Pub Date : 2023-12-06DOI: 10.35848/1882-0786/ad1318
Yining Xuan, Rui Sun, Soyoung Baek, M. Sadgrove, Keiichi Edamatsu
This study explores the enhancement of emission from a single photon emitter in a quantum communication network by coupling the source with an optical nanofiber and leveraging gold nanoparticles for Purcell enhancement. Large Purcell enhancements of more than 50 times were recently reported experimentally, but understanding of important issues, including the maximum Purcell factor, and limits to quantum efficiency due to ohmic losses, is still lacking. Our findings reveal that the reported experimental results are reasonable, and confirm that such composite devices provide a promising route for high-efficiency single photon sources coupled to an optical fiber-based quantum communication network.
{"title":"Numerical investigation of plasmon-enhanced emission from a nanofiber coupled single photon emitter","authors":"Yining Xuan, Rui Sun, Soyoung Baek, M. Sadgrove, Keiichi Edamatsu","doi":"10.35848/1882-0786/ad1318","DOIUrl":"https://doi.org/10.35848/1882-0786/ad1318","url":null,"abstract":"\u0000 This study explores the enhancement of emission from a single photon emitter in a quantum communication network by coupling the source with an optical nanofiber and leveraging gold nanoparticles for Purcell enhancement. Large Purcell enhancements of more than 50 times were recently reported experimentally, but understanding of important issues, including the maximum Purcell factor, and limits to quantum efficiency due to ohmic losses, is still lacking. Our findings reveal that the reported experimental results are reasonable, and confirm that such composite devices provide a promising route for high-efficiency single photon sources coupled to an optical fiber-based quantum communication network.","PeriodicalId":8093,"journal":{"name":"Applied Physics Express","volume":"5 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138594737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-04DOI: 10.35848/1882-0786/ad120b
A. Kobayashi, Yoshio Honda, Takuya Maeda, Tomoya Okuda, K. Ueno, Hiroshi Fujioka
ScAlN has garnered substantial attention for its robust piezoelectric and ferroelectric properties, holding promise for diverse electronic device applications. However, the interplay between its structural attributes and physical properties remains poorly understood. Correlations between Sc composition, lattice constants, and film strains were revealed utilizing high-resolution X-ray diffraction, reciprocal space mapping, and machine learning analyses. Our machine-learning model predicted c-axis lattice constants of ScAlN grown on GaN under various conditions and suggested that sputtering permits coherent growth over a wide compositional range. These findings advance the understanding of ScAlN and provide valuable insights for the research and development of ScAlN-based device.
{"title":"Structural characterization of epitaxial ScAlN films grown on GaN by low-temperature sputtering","authors":"A. Kobayashi, Yoshio Honda, Takuya Maeda, Tomoya Okuda, K. Ueno, Hiroshi Fujioka","doi":"10.35848/1882-0786/ad120b","DOIUrl":"https://doi.org/10.35848/1882-0786/ad120b","url":null,"abstract":"\u0000 ScAlN has garnered substantial attention for its robust piezoelectric and ferroelectric properties, holding promise for diverse electronic device applications. However, the interplay between its structural attributes and physical properties remains poorly understood. Correlations between Sc composition, lattice constants, and film strains were revealed utilizing high-resolution X-ray diffraction, reciprocal space mapping, and machine learning analyses. Our machine-learning model predicted c-axis lattice constants of ScAlN grown on GaN under various conditions and suggested that sputtering permits coherent growth over a wide compositional range. These findings advance the understanding of ScAlN and provide valuable insights for the research and development of ScAlN-based device.","PeriodicalId":8093,"journal":{"name":"Applied Physics Express","volume":"22 12","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138601752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-04DOI: 10.35848/1882-0786/ad120a
Takuma Kobayashi, Kazuki Tomigahara, M. Nozaki, T. Shimura, Heiji Watanabe
Understanding the traps in metal-oxide-semiconductor (MOS) structures is crucial to fabricate MOS transistors with high performance and reliability. In this study, we evaluated the hole traps in SiO2/GaN MOS structures through photo-assisted capacitance-voltage measurements. Below- and above-gap light was used to distinguish between the contributions of fast interface and slow oxide hole traps. While annealing in oxygen is effective in reducing the oxide hole traps, a high density of hole traps exceeding 1012 cm-2eV-1 remains at the interface. Although these traps are donor-type and thus hidden in n-type MOS structures, they could impair the switching performance of GaN MOS transistors.
