Pub Date : 2024-04-25DOI: 10.1088/1361-6463/ad4370
Kai Guo, Duo Yang, Bingyi Liu, Zhongyi Guo
Metasurface based micro-spectrometer presents a promising avenue for achieving compact, lightweight, and cost-effective solutions for miniaturization of hyperspectral imaging systems. Nevertheless, this type of design encounter limitations primarily due to constrained manipulation mechanism of light field, resulting in high cross-correlation among transmission spectra and imperfect reconstructed images. In this paper, we propose and numerically demonstrate a micro-spectrometer based on metasurface combined with multilayer thin films, whose spectral response improves performance for application, i.e. achieving low spectral cross-correlation. Additionally, we incorporate particle swarm optimization with compressed sensing algorithm to optimize the proposed micro-spectrometer. This approach effectively reconstructs both narrowband and broadband hyperspectral signals with minimal error, achieving an impressive 2nm spectral resolution. The simulation results of hyperspectral imaging demonstrated that the proposed methodology successfully reconstructs broadband hyperspectral images with an average spectral fidelity of 91.42%. This method holds significant potential for integrating into smartphones and other portable spectrometers, advancing the design of compact hyperspectral imaging systems.
{"title":"Random broadband filters based on combination of metasurface and multilayer thin films for hyperspectral imaging","authors":"Kai Guo, Duo Yang, Bingyi Liu, Zhongyi Guo","doi":"10.1088/1361-6463/ad4370","DOIUrl":"https://doi.org/10.1088/1361-6463/ad4370","url":null,"abstract":"\u0000 Metasurface based micro-spectrometer presents a promising avenue for achieving compact, lightweight, and cost-effective solutions for miniaturization of hyperspectral imaging systems. Nevertheless, this type of design encounter limitations primarily due to constrained manipulation mechanism of light field, resulting in high cross-correlation among transmission spectra and imperfect reconstructed images. In this paper, we propose and numerically demonstrate a micro-spectrometer based on metasurface combined with multilayer thin films, whose spectral response improves performance for application, i.e. achieving low spectral cross-correlation. Additionally, we incorporate particle swarm optimization with compressed sensing algorithm to optimize the proposed micro-spectrometer. This approach effectively reconstructs both narrowband and broadband hyperspectral signals with minimal error, achieving an impressive 2nm spectral resolution. The simulation results of hyperspectral imaging demonstrated that the proposed methodology successfully reconstructs broadband hyperspectral images with an average spectral fidelity of 91.42%. This method holds significant potential for integrating into smartphones and other portable spectrometers, advancing the design of compact hyperspectral imaging systems.","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140656320","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 : 2024-04-25DOI: 10.1088/1361-6463/ad436d
Takeru Hato, Kaishu Nitta, H. Muneoka, Yoshiki Shimizu, Kazuo Terashima, Tsuyohito Ito
Zinc oxide (ZnO) and its composite particles with controlled sizes, shapes, compositions, and physical and chemical properties are required for a wide variety of applications. In this study, we report a simple method for synthesising ZnO and ZnO/Ag composite particles via atmospheric-pressure plasma processing using inkjet droplets. Depending on the initial solution concentration, ZnO particles containing voids, with average sizes ranging from submicrons to several microns can be synthesised. Energy dispersive X-ray spectroscopy measurements of the synthesised ZnO/Ag particles suggest that the molar ratio of Ag to Zn in the initial solution was retained in the synthesised particles. A high surface-enhanced Raman scattering effect was observed in the particles synthesised from the solution with an Ag molar ratio of 50 % to the total solute. The proposed method enables the synthesis of ZnO particles of various sizes, microstructures, compositions and optical properties with relatively narrow size distributions.
