Pub Date : 2023-10-20DOI: 10.1088/1361-6463/acff02
Xiaobo Lin, Kangyu Su, Lanxin Yang, Chenyang Xing, Zhengchun Peng, Bo Meng
Abstract Power supply is playing an increasingly important role in the rapidly developing era of the Internet of Things. Achieving a sustainable and clean power supply for electronic devices is an urgent and challenging task. In this study, we present a heat-triggered triboelectric nanogenerator (TENG) and develop a self-powered fire alarm system to achieve an early warning without an external power supply. A TENG comprises a gear system that can utilize the elastic potential energy of a spring. A wax block was used as a heat trigger. When melted at high temperatures, the TENG will be triggered to work and generate considerable electric energy. Within a single operation cycle of approximately 6 s, a 22 μ F capacitor can be charged up to 3.7 V. Such electrical energy is sufficient to drive a wireless transmission module through an automatic switching circuit. Overall, this study provides a feasible approach for a self-powered wireless warning system in power-shortage areas.
{"title":"A heat-triggered triboelectric nanogenerator for self-powered wireless fire alarm","authors":"Xiaobo Lin, Kangyu Su, Lanxin Yang, Chenyang Xing, Zhengchun Peng, Bo Meng","doi":"10.1088/1361-6463/acff02","DOIUrl":"https://doi.org/10.1088/1361-6463/acff02","url":null,"abstract":"Abstract Power supply is playing an increasingly important role in the rapidly developing era of the Internet of Things. Achieving a sustainable and clean power supply for electronic devices is an urgent and challenging task. In this study, we present a heat-triggered triboelectric nanogenerator (TENG) and develop a self-powered fire alarm system to achieve an early warning without an external power supply. A TENG comprises a gear system that can utilize the elastic potential energy of a spring. A wax block was used as a heat trigger. When melted at high temperatures, the TENG will be triggered to work and generate considerable electric energy. Within a single operation cycle of approximately 6 s, a 22 μ F capacitor can be charged up to 3.7 V. Such electrical energy is sufficient to drive a wireless transmission module through an automatic switching circuit. Overall, this study provides a feasible approach for a self-powered wireless warning system in power-shortage areas.","PeriodicalId":16833,"journal":{"name":"Journal of Physics D","volume":"9 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135513408","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}
Pub Date : 2023-10-20DOI: 10.1088/1361-6463/ad0567
Shusheng Xie, Leilei Gu, Jianping Guo
Abstract Chiral plasmonic metamaterials can amplify chiral signals, resulting in circular dichroism (CD) responses that are several orders of magnitude far beyond those of nature. However, the design process of chiral plasmonic metamaterials based on conventional methods is time-consuming. In recent years, the combination of deep learning (DL) and nanophotonics have accelerated the design of nanophotonic devices. Here, we construct the fully connected neural network (FC-NN) model for the forward prediction and inverse design of chiral plasmonic metamaterials structures and introduce the permutation importance approach to optimize the model and increase its interpretability. Our experimental results show that using the peak magnitude of CD and the corresponding wavelength instead of the entire spectrum as the output in the forward prediction improves the accuracy of the peak magnitude of CD prediction, avoids the introduction of auxiliary networks, and simplifies the network structure; The permutation importance analysis shows that the gold length of the resonator is the most critical structural parameter affecting the CD response. In the inverse design, the permutation importance method helps us to make feature selections for the input of the network. By reducing 251 inputs (the whole CD spectrum) to 4 inputs (the peak magnitude of CD and the corresponding wavelength), the network can still maintain a good prediction performance and decrease the training time of the network. Our proposed method can be extended not only to other DL models to study the CD response of chiral metamaterials but also to other areas where DL is combined with metamaterials to accelerate the system optimization and design process of nanophotonic devices.
