 nanoflake down to monolayer. By measuring the Hall resistance and magnetoresistance, we demonstrate that the Fe3GaTe2 monolayer exhibits 2D hard ferromagnetism with record-high Cure temperature (Tc) of 240 K for the monolayer of known intrinsic ferromagnets. Both of square-shaped hysteresis loops with near-vertical jump in anomalous Hall effect (AHE) and the negative magnetoresistance (NMR) behavior with an applied out-of-plane magnetic field reveal robust perpendicular magnetic anisotropy (PMA) in Fe3GaTe2 nanoflakes down to the monolayer limit. Furthermore, we find the intrinsic mechanism that stems from the Berry curvature of electronic bands dominates AHE of nanoflakes in the low temperature range. Our results not only provide an excellent candidate material for next-generation spintronic applications, but also open up a platform for exploring physical mechanisms in 2D ferromagnetism.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-7"},"PeriodicalIF":9.7,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00460-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140167290","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 : 2024-03-14DOI: 10.1038/s41699-024-00458-9
Molla Manjurul Islam, Md Sazzadur Rahman, Haley Heldmyer, Sang Sub Han, Yeonwoong Jung, Tania Roy
In in-sensor image preprocessing, the sensed image undergoes low level processing like denoising at the sensor end, similar to the retina of human eye. Optoelectronic synapse devices are potential contenders for this purpose, and subsequent applications in artificial neural networks (ANNs). The optoelectronic synapses can offer image pre-processing functionalities at the pixel itself—termed as in-pixel computing. Denoising is an important problem in image preprocessing and several approaches have been used to denoise the input images. While most of those approaches require external circuitry, others are efficient only when the noisy pixels have significantly lower intensity compared to the actual pattern pixels. In this work, we present the innate ability of an optoelectronic synapse array to perform denoising at the pixel itself once it is trained to memorize an image. The synapses consist of phototransistors with bilayer MoS2 channel and p-Si/PtTe2 buried gate electrode. Our 7 × 7 array shows excellent robustness to noise due to the interplay between long-term potentiation and short-term potentiation. This bio-inspired strategy enables denoising of noise with higher intensity than the memorized pattern, without the use of any external circuitry. Specifically, due to the ability of these synapses to respond distinctively to wavelengths from 300 nm in ultraviolet to 2 µm in infrared, the pixel array also denoises mixed-color interferences. The “self-denoising” capability of such an artificial visual array has the capacity to eliminate the need for raw data transmission and thus, reduce subsequent image processing steps for supervised learning.
{"title":"Bio-inspired “Self-denoising” capability of 2D materials incorporated optoelectronic synaptic array","authors":"Molla Manjurul Islam, Md Sazzadur Rahman, Haley Heldmyer, Sang Sub Han, Yeonwoong Jung, Tania Roy","doi":"10.1038/s41699-024-00458-9","DOIUrl":"10.1038/s41699-024-00458-9","url":null,"abstract":"In in-sensor image preprocessing, the sensed image undergoes low level processing like denoising at the sensor end, similar to the retina of human eye. Optoelectronic synapse devices are potential contenders for this purpose, and subsequent applications in artificial neural networks (ANNs). The optoelectronic synapses can offer image pre-processing functionalities at the pixel itself—termed as in-pixel computing. Denoising is an important problem in image preprocessing and several approaches have been used to denoise the input images. While most of those approaches require external circuitry, others are efficient only when the noisy pixels have significantly lower intensity compared to the actual pattern pixels. In this work, we present the innate ability of an optoelectronic synapse array to perform denoising at the pixel itself once it is trained to memorize an image. The synapses consist of phototransistors with bilayer MoS2 channel and p-Si/PtTe2 buried gate electrode. Our 7 × 7 array shows excellent robustness to noise due to the interplay between long-term potentiation and short-term potentiation. This bio-inspired strategy enables denoising of noise with higher intensity than the memorized pattern, without the use of any external circuitry. Specifically, due to the ability of these synapses to respond distinctively to wavelengths from 300 nm in ultraviolet to 2 µm in infrared, the pixel array also denoises mixed-color interferences. The “self-denoising” capability of such an artificial visual array has the capacity to eliminate the need for raw data transmission and thus, reduce subsequent image processing steps for supervised learning.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-10"},"PeriodicalIF":9.7,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00458-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140123818","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 : 2024-03-12DOI: 10.1038/s41699-024-00448-x