氧化锌（ZnO）及其复合颗粒的尺寸、形状、成分、物理和化学性质都需要进行控制，以满足各种应用的需要。在本研究中，我们报告了一种利用喷墨液滴通过常压等离子处理合成氧化锌和氧化锌/银复合粒子的简单方法。根据初始溶液浓度的不同，可以合成平均尺寸从亚微米到几微米不等的含有空隙的氧化锌颗粒。对合成的氧化锌/银颗粒进行的能量色散 X 射线光谱测量表明，合成颗粒中保留了初始溶液中银与锌的摩尔比。在银与总溶质摩尔比为 50% 的溶液中合成的颗粒中观察到了较高的表面增强拉曼散射效应。所提出的方法能够合成各种尺寸、微观结构、成分和光学特性的氧化锌颗粒，且尺寸分布相对较窄。
{"title":"Synthesis of ZnO and ZnO/Ag fine particles by plasma-assisted inkjet processing","authors":"Takeru Hato, Kaishu Nitta, H. Muneoka, Yoshiki Shimizu, Kazuo Terashima, Tsuyohito Ito","doi":"10.1088/1361-6463/ad436d","DOIUrl":"https://doi.org/10.1088/1361-6463/ad436d","url":null,"abstract":"\u0000 Zinc oxide (ZnO) and its composite particles with controlled sizes, shapes, compositions, and physical and chemical properties are required for a wide variety of applications. In this study, we report a simple method for synthesising ZnO and ZnO/Ag composite particles via atmospheric-pressure plasma processing using inkjet droplets. Depending on the initial solution concentration, ZnO particles containing voids, with average sizes ranging from submicrons to several microns can be synthesised. Energy dispersive X-ray spectroscopy measurements of the synthesised ZnO/Ag particles suggest that the molar ratio of Ag to Zn in the initial solution was retained in the synthesised particles. A high surface-enhanced Raman scattering effect was observed in the particles synthesised from the solution with an Ag molar ratio of 50 % to the total solute. The proposed method enables the synthesis of ZnO particles of various sizes, microstructures, compositions and optical properties with relatively narrow size distributions.","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140653321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A novel flexible composite fabric has been engineered by combining piezoelectric poly (vinylidene fluoride) (PVDF) and tetrapod zinc oxide (T-ZnO) nanostructures, which are integrated onto a nonwoven fabric substrate. This fabric exhibits a wide array of functionalities, notably self-cleaning and antibacterial properties, facilitated by the synergistic piezo-photocatalytic coupling effect. Through the utilization of the piezoelectric effect inherent in PVDF/T-ZnO in tandem with the photocatalytic attributes of T-ZnO nanostructures, the fabric achieves concurrent degradation of organic pollutants and antibacterial efficacy when exposed to mechanical vibration and solar irradiation. The piezo-photocatalytic coupling effect engenders an internal electric field that aids in the effective separation of photo-generated carriers (electrons and holes), thereby diminishing recombination rates and augmenting the efficiency of the photocatalytic degradation process. Notably, organic pollutants such as methylene blue and azithromycin exhibit degradation levels of 96.0% and 92.6%, respectively, within a timeframe of 25 and 60 minutes. The incorporation of PVDF/T-ZnO results in an approximate 40% enhancement in the degradation rate of organic substances compared to the use of T-ZnO in isolation. Furthermore, the composite fabric showcases exceptional antibacterial efficacy, effectively inhibiting the proliferation of Staphylococcus aureus. Experimental findings reveal that the average antibacterial zone diameter of the PVDF/T-ZnO fabric measures at 7.68 mm, significantly surpassing that of the T-ZnO fabric and nonwoven fabric. Given its remarkable self-cleaning and antibacterial attributes, the PVDF/T-ZnO fabric exhibits substantial potential for diverse applications, including the development of intelligent masks tailored for deployment in healthcare settings and polluted environments.