{"title":"Design of chiral plasmonic metamaterials based on interpretable deep learning","authors":"Shusheng Xie, Leilei Gu, Jianping Guo","doi":"10.1088/1361-6463/ad0567","DOIUrl":"https://doi.org/10.1088/1361-6463/ad0567","url":null,"abstract":"Abstract Chiral plasmonic metamaterials can amplify chiral signals, resulting in circular dichroism (CD) responses that are several orders of magnitude far beyond those of nature. However, the design process of chiral plasmonic metamaterials based on conventional methods is time-consuming. In recent years, the combination of deep learning (DL) and nanophotonics have accelerated the design of nanophotonic devices. Here, we construct the fully connected neural network (FC-NN) model for the forward prediction and inverse design of chiral plasmonic metamaterials structures and introduce the permutation importance approach to optimize the model and increase its interpretability. Our experimental results show that using the peak magnitude of CD and the corresponding wavelength instead of the entire spectrum as the output in the forward prediction improves the accuracy of the peak magnitude of CD prediction, avoids the introduction of auxiliary networks, and simplifies the network structure; The permutation importance analysis shows that the gold length of the resonator is the most critical structural parameter affecting the CD response. In the inverse design, the permutation importance method helps us to make feature selections for the input of the network. By reducing 251 inputs (the whole CD spectrum) to 4 inputs (the peak magnitude of CD and the corresponding wavelength), the network can still maintain a good prediction performance and decrease the training time of the network. Our proposed method can be extended not only to other DL models to study the CD response of chiral metamaterials but also to other areas where DL is combined with metamaterials to accelerate the system optimization and design process of nanophotonic devices.
","PeriodicalId":16833,"journal":{"name":"Journal of Physics D","volume":"34 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135567925","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}
Pub Date : 2023-10-20DOI: 10.1088/1361-6463/ad030a
Xiaozhi Zhan, Jialiang Li, Xiao Deng, Songwen Xiao, Yuan Sun, Sheng Cheng, He Bai, Tao Zhu
Abstract The interlayer coupling and magnetization reversal behaviors in NiFe/NiO/NiFe trilayers were investigated using polarized neutron reflectivity and Monte Carlo (MC) simulations. Our results reveal that the shape of NiFe loops transitions from square to tilted as the NiO thicknesses decrease, indicating changes in the direction of NiFe layer’s easy axis. This phenomenon can be attributed to variations occurring at NiO/NiFe interfaces for different NiO layer thicknesses. With thin NiO layer, interdiffusion at the NiO/NiFe interfaces leads to frustrated coupling, resulting in a noncollinear interlayer coupling. This observation is supported by MC simulations. Conversely, hardly any coupling frustration is observed for the sample with a thick NiO layer. Our findings propose a novel way to tailor the interlayer coupling through interface engineering.
{"title":"The noncollinear interlayer coupling in NiFe/NiO/NiFe trilayers","authors":"Xiaozhi Zhan, Jialiang Li, Xiao Deng, Songwen Xiao, Yuan Sun, Sheng Cheng, He Bai, Tao Zhu","doi":"10.1088/1361-6463/ad030a","DOIUrl":"https://doi.org/10.1088/1361-6463/ad030a","url":null,"abstract":"Abstract The interlayer coupling and magnetization reversal behaviors in NiFe/NiO/NiFe trilayers were investigated using polarized neutron reflectivity and Monte Carlo (MC) simulations. Our results reveal that the shape of NiFe loops transitions from square to tilted as the NiO thicknesses decrease, indicating changes in the direction of NiFe layer’s easy axis. This phenomenon can be attributed to variations occurring at NiO/NiFe interfaces for different NiO layer thicknesses. With thin NiO layer, interdiffusion at the NiO/NiFe interfaces leads to frustrated coupling, resulting in a noncollinear interlayer coupling. This observation is supported by MC simulations. Conversely, hardly any coupling frustration is observed for the sample with a thick NiO layer. Our findings propose a novel way to tailor the interlayer coupling through interface engineering.","PeriodicalId":16833,"journal":{"name":"Journal of Physics D","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135514438","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}
