Abstract We developed a time-resolved force microscopy technique by integrating the Atomic Force Microscope tuning fork-type cantilever with the delay time modulation method of optical pump-probe light. During the irradiation of the probe light, the instantaneous formation of dipoles induces a force between the probe and the sample, enabling the stable acquisition of a time-resolved force signal with a high signal-to-noise (SN) ratio. We successfully measured the dynamics of surface recombination and diffusion of photoexcited carriers in a bulk WSe2, which are challenging due to the effect of tunneling current in the time-resolved Scanning Tunneling Microscopy.
{"title":"Time-resolved force microscopy using delay-time modulation method","authors":"Hiroyuki Mogi, Rin Wakabayashi, Shoji YOSHIDA, Yusuke Arashida, Atsushi Taninaka, Katsuya Iwaya, Takeshi Miura, Osamu Takeuchi, Hidemi SHIGEKAWA","doi":"10.35848/1882-0786/ad0c04","DOIUrl":"https://doi.org/10.35848/1882-0786/ad0c04","url":null,"abstract":"Abstract We developed a time-resolved force microscopy technique by integrating the Atomic Force Microscope tuning fork-type cantilever with the delay time modulation method of optical pump-probe light. During the irradiation of the probe light, the instantaneous formation of dipoles induces a force between the probe and the sample, enabling the stable acquisition of a time-resolved force signal with a high signal-to-noise (SN) ratio. We successfully measured the dynamics of surface recombination and diffusion of photoexcited carriers in a bulk WSe2, which are challenging due to the effect of tunneling current in the time-resolved Scanning Tunneling Microscopy.","PeriodicalId":8093,"journal":{"name":"Applied Physics Express","volume":"58 18","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136281756","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 report on spin Hall magnetoresistance (SMR) in bilayers composed of Pt and magnetic insulator MgFe 2 O 4 (MFO) with spinel structure. The Pt thickness dependence of the SMR reveals that annealing of the MFO surface before depositing the Pt layer is crucial for a large SMR with better interface quality. We also found that oxygen pressure during the MFO growth hardly affects the SMR while it influences on magnetic property of the MFO film. Our findings provide important clues to further understand the spin transport at interfaces containing magnetic insulators, facilitating development of low power consumption devices.
{"title":"Effect of interface quality on spin Hall magnetoresistance in Pt/MgFe<sub>2</sub>O<sub>4</sub> bilayers","authors":"Masafumi Sugino, Kohei Ueda, Takanori Kida, Masayuki Hagiwara, Jobu MATSUNO","doi":"10.35848/1882-0786/ad0ba4","DOIUrl":"https://doi.org/10.35848/1882-0786/ad0ba4","url":null,"abstract":"Abstract We report on spin Hall magnetoresistance (SMR) in bilayers composed of Pt and magnetic insulator MgFe 2 O 4 (MFO) with spinel structure. The Pt thickness dependence of the SMR reveals that annealing of the MFO surface before depositing the Pt layer is crucial for a large SMR with better interface quality. We also found that oxygen pressure during the MFO growth hardly affects the SMR while it influences on magnetic property of the MFO film. Our findings provide important clues to further understand the spin transport at interfaces containing magnetic insulators, facilitating development of low power consumption devices.","PeriodicalId":8093,"journal":{"name":"Applied Physics Express","volume":"87 22","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135091441","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 Oxide vapor phase epitaxy (OVPE) has attracted much attention as a highly efficient method for synthesizing high-quality bulk GaN crystals, but the mechanical properties of the OVPE GaN have not been clarified. We measured the five independent elastic constants of the OVPE GaN by resonant ultrasound spectroscopy. The in-plane Young modulus E 1 and shear modulus C 66 of the OVPE GaN are smaller than those of the HVPE GaN by 1.8% and 1.3%, respectively. These reductions agree with predictions by the density functional theory calculations. We also calculated the Debye temperature, revealing that oxygen impurity decreases its magnitude.
{"title":"Elastic constants of GaN grown by oxide-vapor-phase-epitaxy method","authors":"Hiroki Fukuda, Akira NAGAKUBO, Shigeyoshi Usami, Masayuki Imanishi, Yusuke Mori, Hirotsugu OGI","doi":"10.35848/1882-0786/ad0ba2","DOIUrl":"https://doi.org/10.35848/1882-0786/ad0ba2","url":null,"abstract":"Abstract Oxide vapor phase epitaxy (OVPE) has attracted much attention as a highly efficient method for synthesizing high-quality bulk GaN crystals, but the mechanical properties of the OVPE GaN have not been clarified. We measured the five independent elastic constants of the OVPE GaN by resonant ultrasound spectroscopy. The in-plane Young modulus E 1 and shear modulus C 66 of the OVPE GaN are smaller than those of the HVPE GaN by 1.8% and 1.3%, respectively. These reductions agree with predictions by the density functional theory calculations. We also calculated the Debye temperature, revealing that oxygen impurity decreases its magnitude.","PeriodicalId":8093,"journal":{"name":"Applied Physics Express","volume":"88 19","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135091590","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 BiCh2-based layered compounds have been extensively studied as potential thermoelectric and unconventional superconducting materials. For both functionalities, in-plane chemical pressure effects improve their thermoelectric or superconducting properties. In this study, we investigate the effects of in-plane chemical pressure on atomic vibrations of Bi by analyzing lattice specific heat measured at T = 1.9–300 K with multiple Debye and Einstein models for thermoelectric LaOBi(S,Se)2 and superconducting LaO0.5F0.5Bi(S,Se)2. We reveal that in-plane chemical pressure enhances the oscillator number of the Einstein mode corresponding to large-amplitude Bi vibration along the c-axis in both the systems.