{"title":"Separate evaluation of interface and oxide hole traps in SiO2/GaN MOS structures with below- and above-gap light excitation","authors":"Takuma Kobayashi, Kazuki Tomigahara, M. Nozaki, T. Shimura, Heiji Watanabe","doi":"10.35848/1882-0786/ad120a","DOIUrl":"https://doi.org/10.35848/1882-0786/ad120a","url":null,"abstract":"\u0000 Understanding the traps in metal-oxide-semiconductor (MOS) structures is crucial to fabricate MOS transistors with high performance and reliability. In this study, we evaluated the hole traps in SiO2/GaN MOS structures through photo-assisted capacitance-voltage measurements. Below- and above-gap light was used to distinguish between the contributions of fast interface and slow oxide hole traps. While annealing in oxygen is effective in reducing the oxide hole traps, a high density of hole traps exceeding 1012 cm-2eV-1 remains at the interface. Although these traps are donor-type and thus hidden in n-type MOS structures, they could impair the switching performance of GaN MOS transistors.","PeriodicalId":8093,"journal":{"name":"Applied Physics Express","volume":"16 11","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138602954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-02DOI: 10.35848/1882-0786/ad119b
Nathan C. Palmquist, Jared A. Kearns, Stephenn M Gee, Arturo Juan, Srinivas Gandrothula, Michael Lam, S. Denbaars, S. Nakamura
We report long cavity (65lambda) GaN-based vertical-cavity surface-emitting lasers (VCSELs) with a topside dielectric concave mirror, an ion implanted current aperture, and a bottomside nanoporous GaN distributed Bragg reflector. Under pulsed operation, a VCSEL with a 10µm aperture and a curved mirror with a radius of curvature (ROC) of 120µm had a threshold current density of 14kA/cm2, and a maximum output power of 370µW for a lasing mode at 404.5nm. The longitudinal performance has a side-mode suppression ratio of 30dB up to a current density of approximately 40kA/cm2. Multiple transverse mode profiles are observed across several devices.
{"title":"Demonstration of III-nitride vertical-cavity surface-emitting lasers with a topside dielectric curved mirror","authors":"Nathan C. Palmquist, Jared A. Kearns, Stephenn M Gee, Arturo Juan, Srinivas Gandrothula, Michael Lam, S. Denbaars, S. Nakamura","doi":"10.35848/1882-0786/ad119b","DOIUrl":"https://doi.org/10.35848/1882-0786/ad119b","url":null,"abstract":"\u0000 We report long cavity (65lambda) GaN-based vertical-cavity surface-emitting lasers (VCSELs) with a topside dielectric concave mirror, an ion implanted current aperture, and a bottomside nanoporous GaN distributed Bragg reflector. Under pulsed operation, a VCSEL with a 10µm aperture and a curved mirror with a radius of curvature (ROC) of 120µm had a threshold current density of 14kA/cm2, and a maximum output power of 370µW for a lasing mode at 404.5nm. The longitudinal performance has a side-mode suppression ratio of 30dB up to a current density of approximately 40kA/cm2. Multiple transverse mode profiles are observed across several devices.","PeriodicalId":8093,"journal":{"name":"Applied Physics Express","volume":"123 32","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138606912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-02DOI: 10.35848/1882-0786/ad119a
Shotaro Matsumura, Iori Ogasahara, Masafumi Miyake, T. Osaka, D. Toh, J. Yamada, M. Yabashi, K. Yamauchi, Y. Sano
We developed a new etching technique using plasma generated at high pressure up to 9 atm. Operating at 9-atm pressure with a 30-μm-diameter wire electrode, we demonstrate the generation of well-ordered plasma at a narrow gap of ~10 μm between the electrode and workpiece, and realize a high spatial resolution in processing of <40 μm during processing. This technique should allow for the processing of the high-precision X-ray crystal optical devices with compact and complex structures, such as a micro channel-cut crystal monochromator with an extremely narrow (sub-100 μm width) groove for realization of Fourier-transform-limited X-ray lasers with high intensity.