Abstract Ti3C2Tx MXene has attracted a considerable attention in energy devices, such as lithium-ion batteries and supercapacitors. This study investigated the effects of ultra-sonication and drying conditions on the structure and electrochemical performance of Ti3C2Tx MXene-based supercapacitor electrode, where a significant improvement in the super-capacitive behavior of the sample that was sonicated and vacuum-dried at 80°C has been observed. Ti3C2Tx nano-sheets were obtained by aluminum etching of Ti3AlC2 MAX-Phase followed by the rinsing and drying post-treatment to derive Ti3C2Tx MXene layers. The rinsed layers were then dried using 4 different conditions: 1- in the air at 25 ̊C, 2- in the air at 80 ̊C, 3- in a vacuum at 25 ̊C, 4- in a vacuum at 80 ̊C. It was observed that the specific capacitance at different scan rates of the vacuum-dried samples was, on average, 30% more than that of air-dried ones. Meanwhile, the samples dried at 80 ̊C have exhibited a 60% increase in the specific capacitance compared to the samples dried at 25 ̊C. Besides drying parameters, the effect of ultra-sonication of MXene layers on their electrochemical performance has also been investigated. Generally, the specific capacitance of delaminated layers was higher than that of non-delaminated ones. However, we have noticed that ultra-sonication deteriorates the capacitive stability of the samples over time. To further improve the supercapacitor electrodes, carbon coating was performed on the sample with the best electrochemical performance (sonicated and vacuum-dried at 80 ̊C), through a hydrothermal glucose decomposition method. The specific capacitance of the carbonized sample was 117.19 F/g at the scan rate of 2 mV/s, which is 35% more than that of the pristine MXene. The MXene structures were examined by FE-SEM, XRD, and FTIR and TGA analysis. The electrochemical characteristics of the electrodes were investigated via cyclic-voltammetry, charge-discharge test, and electrochemical Impedance spectroscopy.
{"title":"Effect of Ultra-Sonication, Vacuum Drying, and Carbon Coating on the Super-Capacitive Behavior of Ti3C2Tx MXene","authors":"Reza Azadvari, somayeh mohammadi, Alireza Habibi, Shayan Ahmadi, Zeinab Sanaee","doi":"10.1088/1361-6463/ad056c","DOIUrl":"https://doi.org/10.1088/1361-6463/ad056c","url":null,"abstract":"Abstract Ti3C2Tx MXene has attracted a considerable attention in energy devices, such as lithium-ion batteries and supercapacitors. This study investigated the effects of ultra-sonication and drying conditions on the structure and electrochemical performance of Ti3C2Tx MXene-based supercapacitor electrode, where a significant improvement in the super-capacitive behavior of the sample that was sonicated and vacuum-dried at 80°C has been observed. Ti3C2Tx nano-sheets were obtained by aluminum etching of Ti3AlC2 MAX-Phase followed by the rinsing and drying post-treatment to derive Ti3C2Tx MXene layers. The rinsed layers were then dried using 4 different conditions: 1- in the air at 25 ̊C, 2- in the air at 80 ̊C, 3- in a vacuum at 25 ̊C, 4- in a vacuum at 80 ̊C. It was observed that the specific capacitance at different scan rates of the vacuum-dried samples was, on average, 30% more than that of air-dried ones. Meanwhile, the samples dried at 80 ̊C have exhibited a 60% increase in the specific capacitance compared to the samples dried at 25 ̊C. Besides drying parameters, the effect of ultra-sonication of MXene layers on their electrochemical performance has also been investigated. Generally, the specific capacitance of delaminated layers was higher than that of non-delaminated ones. However, we have noticed that ultra-sonication deteriorates the capacitive stability of the samples over time. To further improve the supercapacitor electrodes, carbon coating was performed on the sample with the best electrochemical performance (sonicated and vacuum-dried at 80 ̊C), through a hydrothermal glucose decomposition method. The specific capacitance of the carbonized sample was 117.19 F/g at the scan rate of 2 mV/s, which is 35% more than that of the pristine MXene. The MXene structures were examined by FE-SEM, XRD, and FTIR and TGA analysis. The electrochemical characteristics of the electrodes were investigated via cyclic-voltammetry, charge-discharge test, and electrochemical Impedance spectroscopy.","PeriodicalId":16833,"journal":{"name":"Journal of Physics D","volume":"33 10","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135567799","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}