{"title":"A flexible self-cleaning/antibacterial PVDF/T-ZnO fabric based on piezo-photocatalytic coupling effect for smart mask","authors":"Qihao Li, Rui Lin, Zhaoxiang Tang, Shan Liang, X. Xue, Lili Xing","doi":"10.1088/1361-6463/ad4368","DOIUrl":"https://doi.org/10.1088/1361-6463/ad4368","url":null,"abstract":"\u0000 A novel flexible composite fabric has been engineered by combining piezoelectric poly (vinylidene fluoride) (PVDF) and tetrapod zinc oxide (T-ZnO) nanostructures, which are integrated onto a nonwoven fabric substrate. This fabric exhibits a wide array of functionalities, notably self-cleaning and antibacterial properties, facilitated by the synergistic piezo-photocatalytic coupling effect. Through the utilization of the piezoelectric effect inherent in PVDF/T-ZnO in tandem with the photocatalytic attributes of T-ZnO nanostructures, the fabric achieves concurrent degradation of organic pollutants and antibacterial efficacy when exposed to mechanical vibration and solar irradiation. The piezo-photocatalytic coupling effect engenders an internal electric field that aids in the effective separation of photo-generated carriers (electrons and holes), thereby diminishing recombination rates and augmenting the efficiency of the photocatalytic degradation process. Notably, organic pollutants such as methylene blue and azithromycin exhibit degradation levels of 96.0% and 92.6%, respectively, within a timeframe of 25 and 60 minutes. The incorporation of PVDF/T-ZnO results in an approximate 40% enhancement in the degradation rate of organic substances compared to the use of T-ZnO in isolation. Furthermore, the composite fabric showcases exceptional antibacterial efficacy, effectively inhibiting the proliferation of Staphylococcus aureus. Experimental findings reveal that the average antibacterial zone diameter of the PVDF/T-ZnO fabric measures at 7.68 mm, significantly surpassing that of the T-ZnO fabric and nonwoven fabric. Given its remarkable self-cleaning and antibacterial attributes, the PVDF/T-ZnO fabric exhibits substantial potential for diverse applications, including the development of intelligent masks tailored for deployment in healthcare settings and polluted environments.","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140657345","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 : 2024-04-25DOI: 10.1088/1361-6463/ad436e
Hui Zeng, Meng Wu, Chao Ma, Xi Fu, Haixia Gao
Two-dimensional (2D) semiconductors have shown great prospect in future-oriented optoelectronic applications, whereas the applications of conventional 2D materials are significantly impeded by the low electron mobility (≤ 200 cm2V1s1). In this work, strain mediated fluorine and hydrogen passivated 2D Ga2O3 systems (FGa2O3H) have been explored via using first-principles calculations with the Heyd-Scuseria-Ernzerh (HSE) and Perdew-Burke-Ernzerhof (PBE) functional. Our results reveal a considerable high electron mobility of FGa2O3H up to 4863.05 cm2V1s1 as the uniaxial tensile strain reaches 6%, which can be attributed to the enhanced overlapping of wave functions and bonding features. Overall, applying the uniaxial strain monotonously along a(b) direction from compressive to tensile cases, the bandgaps of 2D FGa2O3H increase initially and then decrease, which is originated from the changes of σ* anti-bonding in the CBM and π bonding states in the VBM accompanying with the lengthening Ga-O bonds. Additionally, when the tensile strain is larger than 8%, the stronger π bonding at G point leads to an indirect-to-direct transition. Besides the highest electron mobility of n-type doped 2D FGa2O3H with 6% tensile strain, the electrical conductivity is enhanced and further elevated with the temperature increase from 300K to 800K. The variations of the absorption coefficient in the ultraviolet region is negligible with the increasing tensile strain from 0% to 6%, shed light on its applications in high-power optoelectronic devices.