José Tiago Carvalho, Afonso Correia, Neusmar J. A. Cordeiro, João Coelho, Sidney A. Lourenço, Elvira Fortunato, Rodrigo Martins, Luís Pereira
Academic and industrial efforts have focused on developing energy storage devices for wearable and portable electronics using low-cost, scalable, and sustainable materials and approaches. In this work, commercially available stretch-broken carbon fiber yarns (SBCFYs) were hybridized with mixed phases of 1 T and 2H MoS2 nanosheets via conventional and microwave-assisted heating (CAH, MAH) without the use of binders to fabricate symmetric freestanding 1D fiber-shaped supercapacitors (FSCs). Electrochemical characterization performed in a three-electrode configuration showed promising results with specific capacitance values of 184.41 and 180.02 F·g−1, at 1 mV·s−1 for CAH and MAH, respectively. Furthermore, after performing 3000 CV cycles at 100 mV·s−1, the capacitance retention was 79.5% and 95.7%, respectively. Using these results as a reference, symmetric 1D FSCs were fabricated by pairing hybridized SBCFYs with MoS2 by MAH. The devices exhibited specific capacitances of approximately 58.60 ± 3.06 F·g−1 at 1 mV·s−1 and 54.81 ± 7.34 F·g−1 at 0.2 A·g−1 with the highest power density achieved being 15.17 W·g−1 and energy density of 5.06×10–4 Wh·g−1. In addition, five 1D FSCs were hand-stitched and connected in series onto a cotton fabric. These supercapacitors could power a temperature and humidity sensor for up to six minutes, demonstrating the practicality and versatility of the prepared 1D FSCs for powering future electronic systems.
{"title":"MoS2 decorated carbon fiber yarn hybrids for the development of freestanding flexible supercapacitors","authors":"José Tiago Carvalho, Afonso Correia, Neusmar J. A. Cordeiro, João Coelho, Sidney A. Lourenço, Elvira Fortunato, Rodrigo Martins, Luís Pereira","doi":"10.1038/s41699-024-00448-x","DOIUrl":"10.1038/s41699-024-00448-x","url":null,"abstract":"Academic and industrial efforts have focused on developing energy storage devices for wearable and portable electronics using low-cost, scalable, and sustainable materials and approaches. In this work, commercially available stretch-broken carbon fiber yarns (SBCFYs) were hybridized with mixed phases of 1 T and 2H MoS2 nanosheets via conventional and microwave-assisted heating (CAH, MAH) without the use of binders to fabricate symmetric freestanding 1D fiber-shaped supercapacitors (FSCs). Electrochemical characterization performed in a three-electrode configuration showed promising results with specific capacitance values of 184.41 and 180.02 F·g−1, at 1 mV·s−1 for CAH and MAH, respectively. Furthermore, after performing 3000 CV cycles at 100 mV·s−1, the capacitance retention was 79.5% and 95.7%, respectively. Using these results as a reference, symmetric 1D FSCs were fabricated by pairing hybridized SBCFYs with MoS2 by MAH. The devices exhibited specific capacitances of approximately 58.60 ± 3.06 F·g−1 at 1 mV·s−1 and 54.81 ± 7.34 F·g−1 at 0.2 A·g−1 with the highest power density achieved being 15.17 W·g−1 and energy density of 5.06×10–4 Wh·g−1. In addition, five 1D FSCs were hand-stitched and connected in series onto a cotton fabric. These supercapacitors could power a temperature and humidity sensor for up to six minutes, demonstrating the practicality and versatility of the prepared 1D FSCs for powering future electronic systems.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-9"},"PeriodicalIF":9.7,"publicationDate":"2024-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00448-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140114367","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 : 2024-03-08DOI: 10.1038/s41699-024-00457-w
Rebti Bhushan, Arkamita Bandyopadhyay, Sangeeth Kallatt, Awalendra K. Thakur, Swapan K. Pati, Prashant Kumar
Insufficient carrier concentration and lack of room temperature ferromagnetism in pristine graphene limit its dream applications in electronic and spintronic chips. While theoretical calculations have revealed that graphitic ultradoping can turn graphene into semiconducting and room temperature ferromagnetic, the exotic set of thermodynamic conditions needed for doping result in defects and functionalities in graphene which end up giving significant electronic scattering. We report our discovery of microwave ultradoping of graphene with N > 30%, B ~ 19%, and co-doping to form BCN phases (B5C73N22, B8C76N16, and B10C77N13). An unprecedented level of graphitic doping ~95% enhances carrier concentration up to ~9.2 × 1012 cm−2, keeping high electronic mobility ~9688 cm2 V−1s−1 intact, demonstrated by field effect transistor measurements. Room temperature ferromagnetic character with magnetization ~4.18 emug−1 is reported and is consistent with our DFT band structure calculations. This breakthrough research on tunable graphitic ultradoping of 2D materials opens new avenues for emerging multi-functional technological applications.