Pub Date : 2023-10-19DOI: 10.1088/1361-6463/ad015e
Bojin Lin, Hnin Lai Lai Aye, Kohei Ueno, Hiroshi Fujioka, Hideto Miyake, Yoshihiro Ishitani
The mid-infrared emission mechanism of line-and-space structures of metallic plates on dielectric materials is substantiated using high conductive n-doped (n++-) GaN–semi-insulating (SI-) GaN microstripe structures on an SI-GaN epitaxial layer, which was veiled when using line-and-space structures of Au plates. The present structure exhibits a few thermal emission lines originating from electric dipoles resonating with the coherent longitudinal optical (LO) phonon-like lattice vibration, which are formed by the local depolarization electric field in the surface n++-GaN/SI-GaN/n++-GaN regions. The energies of the LO-phonon-like modes shift from the original LO-phonon energy of GaN to the lower energy region, which contrasts with the LO-phonon resonant emission from the microstructures on GaAs. These emission lines have another notable feature, i.e. the observed peak energies are independent of the polar emission angle for both s- and p-polarizations, unlike the emissions by surface phonon polaritons showing a significant directive nature of peak energies. The results show that each peak energy of the present emission lines is positioned at the zero-point of the real part of the electric permittivity comprising the components of the transverse optical phonon and other electric dipoles induced by the LO-like modes, excluding the target mode. The significant peak-energy shift of the LO-like phonons is applicable to materials with wide Reststrahlen bands, which contrasts with that of the nearly LO-phonon resonating feature of materials with narrow Reststrahlen bands, such as GaAs. The peak energy shift depending on the emission direction is observed for Au–GaN stripe structures. This property is ascribed to the imperfect Au/GaN interface with surface states through the theoretical analysis of the modified electric permittivity in the surface region, numerical simulation of the local electric field via finite-difference time-domain calculation, and experimental studies on a Ti–GaN structure and emission peaks originating from an LO-like phonon of the α-Al2O3 substrate.
{"title":"Mid-infrared thermal radiation resonating with longitudinal-optical like phonon from n<sup>++</sup>-doped GaN–semi-insulating GaN grating structure","authors":"Bojin Lin, Hnin Lai Lai Aye, Kohei Ueno, Hiroshi Fujioka, Hideto Miyake, Yoshihiro Ishitani","doi":"10.1088/1361-6463/ad015e","DOIUrl":"https://doi.org/10.1088/1361-6463/ad015e","url":null,"abstract":"The mid-infrared emission mechanism of line-and-space structures of metallic plates on dielectric materials is substantiated using high conductive n-doped (n++-) GaN–semi-insulating (SI-) GaN microstripe structures on an SI-GaN epitaxial layer, which was veiled when using line-and-space structures of Au plates. The present structure exhibits a few thermal emission lines originating from electric dipoles resonating with the coherent longitudinal optical (LO) phonon-like lattice vibration, which are formed by the local depolarization electric field in the surface n++-GaN/SI-GaN/n++-GaN regions. The energies of the LO-phonon-like modes shift from the original LO-phonon energy of GaN to the lower energy region, which contrasts with the LO-phonon resonant emission from the microstructures on GaAs. These emission lines have another notable feature, i.e. the observed peak energies are independent of the polar emission angle for both s- and p-polarizations, unlike the emissions by surface phonon polaritons showing a significant directive nature of peak energies. The results show that each peak energy of the present emission lines is positioned at the zero-point of the real part of the electric permittivity comprising the components of the transverse optical phonon and other electric dipoles induced by the LO-like modes, excluding the target mode. The significant peak-energy shift of the LO-like phonons is applicable to materials with wide Reststrahlen bands, which contrasts with that of the nearly LO-phonon resonating feature of materials with narrow Reststrahlen bands, such as GaAs. The peak energy shift depending on the emission direction is observed for Au–GaN stripe structures. This property is ascribed to the imperfect Au/GaN interface with surface states through the theoretical analysis of the modified electric permittivity in the surface region, numerical simulation of the local electric field via finite-difference time-domain calculation, and experimental studies on a Ti–GaN structure and emission peaks originating from an LO-like phonon of the α-Al2O3 substrate.","PeriodicalId":16833,"journal":{"name":"Journal of Physics D","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135667715","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}