{"title":"Tunable Electronic, Transport, and Optical Properties of Fluorine and Hydrogen Passivated Two-Dimensional Ga2O3 by Uniaxial Strain","authors":"Hui Zeng, Meng Wu, Chao Ma, Xi Fu, Haixia Gao","doi":"10.1088/1361-6463/ad436e","DOIUrl":"https://doi.org/10.1088/1361-6463/ad436e","url":null,"abstract":"\u0000 Two-dimensional (2D) semiconductors have shown great prospect in future-oriented optoelectronic applications, whereas the applications of conventional 2D materials are significantly impeded by the low electron mobility (≤ 200 cm2V1s1). In this work, strain mediated fluorine and hydrogen passivated 2D Ga2O3 systems (FGa2O3H) have been explored via using first-principles calculations with the Heyd-Scuseria-Ernzerh (HSE) and Perdew-Burke-Ernzerhof (PBE) functional. Our results reveal a considerable high electron mobility of FGa2O3H up to 4863.05 cm2V1s1 as the uniaxial tensile strain reaches 6%, which can be attributed to the enhanced overlapping of wave functions and bonding features. Overall, applying the uniaxial strain monotonously along a(b) direction from compressive to tensile cases, the bandgaps of 2D FGa2O3H increase initially and then decrease, which is originated from the changes of σ* anti-bonding in the CBM and π bonding states in the VBM accompanying with the lengthening Ga-O bonds. Additionally, when the tensile strain is larger than 8%, the stronger π bonding at G point leads to an indirect-to-direct transition. Besides the highest electron mobility of n-type doped 2D FGa2O3H with 6% tensile strain, the electrical conductivity is enhanced and further elevated with the temperature increase from 300K to 800K. The variations of the absorption coefficient in the ultraviolet region is negligible with the increasing tensile strain from 0% to 6%, shed light on its applications in high-power optoelectronic devices.","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140657308","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}
To achieve spectrum flattening in the wavelength division multiplexing (WDM) device's arrayed waveguide grating (AWG), we have cascaded a special "A" shape multimode interference (MMI) structure at the end of the input waveguide. The MMI is designed by the linear spreading function (LSF), which increases the 1 dB bandwidth to 0.7 nm and the 3 dB bandwidth to 1.6 0.2 nm, the insertion loss is measured at 3.5±0.3 dB, and the channel crosstalk is below -30 dB.
为了在波分复用（WDM）设备的阵列波导光栅（AWG）中实现频谱平坦化，我们在输入波导的末端级联了一个特殊的 "A "形多模干涉（MMI）结构。MMI 采用线性展宽函数（LSF）设计，将 1 dB 带宽提高到 0.7 nm，3 dB 带宽提高到 1.6 0.2 nm，插入损耗测量值为 3.5±0.3 dB，信道串扰低于 -30 dB。
{"title":"A flat-top Arrayed Waveguide Grating base on cascading \"A\" shape Multimode Interference","authors":"Kanglu Zhou, Xiaochun Liu, Jialiang Zhang, Changshui Chen","doi":"10.1088/1361-6463/ad4372","DOIUrl":"https://doi.org/10.1088/1361-6463/ad4372","url":null,"abstract":"\u0000 To achieve spectrum flattening in the wavelength division multiplexing (WDM) device's arrayed waveguide grating (AWG), we have cascaded a special \"A\" shape multimode interference (MMI) structure at the end of the input waveguide. The MMI is designed by the linear spreading function (LSF), which increases the 1 dB bandwidth to 0.7 nm and the 3 dB bandwidth to 1.6 0.2 nm, the insertion loss is measured at 3.5±0.3 dB, and the channel crosstalk is below -30 dB.","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140654432","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 : 2024-04-25DOI: 10.1088/1361-6463/ad4366
Lijun Wang, Huan Zhao, Jie Liu, Wei Li
CF4 is an important source of reactive F-containing species (RFS) so that it is used to mix with inert gas as the working gas of atmospheric pressure plasma jet (APPJ) for material surface fluoridation modification. The addition of a small amount of O2 can increase the density of RFS in He/CF4 APPJ. Therefore, the hydrodynamic, electrical and optical properties of He/CF4/O2 APPJ interacting with the dielectric are experimentally investigated in this paper. Meanwhile, the influence of the excitation source on plasma discharge is discussed in detail and the internal mechanism of the experimental phenomenon in this paper is analyzed using the simulation results based on the model established in the previous paper. It is found that the addition of a small amount of O2 can increase the intensity and accelerate the axial propagation speed of He/CF4 APPJ due to the low ionization energy of O2 and the increase of the Penning ionization between metastable He and O2. With the increase of O2 content, the stability of the discharge is gradually enhanced due to the electron attachment reaction of O2 and the position of the primary current pulse in each half voltage cycle gradually approaches the position of the peak voltage because the increase in O2 content raises the breakdown threshold in dielectric barrier discharge (DBD) region. In the presence of downstream dielectric, the addition of 0.1%O2 does not significantly change the radial development radius of APPJ due to the higher electron attachment rate and electron collision excitation loss power. The discharge pulse intensity is generally reduced compared to the absence of dielectric and the glow discharge in the strict sense no longer exists. The continuous spectrum intensity of RFS increases with the addition of a small amount of O2 while decreases significantly when O2 content is too high.