{"title":"Microwave graphitic nitrogen/boron ultradoping of graphene","authors":"Rebti Bhushan, Arkamita Bandyopadhyay, Sangeeth Kallatt, Awalendra K. Thakur, Swapan K. Pati, Prashant Kumar","doi":"10.1038/s41699-024-00457-w","DOIUrl":"10.1038/s41699-024-00457-w","url":null,"abstract":"Insufficient carrier concentration and lack of room temperature ferromagnetism in pristine graphene limit its dream applications in electronic and spintronic chips. While theoretical calculations have revealed that graphitic ultradoping can turn graphene into semiconducting and room temperature ferromagnetic, the exotic set of thermodynamic conditions needed for doping result in defects and functionalities in graphene which end up giving significant electronic scattering. We report our discovery of microwave ultradoping of graphene with N > 30%, B ~ 19%, and co-doping to form BCN phases (B5C73N22, B8C76N16, and B10C77N13). An unprecedented level of graphitic doping ~95% enhances carrier concentration up to ~9.2 × 1012 cm−2, keeping high electronic mobility ~9688 cm2 V−1s−1 intact, demonstrated by field effect transistor measurements. Room temperature ferromagnetic character with magnetization ~4.18 emug−1 is reported and is consistent with our DFT band structure calculations. This breakthrough research on tunable graphitic ultradoping of 2D materials opens new avenues for emerging multi-functional technological applications.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-11"},"PeriodicalIF":9.7,"publicationDate":"2024-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00457-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140066618","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}
Due to their distinctive morphology, significant surface-to-volume ratio, and metal-like electrical conductivity, MXenes have emerged as highly promising gas-sensing materials. Traditional MXene-based gas sensors predominantly rely on the electrical conductivity of MXenes for signal transduction. However, it is crucial to explore alternative signal transduction mechanisms to fully unlock the potential of MXenes in gas sensing applications. In this study, we have successfully showcased the development of a mass-transduction-based MXene gas sensor, utilizing MXenes as the adaptable receptor and MQTF as the transducer. The interaction between the gas analyte and MXenes induces a change in mass, resulting in a resonant frequency shift of the MQTF. This signal transduction mechanism eliminates the dependency on the electrical conductivity of MXenes, offering a broader range of possibilities for chemical modification of MXenes without concerns about compromising their conductivity. By engineering Ti3C2Tx surfaces, we have demonstrated high sensitivity and selectivity tuning of MXene-MQTF gas sensors for detecting CO, SO2, and NH3. This antisymmetric mass-transduction-based (low-cost, stable, sensitive, and practical tuning fork-based) MXene gas sensor demonstrated exceptional sensing performance, customizable selectivity, and high cost-effectiveness. This study paves the way for designing high-performance MXene-based chemical sensors and expands the scope of potential applications in air quality monitoring, wearable devices, the Internet of Things (IoT), and robotics.