Pub Date : 2023-10-19DOI: 10.1088/1361-6463/acfe19
Baoping Ren, Chunhua Qin, Xuehui Guan, Kai-Da Xu
Abstract In this article, a newly spoof surface plasmon polaritons (SSPPs) is proposed and used to design a compact wideband bandpass filter (BPF). Different from the traditional SSPP unit cell with one-shaped structure, the unit cell of the proposed SSPPs consists of an H-shaped slotline and a bilateral T-shaped slotline. Benefiting from the hybrid structure, no transition portion is needed for impedance matching in the design of the microwave filter, which highly reduces the horizontal size of the SSPPs-based filter. The transition structure of microstrip to slotline provides a capacitance with a highpass frequency response, which enables the realization of a passband by cooperating with the natural lowpass property of SSPPs. Also, the upper and lower cutoff frequencies of the proposed filter can be adjusted independently by the key parameters. Besides, a wide upper stopband can be obtained by properly designing the SSPPs unit cell and the microstrip to slotline structure. Finally, a well-designed BPF operated at 1.3–6.2 GHz and its upper stopband rejection reaching 20 GHz is fabricated and measured. The test results are in good agreement with the simulations, which verifies the feasibility of the proposed structure and design method.
{"title":"Compact wideband filter with wide stopband using transition-free spoof surface plasmon polaritons","authors":"Baoping Ren, Chunhua Qin, Xuehui Guan, Kai-Da Xu","doi":"10.1088/1361-6463/acfe19","DOIUrl":"https://doi.org/10.1088/1361-6463/acfe19","url":null,"abstract":"Abstract In this article, a newly spoof surface plasmon polaritons (SSPPs) is proposed and used to design a compact wideband bandpass filter (BPF). Different from the traditional SSPP unit cell with one-shaped structure, the unit cell of the proposed SSPPs consists of an H-shaped slotline and a bilateral T-shaped slotline. Benefiting from the hybrid structure, no transition portion is needed for impedance matching in the design of the microwave filter, which highly reduces the horizontal size of the SSPPs-based filter. The transition structure of microstrip to slotline provides a capacitance with a highpass frequency response, which enables the realization of a passband by cooperating with the natural lowpass property of SSPPs. Also, the upper and lower cutoff frequencies of the proposed filter can be adjusted independently by the key parameters. Besides, a wide upper stopband can be obtained by properly designing the SSPPs unit cell and the microstrip to slotline structure. Finally, a well-designed BPF operated at 1.3–6.2 GHz and its upper stopband rejection reaching 20 GHz is fabricated and measured. The test results are in good agreement with the simulations, which verifies the feasibility of the proposed structure and design method.","PeriodicalId":16833,"journal":{"name":"Journal of Physics D","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135667009","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}
Pub Date : 2023-10-19DOI: 10.1088/1361-6463/ad024b
Afzal Ahmed, Qunsheng Cao, Muhammad Ismail Khan, Muhammad Sajjad, Fahad Ahmed
Abstract In this paper, a bi-layered ultra-thin multifunctional chiral metasurface is proposed to obtain asymmetric transmission (AT), cross-polarization conversion (CPC), and circular dichroism (CD). The multifunctional chiral metasurface realizes an AT with more than 70% efficiency over a Ku-band frequency range from 14.3 to 15.8 GHz, while in the operating frequency band from 13.5 to 16.2 GHz, the CPC ratio is above 90%. In addition, the metasurface exhibits CD in the K-band with a CD parameter of 0.6 at 24 GHz. Furthermore, the functionalities of AT and CPC are stable with changes in the incident angle of up to 60° for both transverse-electric and transverse-magnetic electromagnetic waves. For verification of the anticipated concept, the proposed chiral metasurface is fabricated and measured. The proposed design can be used for potential applications in the Ku- and K-bands for satellite communication and radar.