{"title":"Experimental study of the influence of O2 content on electrical and optical characteristics of He/CF4 APPJ","authors":"Lijun Wang, Huan Zhao, Jie Liu, Wei Li","doi":"10.1088/1361-6463/ad4366","DOIUrl":"https://doi.org/10.1088/1361-6463/ad4366","url":null,"abstract":"\u0000 CF4 is an important source of reactive F-containing species (RFS) so that it is used to mix with inert gas as the working gas of atmospheric pressure plasma jet (APPJ) for material surface fluoridation modification. The addition of a small amount of O2 can increase the density of RFS in He/CF4 APPJ. Therefore, the hydrodynamic, electrical and optical properties of He/CF4/O2 APPJ interacting with the dielectric are experimentally investigated in this paper. Meanwhile, the influence of the excitation source on plasma discharge is discussed in detail and the internal mechanism of the experimental phenomenon in this paper is analyzed using the simulation results based on the model established in the previous paper. It is found that the addition of a small amount of O2 can increase the intensity and accelerate the axial propagation speed of He/CF4 APPJ due to the low ionization energy of O2 and the increase of the Penning ionization between metastable He and O2. With the increase of O2 content, the stability of the discharge is gradually enhanced due to the electron attachment reaction of O2 and the position of the primary current pulse in each half voltage cycle gradually approaches the position of the peak voltage because the increase in O2 content raises the breakdown threshold in dielectric barrier discharge (DBD) region. In the presence of downstream dielectric, the addition of 0.1%O2 does not significantly change the radial development radius of APPJ due to the higher electron attachment rate and electron collision excitation loss power. The discharge pulse intensity is generally reduced compared to the absence of dielectric and the glow discharge in the strict sense no longer exists. The continuous spectrum intensity of RFS increases with the addition of a small amount of O2 while decreases significantly when O2 content is too high.","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140658442","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}
Electromagnetic multipole resonance can be excited by dielectric nanostructures of appropriate size to effectively promote light-matter interaction. The interactions between light and nanostructures have the capability to enhance the electromagnetic field in the near field, thereby improving the nonlinear effect of nanostructures. We illustrate that the supercavity mode and magnetic dipole resonance are activated by a single dumbbell-shaped silicon nanoblock (DS-SiNB), to trap the near-field electromagnetic field energy. Enhanced second harmonic generation is achieved by exploiting the localized electromagnetic field at the surface of the nanostructure. Numerical simulations reveal that magnetic quadrupole (MQ) and total electric dipole (TED) can be coupled to the same radiation channel by adjusting continuously the aspect ratio Lout/Ly (the outer edge length to the length of DS-SiNB) of the nanoblock. When the aspect ratio Lout/Ly = 1, the supercavity mode formed by the interference of MQ and TED is excited at λ1 = 1124 nm. And, the strong magnetic resonance mode formed by the coupling of two magnetic dipoles (MD) in the same direction is also excited at λ2 = 1124 nm. Supercavity mode and strong magnetic dipole resonance can effectively capture electromagnetic fields on the surface of nanostructures to attain enhanced second harmonic generation (SHG). Our study presents a novel approach to enhance the nonlinear optical effect of a single silicon nanostructure, which can lead to the development of more efficient nonlinear optical devices.