{"title":"High-pressure plasma etching up to 9 atm toward uniform processing inside narrow grooves of high-precision X-ray crystal optics","authors":"Shotaro Matsumura, Iori Ogasahara, Masafumi Miyake, T. Osaka, D. Toh, J. Yamada, M. Yabashi, K. Yamauchi, Y. Sano","doi":"10.35848/1882-0786/ad119a","DOIUrl":"https://doi.org/10.35848/1882-0786/ad119a","url":null,"abstract":"\u0000 We developed a new etching technique using plasma generated at high pressure up to 9 atm. Operating at 9-atm pressure with a 30-μm-diameter wire electrode, we demonstrate the generation of well-ordered plasma at a narrow gap of ~10 μm between the electrode and workpiece, and realize a high spatial resolution in processing of <40 μm during processing. This technique should allow for the processing of the high-precision X-ray crystal optical devices with compact and complex structures, such as a micro channel-cut crystal monochromator with an extremely narrow (sub-100 μm width) groove for realization of Fourier-transform-limited X-ray lasers with high intensity.","PeriodicalId":8093,"journal":{"name":"Applied Physics Express","volume":"125 18","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138606968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The effect of tetramethylammonium hydroxide (TMAH) treatment prior to gate dielectric deposition on the performance of recessed-gate AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs) was investigated. By using of TMAH wet etching, low roughness etched surface of 0.173 nm was obtained. The capacitance-voltage characteristics of MIS heterostructures showed the interface states reduced by one order of magnitude. When temperature was increased to 473 K, the treated MIS-HEMTs delivered small threshold voltage shift (ΔVTH) of ~-0.53 V. From the dynamic measurement, ΔVTH obtained without treatment was observed more severely (~-1 V) when compared to the treated one (~-0.01 V).
{"title":"Effective suppression of interface states in recessed-gate MIS-HEMTs by TMAH wet etching","authors":"Yu Li, Guohao Yu, Heng Wang, Jiaan Zhou, Zheming Wang, Runxian Xing, Shaoqian Lu, An Yang, Bingliang Zhang, Yong Cai, Zhongming Zeng, Baoshun Zhang","doi":"10.35848/1882-0786/ad1199","DOIUrl":"https://doi.org/10.35848/1882-0786/ad1199","url":null,"abstract":"\u0000 The effect of tetramethylammonium hydroxide (TMAH) treatment prior to gate dielectric deposition on the performance of recessed-gate AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs) was investigated. By using of TMAH wet etching, low roughness etched surface of 0.173 nm was obtained. The capacitance-voltage characteristics of MIS heterostructures showed the interface states reduced by one order of magnitude. When temperature was increased to 473 K, the treated MIS-HEMTs delivered small threshold voltage shift (ΔVTH) of ~-0.53 V. From the dynamic measurement, ΔVTH obtained without treatment was observed more severely (~-1 V) when compared to the treated one (~-0.01 V).","PeriodicalId":8093,"journal":{"name":"Applied Physics Express","volume":"117 17","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138607410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-01DOI: 10.35848/1882-0786/ad0db8
Zhijian He, Daifeng Zou, Qiong Yang, Tianpeng Duan, Yingjun Tan, Chihou Lei, Shuhong Xie and Yunya Liu
Fe3Ga/HfO2/Fe3Ga heterojunction possesses reasonable lattice mismatch and good ferroelectric at the nanoscale. However, its magnetoelectric coupling is unexplored. Based on the first-principles calculations, we demonstrate that the magnetoelectric coupling in Fe3Ga/HfO2/Fe3Ga heterojunction is induced by polarization, which is different from the common strain-mediated magnetoelectric effect. The polarization-induced magnetoelectric effect of heterojunction is explained by the analyses of orbital-resolved density of states and spin densities, finding that the interfaces between Fe3Ga and HfO2 play an important role in magnetoelectric coupling, offering an alternative pathway for generating magnetoelectric coupling at room temperature.
{"title":"Polarization-induced magnetoelectric effect in Fe3Ga/HfO2/Fe3Ga heterojunction","authors":"Zhijian He, Daifeng Zou, Qiong Yang, Tianpeng Duan, Yingjun Tan, Chihou Lei, Shuhong Xie and Yunya Liu","doi":"10.35848/1882-0786/ad0db8","DOIUrl":"https://doi.org/10.35848/1882-0786/ad0db8","url":null,"abstract":"Fe3Ga/HfO2/Fe3Ga heterojunction possesses reasonable lattice mismatch and good ferroelectric at the nanoscale. However, its magnetoelectric coupling is unexplored. Based on the first-principles calculations, we demonstrate that the magnetoelectric coupling in Fe3Ga/HfO2/Fe3Ga heterojunction is induced by polarization, which is different from the common strain-mediated magnetoelectric effect. The polarization-induced magnetoelectric effect of heterojunction is explained by the analyses of orbital-resolved density of states and spin densities, finding that the interfaces between Fe3Ga and HfO2 play an important role in magnetoelectric coupling, offering an alternative pathway for generating magnetoelectric coupling at room temperature.","PeriodicalId":8093,"journal":{"name":"Applied Physics Express","volume":"43 3","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138509371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-27DOI: 10.35848/1882-0786/ad1003
Tingting Yang, Yao Cai, Chao Gao, Qinwen Xu, Yang Zou, Yan Liu, Wenjuan Liu, Cheng Lei, Chengliang Sun
This paper introduces a piezoelectric ring resonator, comprising a Mo-ScAlN-Mo sandwich structure and shaped into a ring with a hollow center. The vibrational modes of the resonator are elucidated through simulation and theoretical analysis, and the impact of diverse geometric parameters on the resonant frequency is explored. A high frequency resonator with a resonance frequency of 4.168 GHz has been fabricated. The electrical parameters of this resonator are extracted by fitting the Modified Butterworth-Van Dyke (MBVD) equivalent circuit model and the measured results. This work establishes a theoretical foundation for designing resonators with adjustable frequencies on a single wafer.