{"title":"An Ultra-thin Multifunctional Chiral Metasurface with Asymmetric Transmission, Cross-Polarization Conversion and Circular Dichroism for Ku and K-band Applications","authors":"Afzal Ahmed, Qunsheng Cao, Muhammad Ismail Khan, Muhammad Sajjad, Fahad Ahmed","doi":"10.1088/1361-6463/ad024b","DOIUrl":"https://doi.org/10.1088/1361-6463/ad024b","url":null,"abstract":"Abstract In this paper, a bi-layered ultra-thin multifunctional chiral metasurface is proposed to obtain asymmetric transmission (AT), cross-polarization conversion (CPC), and circular dichroism (CD). The multifunctional chiral metasurface realizes an AT with more than 70% efficiency over a Ku-band frequency range from 14.3 to 15.8 GHz, while in the operating frequency band from 13.5 to 16.2 GHz, the CPC ratio is above 90%. In addition, the metasurface exhibits CD in the K-band with a CD parameter of 0.6 at 24 GHz. Furthermore, the functionalities of AT and CPC are stable with changes in the incident angle of up to 60° for both transverse-electric and transverse-magnetic electromagnetic waves. For verification of the anticipated concept, the proposed chiral metasurface is fabricated and measured. The proposed design can be used for potential applications in the Ku- and K-bands for satellite communication and radar.","PeriodicalId":16833,"journal":{"name":"Journal of Physics D","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135667267","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}
Pub Date : 2023-10-18DOI: 10.1088/1361-6463/ad01c7
Hang Thi My Tran, Ngoc Linh Nguyen, Trung Kien Mac, Duc Anh Duong, Thien Thanh Nguyen, Anh-Tuan Duong, Hao Van Bui, Viet Huong NGUYEN
Abstract SnO 2 thin film is one of the most studied transparent conductive materials that can be deposited using vacuum-free techniques such as atmospheric pressure spatial atomic layer deposition (AP-SALD). This work studies SnO 2 thin films prepared from tin(II) acetylacetonate and water vapor, with a particular focus on the impact of air exposure during the AP-SALD process on the growth rate and electrical properties of the films. In-situ resistance measurements and ex-situ Hall effect characterization demonstrated that longer exposure time of the growing film surface to the open air ( t air ) at 240 °C led to conductivity degradation, while the film thickness decreases. The theoretical calculations show that −OH and O2dm (oxygen molecule adsorbed on the five-coordinated Sn atom, also called O 2 dimer) are the two most stable surface structures. The formation of O2dm is shown as the most thermodynamically favorable oxygen-related species on SnO 2 (110) surface formed when the film is exposed to the open air, giving rise to both the decrease of film thickness (associated with the desorption of −OH surface groups) and the increase of film resistivity versus t air . The optimized polycrystalline SnO 2 sample demonstrated relatively good electrical performance, including an electrical resistivity of 9.3 × 10 −3 Ω.cm, carrier density of 9.2 × 10 19 cm −3 , and Hall mobility of 7.3 cm 2 V −1 s −1 at a growth temperature as low as 240 °C. Our findings reveal the critical impact of processing in the open air on the electrical conductivity of the obtained SnO 2 films by AP-SALD coating technology.