{"title":"Highly sensitive and reversible MXene-based micro quartz tuning fork gas sensors with tunable selectivity","authors":"Wei Ding, Jingjing Yu, Francis Tsow, Laxmi Raj Jaishi, Buddhi Sagar Lamsal, Rick Kittelson, Sarwar Ahmed, Parashu Kharel, Yue Zhou, Xiaojun Xian","doi":"10.1038/s41699-024-00452-1","DOIUrl":"10.1038/s41699-024-00452-1","url":null,"abstract":"Due to their distinctive morphology, significant surface-to-volume ratio, and metal-like electrical conductivity, MXenes have emerged as highly promising gas-sensing materials. Traditional MXene-based gas sensors predominantly rely on the electrical conductivity of MXenes for signal transduction. However, it is crucial to explore alternative signal transduction mechanisms to fully unlock the potential of MXenes in gas sensing applications. In this study, we have successfully showcased the development of a mass-transduction-based MXene gas sensor, utilizing MXenes as the adaptable receptor and MQTF as the transducer. The interaction between the gas analyte and MXenes induces a change in mass, resulting in a resonant frequency shift of the MQTF. This signal transduction mechanism eliminates the dependency on the electrical conductivity of MXenes, offering a broader range of possibilities for chemical modification of MXenes without concerns about compromising their conductivity. By engineering Ti3C2Tx surfaces, we have demonstrated high sensitivity and selectivity tuning of MXene-MQTF gas sensors for detecting CO, SO2, and NH3. This antisymmetric mass-transduction-based (low-cost, stable, sensitive, and practical tuning fork-based) MXene gas sensor demonstrated exceptional sensing performance, customizable selectivity, and high cost-effectiveness. This study paves the way for designing high-performance MXene-based chemical sensors and expands the scope of potential applications in air quality monitoring, wearable devices, the Internet of Things (IoT), and robotics.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-10"},"PeriodicalIF":9.7,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00452-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140045173","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 : 2024-03-06DOI: 10.1038/s41699-024-00456-x
Yixin Chen, Fengzhou Fang, Nan Zhang
Atomic and close-to-atomic scale manufacturing (ACSM) has emerged as promising technologies in the manufacturing paradigm. Among various materials, 2D materials have garnered significant attention for ACSM due to their atomic-scale characteristics and physical properties. While chemical vapor deposition (CVD) can be employed to produce high-quality 2D materials, achieving patterning often relies on photolithography techniques, which limit scalability and introduce impurities. To address these challenges, this article serves as a review by focusing on exploring atomic-scale additive manufacturing methods for 2D materials. Several potential techniques are reviewed, including site-selective CVD, area-selective atomic layer deposition, electrodeposition, laser-assisted synthesis, print methods, and atomic layer-aligned stacking. The applications of atomic-scale additive manufacturing in various fields, such as electronics, biosensing, and nanoelectromechanical systems, are discussed. Finally, the future prospects of atomic-scale additive manufacturing for 2D materials based on existing research are delved into.
{"title":"Advance in additive manufacturing of 2D materials at the atomic and close-to-atomic scale","authors":"Yixin Chen, Fengzhou Fang, Nan Zhang","doi":"10.1038/s41699-024-00456-x","DOIUrl":"10.1038/s41699-024-00456-x","url":null,"abstract":"Atomic and close-to-atomic scale manufacturing (ACSM) has emerged as promising technologies in the manufacturing paradigm. Among various materials, 2D materials have garnered significant attention for ACSM due to their atomic-scale characteristics and physical properties. While chemical vapor deposition (CVD) can be employed to produce high-quality 2D materials, achieving patterning often relies on photolithography techniques, which limit scalability and introduce impurities. To address these challenges, this article serves as a review by focusing on exploring atomic-scale additive manufacturing methods for 2D materials. Several potential techniques are reviewed, including site-selective CVD, area-selective atomic layer deposition, electrodeposition, laser-assisted synthesis, print methods, and atomic layer-aligned stacking. The applications of atomic-scale additive manufacturing in various fields, such as electronics, biosensing, and nanoelectromechanical systems, are discussed. Finally, the future prospects of atomic-scale additive manufacturing for 2D materials based on existing research are delved into.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-23"},"PeriodicalIF":9.7,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00456-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140044839","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 : 2024-03-02DOI: 10.1038/s41699-024-00455-y
Song Li, Anton Pershin, Pei Li, Adam Gali
Van der Waals structures present a unique opportunity for tailoring material interfaces and integrating photonic functionalities. By precisely manipulating the twist angle and stacking sequences, it is possible to elegantly tune and functionalize the electronic and optical properties of layered van der Waals structures. Among these materials, two-dimensional hexagonal boron nitride (hBN) stands out for its remarkable optical properties and wide band gap, making it a promising host for solid state single photon emitters at room temperature. Previous investigations have demonstrated the observation of bright single photon emission in hBN across a wide range of wavelengths. In this study, we unveil an application of van der Waals technology in modulating their spectral shapes and brightness by carefully controlling the stacking sequences and polytypes. Our theoretical analysis reveals remarkably large variations in the Huang-Rhys factors–an indicator of the interaction between a defect and its surrounding lattice–reaching up to a factor of 3.3 for the same defect in different stacking sequences. We provide insights into the underlying mechanism behind these variations, shedding light on the design principles necessary to achieve rational and precise control of defect emission. This work paves the way for enhancing defect identification and facilitating the engineering of highly efficient single photon sources and qubits using van der Waals materials.