{"title":"Enhanced second harmonic generation from supercavity mode and magnetic resonance in dumbbell-shaped silicon nanoblock","authors":"Yuwei Yuan, Yunbao Zheng, Ouyang Min, Haihua Fan, Qiaofeng Dai, Haiying Liu, Li-Jun Wu","doi":"10.1088/1361-6463/ad436f","DOIUrl":"https://doi.org/10.1088/1361-6463/ad436f","url":null,"abstract":"\u0000 Electromagnetic multipole resonance can be excited by dielectric nanostructures of appropriate size to effectively promote light-matter interaction. The interactions between light and nanostructures have the capability to enhance the electromagnetic field in the near field, thereby improving the nonlinear effect of nanostructures. We illustrate that the supercavity mode and magnetic dipole resonance are activated by a single dumbbell-shaped silicon nanoblock (DS-SiNB), to trap the near-field electromagnetic field energy. Enhanced second harmonic generation is achieved by exploiting the localized electromagnetic field at the surface of the nanostructure. Numerical simulations reveal that magnetic quadrupole (MQ) and total electric dipole (TED) can be coupled to the same radiation channel by adjusting continuously the aspect ratio Lout/Ly (the outer edge length to the length of DS-SiNB) of the nanoblock. When the aspect ratio Lout/Ly = 1, the supercavity mode formed by the interference of MQ and TED is excited at λ1 = 1124 nm. And, the strong magnetic resonance mode formed by the coupling of two magnetic dipoles (MD) in the same direction is also excited at λ2 = 1124 nm. Supercavity mode and strong magnetic dipole resonance can effectively capture electromagnetic fields on the surface of nanostructures to attain enhanced second harmonic generation (SHG). Our study presents a novel approach to enhance the nonlinear optical effect of a single silicon nanostructure, which can lead to the development of more efficient nonlinear optical devices.","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140658452","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 : 2024-04-25DOI: 10.1088/1361-6463/ad436b
Shravani Kale, Dhanashree Sable, Rajat Srivastava, Vaishali Phatak Londhe, S. Kale
MXene Ti3C2Tx (with 30% HF-etched, named Ti3C2Tx-30) plays a pivotal role in the substantial enhancement of the structural modification of molybdenum trioxide (MoO3). Additionally, as the surface MoO3 molecules come in contact with reducing gas moieties, they actively participate in gas sensing at room temperature. The percentage of Ti3C2Tx-30 in the MoO3 matrix was varied as 10%, 20%, and 40%, denoted as MM-10, MM-20, and MM-40, respectively. Structural analysis confirmed the composition of the basic elements, and evolution of TiO2 at higher percentage of Ti3C2Tx-30. Spectroscopy analysis shows the interactions between Ti3C2Tx-30 and MoO3, showcasing work functions of 6.91 eV, 6.75 eV, and 7.21 eV for MM-10, MM-20, and MM-40, respectively, confirming the MM-20 to be an optimum composition. When the samples were exposed to ammonia gas, MM-20 showed high response (93% for 100 ppm) at room temperature, with the response time ~ 10 s. As compared to bare MoO3 these samples showed ten-fold improvement. The excess electrons on the surface of Ti3C2Tx-30 facilitate the formation of O2- species, which also provides stability to the, otherwise-highly-reactive, MXene surface. These species actively react with ammonia molecules in the presence of adsorbed MoO3, thereby changing the resistance of the system. This can be a significant step towards imparting high gas sensitivity to metal oxides at room temperature via incorporation of optimum percentage of optimised Ti3C2Tx.