{"title":"Impact of Air Exposure on Growth Rate and Electrical Properties of SnO<sub>2</sub> Thin Films by Atmospheric Pressure Spatial Atomic Layer Deposition","authors":"Hang Thi My Tran, Ngoc Linh Nguyen, Trung Kien Mac, Duc Anh Duong, Thien Thanh Nguyen, Anh-Tuan Duong, Hao Van Bui, Viet Huong NGUYEN","doi":"10.1088/1361-6463/ad01c7","DOIUrl":"https://doi.org/10.1088/1361-6463/ad01c7","url":null,"abstract":"Abstract SnO 2 thin film is one of the most studied transparent conductive materials that can be deposited using vacuum-free techniques such as atmospheric pressure spatial atomic layer deposition (AP-SALD). This work studies SnO 2 thin films prepared from tin(II) acetylacetonate and water vapor, with a particular focus on the impact of air exposure during the AP-SALD process on the growth rate and electrical properties of the films. In-situ resistance measurements and ex-situ Hall effect characterization demonstrated that longer exposure time of the growing film surface to the open air ( t air ) at 240 °C led to conductivity degradation, while the film thickness decreases. The theoretical calculations show that −OH and <?CDATA ${{text{O}}_2}^{{text{dm}}}$?> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" overflow=\"scroll\"> <mml:msup> <mml:mrow> <mml:msub> <mml:mrow> <mml:mtext>O</mml:mtext> </mml:mrow> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> <mml:mrow> <mml:mrow> <mml:mtext>dm</mml:mtext> </mml:mrow> </mml:mrow> </mml:msup> </mml:math> (oxygen molecule adsorbed on the five-coordinated Sn atom, also called O 2 dimer) are the two most stable surface structures. The formation of <?CDATA ${{text{O}}_2}^{{text{dm}}}$?> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" overflow=\"scroll\"> <mml:msup> <mml:mrow> <mml:msub> <mml:mrow> <mml:mtext>O</mml:mtext> </mml:mrow> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> <mml:mrow> <mml:mrow> <mml:mtext>dm</mml:mtext> </mml:mrow> </mml:mrow> </mml:msup> </mml:math> is shown as the most thermodynamically favorable oxygen-related species on SnO 2 (110) surface formed when the film is exposed to the open air, giving rise to both the decrease of film thickness (associated with the desorption of −OH surface groups) and the increase of film resistivity versus t air . The optimized polycrystalline SnO 2 sample demonstrated relatively good electrical performance, including an electrical resistivity of 9.3 × 10 −3 Ω.cm, carrier density of 9.2 × 10 19 cm −3 , and Hall mobility of 7.3 cm 2 V −1 s −1 at a growth temperature as low as 240 °C. Our findings reveal the critical impact of processing in the open air on the electrical conductivity of the obtained SnO 2 films by AP-SALD coating technology.","PeriodicalId":16833,"journal":{"name":"Journal of Physics D","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135824328","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}
Pub Date : 2023-10-18DOI: 10.1088/1361-6463/ad0478
Lingling Chu, Chao Xu, Duanwangde Liu, Chao Nie, Liting Deng
Abstract In this paper, a performance-enhanced hybrid ultraviolet metal-semiconductor-metal (MSM) photodetector (UVPD) has been produced. This device incorporates a mixed photosensitive layer consisting of MXene nanoflakes that are covered on a thin film formed by Ag nanowires (NWs) wrapped in ZnO nanoparticles (NPs). This configuration, referred to as ZnO@Ag NWs/Mxene, capitalizes on the hot electrons generated by the Localized Surface Plasmon Resonance (LSPR) phenomenon occurring in the Ag NWs and MXene. These hot electrons possess sufficient energy to traverse the interface depletion layer and reach the ZnO layer. Therefore, the injected hot electrons serve as additional photo carriers in the ZnO layer, thereby increasing the number of photo-generated carriers and improving the carrier concentration in ZnO. The improved UVPD device exhibits an amplified photocurrent of ~ 2499.35 nA at 5 V, under a light intensity of 6.52 mW/cm2 and a wavelength of 365 nm. Simultaneously, it achieves enhanced performance indices, including an On/Off Ratio of ~ 984.19, a responsivity (Rp) of ~ 66.87 mA/W, and a detectivity (D*) of ~ 1.82 × 1011 jones. These values represent a significant improvement compared to devices based solely on the ZnO configuration, with enhancements of ~ 24.90, 3.93, 23.38, and 9.33 times, respectively. Based on the obtained results, it can be inferred that employing the hot electron injection effect to design and enhance the performance of optoelectronic devices based on wide band gap semiconductors is a reasonable and effective strategy.