{"title":"Analysis and measurement of high frequency piezoelectric ring resonator","authors":"Tingting Yang, Yao Cai, Chao Gao, Qinwen Xu, Yang Zou, Yan Liu, Wenjuan Liu, Cheng Lei, Chengliang Sun","doi":"10.35848/1882-0786/ad1003","DOIUrl":"https://doi.org/10.35848/1882-0786/ad1003","url":null,"abstract":"This paper introduces a piezoelectric ring resonator, comprising a Mo-ScAlN-Mo sandwich structure and shaped into a ring with a hollow center. The vibrational modes of the resonator are elucidated through simulation and theoretical analysis, and the impact of diverse geometric parameters on the resonant frequency is explored. A high frequency resonator with a resonance frequency of 4.168 GHz has been fabricated. The electrical parameters of this resonator are extracted by fitting the Modified Butterworth-Van Dyke (MBVD) equivalent circuit model and the measured results. This work establishes a theoretical foundation for designing resonators with adjustable frequencies on a single wafer.","PeriodicalId":8093,"journal":{"name":"Applied Physics Express","volume":"50 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139234794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract We have designed a directly-displayed refractive index detection chip based on an ultra-thin rotating metal nanopillars. When environments fluctuate, it can focus the detection signal on different directions as designed. This refractive index compass can be easily attached to conventional portable devices due to its compact structure, and has a wide adjustable working range. By utilizing multiple sets of phase information contained in a single metasurface, the environmental refractive index on surface or solution concentration can be accurately determined by observing the position and color of the focal point under dual wavelength common incidence.
{"title":"Concentration monitoring through a refractive index compass based on metasurface","authors":"Wenjie Sun, Yikai Chen, Xilong Liu, Junfeng Li, Zekai Wang, Shijun Zhu, Zhonghua Shen","doi":"10.35848/1882-0786/ad0c79","DOIUrl":"https://doi.org/10.35848/1882-0786/ad0c79","url":null,"abstract":"Abstract We have designed a directly-displayed refractive index detection chip based on an ultra-thin rotating metal nanopillars. When environments fluctuate, it can focus the detection signal on different directions as designed. This refractive index compass can be easily attached to conventional portable devices due to its compact structure, and has a wide adjustable working range. By utilizing multiple sets of phase information contained in a single metasurface, the environmental refractive index on surface or solution concentration can be accurately determined by observing the position and color of the focal point under dual wavelength common incidence.","PeriodicalId":8093,"journal":{"name":"Applied Physics Express","volume":"4 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134954400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-13DOI: 10.35848/1882-0786/ad0c05
Rui Tian, Hao Zhou, Jie Hu
Abstract How to modulate the acoustic waves at small scales has been an area of intense investigation. In this paper, an artificial ultrathin structure with a series of zigzag-shaped grooves located in the center and bilateral symmetry is designed to realize ultra-strong directional collimated acoustic beams. The simulations agree well with the theoretical analysis and show that the acoustic collimated structure has high directivity at the resonant frequency with the beam length exceeding 40 wavelengths. The structure has deep subwavelength scales and simple design, which are expected to have applications in fields like directional acoustic radiation, medical ultrasound detection, et
{"title":"Acoustic collimation based on an ultra-thin metasurface","authors":"Rui Tian, Hao Zhou, Jie Hu","doi":"10.35848/1882-0786/ad0c05","DOIUrl":"https://doi.org/10.35848/1882-0786/ad0c05","url":null,"abstract":"Abstract How to modulate the acoustic waves at small scales has been an area of intense investigation. In this paper, an artificial ultrathin structure with a series of zigzag-shaped grooves located in the center and bilateral symmetry is designed to realize ultra-strong directional collimated acoustic beams. The simulations agree well with the theoretical analysis and show that the acoustic collimated structure has high directivity at the resonant frequency with the beam length exceeding 40 wavelengths. The structure has deep subwavelength scales and simple design, which are expected to have applications in fields like directional acoustic radiation, medical ultrasound detection, et","PeriodicalId":8093,"journal":{"name":"Applied Physics Express","volume":"53 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136281916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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