{"title":"Synergistic combination of 2-D MXene and MoO3 nanoparticles for improved gas sensing at room temperature","authors":"Shravani Kale, Dhanashree Sable, Rajat Srivastava, Vaishali Phatak Londhe, S. Kale","doi":"10.1088/1361-6463/ad436b","DOIUrl":"https://doi.org/10.1088/1361-6463/ad436b","url":null,"abstract":"\u0000 MXene Ti3C2Tx (with 30% HF-etched, named Ti3C2Tx-30) plays a pivotal role in the substantial enhancement of the structural modification of molybdenum trioxide (MoO3). Additionally, as the surface MoO3 molecules come in contact with reducing gas moieties, they actively participate in gas sensing at room temperature. The percentage of Ti3C2Tx-30 in the MoO3 matrix was varied as 10%, 20%, and 40%, denoted as MM-10, MM-20, and MM-40, respectively. Structural analysis confirmed the composition of the basic elements, and evolution of TiO2 at higher percentage of Ti3C2Tx-30. Spectroscopy analysis shows the interactions between Ti3C2Tx-30 and MoO3, showcasing work functions of 6.91 eV, 6.75 eV, and 7.21 eV for MM-10, MM-20, and MM-40, respectively, confirming the MM-20 to be an optimum composition. When the samples were exposed to ammonia gas, MM-20 showed high response (93% for 100 ppm) at room temperature, with the response time ~ 10 s. As compared to bare MoO3 these samples showed ten-fold improvement. The excess electrons on the surface of Ti3C2Tx-30 facilitate the formation of O2- species, which also provides stability to the, otherwise-highly-reactive, MXene surface. These species actively react with ammonia molecules in the presence of adsorbed MoO3, thereby changing the resistance of the system. This can be a significant step towards imparting high gas sensitivity to metal oxides at room temperature via incorporation of optimum percentage of optimised Ti3C2Tx.","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140656261","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 : 2024-04-25DOI: 10.1088/1361-6463/ad4369
Tongxin Ge, Haoming Wei, Yangqing Wu, Tengzhou Yang, Bingqiang Cao
High-quality epitaxial BiFeO3 (BFO) films were grown on (001)-, (110)-, and (111)-oriented Nb:SrTiO3 (NSTO) substrates by pulsed laser deposition. The types of domain structures can be modulated by BFO ferroelectric films with different crystalline orientations. The ON/OFF ratios are 6E3, 3E4 and 2E5 obtained in (001)-, (110)-, and (111)-oriented Au/BFO/NSTO ferroelectric tunnel junctions (FTJs), respectively. The analysis of the I-V curves of tunneling current and average BFO ferroelectric barrier height prove that the polarization intensity of the BFO films modulate both ferroelectric barrier and Schottky barrier profile, which further influences the electronic tunneling probability in the BFO FTJs. This work will be useful for further study on achieving giant ON/OFF ratio and developing insights on the barrier profile and transport mechanism of MFS-type FTJs.
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Pub Date : 2024-04-25DOI: 10.1088/1361-6463/ad436c
Lise Watrin, François Silva, Cyril Jadaud, P. Bulkin, J. Vanel, Dominique Muller, Erik V Johnson, Karim Ouaras, P. Roca i Cabarrocas
We report on low-temperature (500°C) and low-pressure (0.3 mbar) direct growth of GaN thin films on silicon (100) substrates using Remote Plasma Chemical Vapor Deposition (RP-CVD). In the custom-designed reactor, an RF Inductively Coupled Plasma (ICP) is generated remotely from the substrate's area to facilitate the decomposition of group-V precursor, N2 with added H2, while group-III precursor Trimethylgallium (TMGa), is directly injected into the growth chamber mixed with H2 carrier gas. Growth parameters such as RF power, process pressure and gas flow rates have been optimized to achieve a film growth rate of about 0.6 µm/h. Several characterization techniques were used to investigate the plasma and the properties of the grown thin films in terms of their crystallinity, morphology, topography, and composition. The films are highly textured with a preferential orientation along the c-axis of the wurtzite structure. They present a small roughness in the nanometer range and a columnar microstructure with a grain size of one hundred nanometers, and a gallium polarity (+c plane oriented). RBS and NRA analysis show that the chemical composition is homogeneous through the depth of the layer, with a III/V ratio close to 1, a very low content of oxygen (below the detection limit ~1%) and a carbon content up to 11%. It was shown that that the increase of plasma power helps to reduce this carbon contamination down to 8%. This research paves the way for a growth method compatible with cost reduction of III-V thin film production achieved through reduced gas consumption facilitated by RP-CVD operation at low pressure.