{"title":"Plasmon-induced Hot-electron Injection Effect: Mechanism of Performance Enhancement for ZnO MSM Hybrid Photodetector by Introducing Ag NWs and MXene","authors":"Lingling Chu, Chao Xu, Duanwangde Liu, Chao Nie, Liting Deng","doi":"10.1088/1361-6463/ad0478","DOIUrl":"https://doi.org/10.1088/1361-6463/ad0478","url":null,"abstract":"Abstract In this paper, a performance-enhanced hybrid ultraviolet metal-semiconductor-metal (MSM) photodetector (UVPD) has been produced. This device incorporates a mixed photosensitive layer consisting of MXene nanoflakes that are covered on a thin film formed by Ag nanowires (NWs) wrapped in ZnO nanoparticles (NPs). This configuration, referred to as ZnO@Ag NWs/Mxene, capitalizes on the hot electrons generated by the Localized Surface Plasmon Resonance (LSPR) phenomenon occurring in the Ag NWs and MXene. These hot electrons possess sufficient energy to traverse the interface depletion layer and reach the ZnO layer. Therefore, the injected hot electrons serve as additional photo carriers in the ZnO layer, thereby increasing the number of photo-generated carriers and improving the carrier concentration in ZnO. The improved UVPD device exhibits an amplified photocurrent of ~ 2499.35 nA at 5 V, under a light intensity of 6.52 mW/cm2 and a wavelength of 365 nm. Simultaneously, it achieves enhanced performance indices, including an On/Off Ratio of ~ 984.19, a responsivity (Rp) of ~ 66.87 mA/W, and a detectivity (D*) of ~ 1.82 × 1011 jones. These values represent a significant improvement compared to devices based solely on the ZnO configuration, with enhancements of ~ 24.90, 3.93, 23.38, and 9.33 times, respectively. Based on the obtained results, it can be inferred that employing the hot electron injection effect to design and enhance the performance of optoelectronic devices based on wide band gap semiconductors is a reasonable and effective strategy.","PeriodicalId":16833,"journal":{"name":"Journal of Physics D","volume":"203 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135825505","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}
Pub Date : 2023-10-18DOI: 10.1088/1361-6463/ad005d
Min Wang, Gao Wei, Kangkang Han, Siyuan Lei
Abstract In this paper, a leaky wave antenna (LWA) based on even mode excited spoof surface plasmon polaritons (SSPPs) is proposed. The LWA can radiate beams from backfire to endfire as the frequency increases. The proposed LWA is asymmetrically modulated by the method of sinusoidal modulation of the reactance surface at two sides of the SSPP structure, which brings a phase difference between two sides of the antenna. The phase difference produces the field component that radiates the beam in the backfire or endfire direction. In this way, the full-angle beam scanning is realized. Moreover, to reduce the open-stop band effect, an improved LWA with multiperiod modulation and asymmetric units is proposed. The simulated results indicate that the radiation beam steers from backfire to endfire. A prototype of the proposed LWAs is fabricated and measured. The measured results agree well with the simulated ones.
{"title":"Leaky wave antenna with backfire to endfire beam-scanning capability based on even mode spoof surface plasmon polaritons","authors":"Min Wang, Gao Wei, Kangkang Han, Siyuan Lei","doi":"10.1088/1361-6463/ad005d","DOIUrl":"https://doi.org/10.1088/1361-6463/ad005d","url":null,"abstract":"Abstract In this paper, a leaky wave antenna (LWA) based on even mode excited spoof surface plasmon polaritons (SSPPs) is proposed. The LWA can radiate beams from backfire to endfire as the frequency increases. The proposed LWA is asymmetrically modulated by the method of sinusoidal modulation of the reactance surface at two sides of the SSPP structure, which brings a phase difference between two sides of the antenna. The phase difference produces the field component that radiates the beam in the backfire or endfire direction. In this way, the full-angle beam scanning is realized. Moreover, to reduce the open-stop band effect, an improved LWA with multiperiod modulation and asymmetric units is proposed. The simulated results indicate that the radiation beam steers from backfire to endfire. A prototype of the proposed LWAs is fabricated and measured. The measured results agree well with the simulated ones.","PeriodicalId":16833,"journal":{"name":"Journal of Physics D","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135823872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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