{"title":"Exceptionally strong coupling of defect emission in hexagonal boron nitride to stacking sequences","authors":"Song Li, Anton Pershin, Pei Li, Adam Gali","doi":"10.1038/s41699-024-00455-y","DOIUrl":"10.1038/s41699-024-00455-y","url":null,"abstract":"Van der Waals structures present a unique opportunity for tailoring material interfaces and integrating photonic functionalities. By precisely manipulating the twist angle and stacking sequences, it is possible to elegantly tune and functionalize the electronic and optical properties of layered van der Waals structures. Among these materials, two-dimensional hexagonal boron nitride (hBN) stands out for its remarkable optical properties and wide band gap, making it a promising host for solid state single photon emitters at room temperature. Previous investigations have demonstrated the observation of bright single photon emission in hBN across a wide range of wavelengths. In this study, we unveil an application of van der Waals technology in modulating their spectral shapes and brightness by carefully controlling the stacking sequences and polytypes. Our theoretical analysis reveals remarkably large variations in the Huang-Rhys factors–an indicator of the interaction between a defect and its surrounding lattice–reaching up to a factor of 3.3 for the same defect in different stacking sequences. We provide insights into the underlying mechanism behind these variations, shedding light on the design principles necessary to achieve rational and precise control of defect emission. This work paves the way for enhancing defect identification and facilitating the engineering of highly efficient single photon sources and qubits using van der Waals materials.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-8"},"PeriodicalIF":9.7,"publicationDate":"2024-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00455-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140016465","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 : 2024-02-29DOI: 10.1038/s41699-024-00454-z
Kyu Hyun Han, Seung-Hwan Kim, Seung-Geun Kim, Jong-Hyun Kim, Sungjoo Song, Hyun-Yong Yu
With development of information age, multi-valued logic (MVL) technology utilizing negative differential transconductance (NDT) phenomenon has drawn attention as next-generation computing technology that can replace binary logic. However, because conventional NDT devices primarily use ternary logic, multiple-peak NDT device is required for higher-radix MVL that can process more datasets. Here, van der Waals double-peak anti-ambipolar transistor (AAT) as NDT device was developed by utilizing peak voltage (Vpeak) modulation of NDT peak. For realization of quaternary logic, Vpeak modulation technology was developed through charge transfer mechanism from channel, thereby shifting NDT peak and increasing peak-to-valley current ratio (PVCR). Furthermore, Double-peak AAT was implemented through parallel configuration of two AATs with different Vpeak values. Finally, quaternary inverter with four widely stable logic states was implemented by utilizing the developed double-peak AAT with two distinct NDT peaks and high PVCR. This double-peak AAT is expected to contribute to the development of next-generation MVL technology capable of processing datasets.
{"title":"Charge transfer mechanism for realization of double negative differential transconductance","authors":"Kyu Hyun Han, Seung-Hwan Kim, Seung-Geun Kim, Jong-Hyun Kim, Sungjoo Song, Hyun-Yong Yu","doi":"10.1038/s41699-024-00454-z","DOIUrl":"10.1038/s41699-024-00454-z","url":null,"abstract":"With development of information age, multi-valued logic (MVL) technology utilizing negative differential transconductance (NDT) phenomenon has drawn attention as next-generation computing technology that can replace binary logic. However, because conventional NDT devices primarily use ternary logic, multiple-peak NDT device is required for higher-radix MVL that can process more datasets. Here, van der Waals double-peak anti-ambipolar transistor (AAT) as NDT device was developed by utilizing peak voltage (Vpeak) modulation of NDT peak. For realization of quaternary logic, Vpeak modulation technology was developed through charge transfer mechanism from channel, thereby shifting NDT peak and increasing peak-to-valley current ratio (PVCR). Furthermore, Double-peak AAT was implemented through parallel configuration of two AATs with different Vpeak values. Finally, quaternary inverter with four widely stable logic states was implemented by utilizing the developed double-peak AAT with two distinct NDT peaks and high PVCR. This double-peak AAT is expected to contribute to the development of next-generation MVL technology capable of processing datasets.","PeriodicalId":19227,"journal":{"name":"npj 2D Materials and Applications","volume":" ","pages":"1-9"},"PeriodicalIF":9.7,"publicationDate":"2024-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41699-024-00454-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140000820","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}
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：