我们报告了利用远程等离子体化学气相沉积（RP-CVD）技术在硅（100）基底上低温（500°C）、低压（0.3 毫巴）直接生长 GaN 薄膜的情况。在定制设计的反应器中，射频电感耦合等离子体 (ICP) 在远离基底区域的地方产生，以促进 V 族前驱体 N2 与添加的 H2 的分解，而 III 族前驱体三甲基镓 (TMGa) 则与 H2 载气混合直接注入生长室。对射频功率、工艺压力和气体流速等生长参数进行了优化，以达到约 0.6 µm/h 的薄膜生长速度。我们使用了多种表征技术来研究等离子体和生长薄膜在结晶度、形态、形貌和成分方面的特性。薄膜的纹理非常清晰，并沿着乌兹结构的 c 轴优先取向。薄膜的粗糙度在纳米范围内较小，呈柱状微结构，晶粒大小为 100 纳米，镓极性（+c 平面定向）。RBS 和 NRA 分析表明，整个层深度的化学成分是均匀的，III/V 比率接近 1，氧含量非常低（低于检测限 ~1%），碳含量高达 11%。研究表明，等离子体功率的增加有助于将碳污染降低到 8%。这项研究为降低 III-V 薄膜生产成本的生长方法铺平了道路，通过在低压下进行 RP-CVD 操作可减少气体消耗。
{"title":"Direct growth of highly oriented GaN thin films on silicon by remote plasma CVD","authors":"Lise Watrin, François Silva, Cyril Jadaud, P. Bulkin, J. Vanel, Dominique Muller, Erik V Johnson, Karim Ouaras, P. Roca i Cabarrocas","doi":"10.1088/1361-6463/ad436c","DOIUrl":"https://doi.org/10.1088/1361-6463/ad436c","url":null,"abstract":"\u0000 We report on low-temperature (500°C) and low-pressure (0.3 mbar) direct growth of GaN thin films on silicon (100) substrates using Remote Plasma Chemical Vapor Deposition (RP-CVD). In the custom-designed reactor, an RF Inductively Coupled Plasma (ICP) is generated remotely from the substrate's area to facilitate the decomposition of group-V precursor, N2 with added H2, while group-III precursor Trimethylgallium (TMGa), is directly injected into the growth chamber mixed with H2 carrier gas. Growth parameters such as RF power, process pressure and gas flow rates have been optimized to achieve a film growth rate of about 0.6 µm/h. Several characterization techniques were used to investigate the plasma and the properties of the grown thin films in terms of their crystallinity, morphology, topography, and composition. The films are highly textured with a preferential orientation along the c-axis of the wurtzite structure. They present a small roughness in the nanometer range and a columnar microstructure with a grain size of one hundred nanometers, and a gallium polarity (+c plane oriented). RBS and NRA analysis show that the chemical composition is homogeneous through the depth of the layer, with a III/V ratio close to 1, a very low content of oxygen (below the detection limit ~1%) and a carbon content up to 11%. It was shown that that the increase of plasma power helps to reduce this carbon contamination down to 8%. This research paves the way for a growth method compatible with cost reduction of III-V thin film production achieved through reduced gas consumption facilitated by RP-CVD operation at low pressure.","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140656480","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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