{"title":"Stabilization of Bi vibration along c-axis in BiS2-based layered compounds La(O,F)Bi(S,Se)2 by Se substitution","authors":"Fysol Ibna Abbas, Hiroto Arima, Md. Riad Kasem, Yuto Watanabe, Takumi Hasegawa, Chul-Ho Lee, Aichi Yamashita, Yoshikazu MIZUGUCHI","doi":"10.35848/1882-0786/ad0ba6","DOIUrl":"https://doi.org/10.35848/1882-0786/ad0ba6","url":null,"abstract":"Abstract BiCh2-based layered compounds have been extensively studied as potential thermoelectric and unconventional superconducting materials. For both functionalities, in-plane chemical pressure effects improve their thermoelectric or superconducting properties. In this study, we investigate the effects of in-plane chemical pressure on atomic vibrations of Bi by analyzing lattice specific heat measured at T = 1.9–300 K with multiple Debye and Einstein models for thermoelectric LaOBi(S,Se)2 and superconducting LaO0.5F0.5Bi(S,Se)2. We reveal that in-plane chemical pressure enhances the oscillator number of the Einstein mode corresponding to large-amplitude Bi vibration along the c-axis in both the systems.","PeriodicalId":8093,"journal":{"name":"Applied Physics Express","volume":"31 10","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135093125","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 : 2023-11-10DOI: 10.35848/1882-0786/ad0ba7
NARASIMHULU THOTI, Yiming Li
Abstract The purpose of this letter is to design and explore vertically stacked complementary tunneling field effect transistors (CTFETs) using complementary field effect transistor (CFET) technology for emerging technology nodes. As a prior work, the CTFET’s device level simulations are implemented and deliberated in strict compliance with the experimental demonstration requirements. This work comprises physical and DC characteristic examination by scaling the footprint (FP), which refers to the separation between p- to n-CTFET (D pn ). By utilizing the 50% reduction of FP, the work is extended to CTFET-6T SRAM demonstration and characterization with hold/read noise margin analysis.
{"title":"Design and exploration of vertically stacked complementary tunneling FETs","authors":"NARASIMHULU THOTI, Yiming Li","doi":"10.35848/1882-0786/ad0ba7","DOIUrl":"https://doi.org/10.35848/1882-0786/ad0ba7","url":null,"abstract":"Abstract The purpose of this letter is to design and explore vertically stacked complementary tunneling field effect transistors (CTFETs) using complementary field effect transistor (CFET) technology for emerging technology nodes. As a prior work, the CTFET’s device level simulations are implemented and deliberated in strict compliance with the experimental demonstration requirements. This work comprises physical and DC characteristic examination by scaling the footprint (FP), which refers to the separation between p- to n-CTFET (D pn ). By utilizing the 50% reduction of FP, the work is extended to CTFET-6T SRAM demonstration and characterization with hold/read noise margin analysis.","PeriodicalId":8093,"journal":{"name":"Applied Physics Express","volume":"86 25","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135092575","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 The origin of the ultralow thermal conductivity in amorphous Si thin films was investigated by comparing their phonon transport properties with those of single-crystal Si. The group velocity and thermal conductivity were measured at 300 K using nanoindentation and the 3ω method, respectively. The phonon mean free path (MFP) and phonon frequency were determined using the measured properties and models. The scattering in the disordered structure of amorphous Si thin films caused a significant decrease in the phonon MFP with increase in the phonon frequency, leading to ultralow thermal conductivity. However, the group velocity was unaffected by the disordered structure.
{"title":"Origin of ultralow thermal conductivity in amorphous Si thin films investigated using nanoindentation, 3ω method, and phonon transport analysis","authors":"Daiki Tanisawa, Tetsuya Takizawa, Asato Yamaguchi, Hiroshi Murotani, Masayuki Takashiri","doi":"10.35848/1882-0786/ad0ba3","DOIUrl":"https://doi.org/10.35848/1882-0786/ad0ba3","url":null,"abstract":"Abstract The origin of the ultralow thermal conductivity in amorphous Si thin films was investigated by comparing their phonon transport properties with those of single-crystal Si. The group velocity and thermal conductivity were measured at 300 K using nanoindentation and the 3ω method, respectively. The phonon mean free path (MFP) and phonon frequency were determined using the measured properties and models. The scattering in the disordered structure of amorphous Si thin films caused a significant decrease in the phonon MFP with increase in the phonon frequency, leading to ultralow thermal conductivity. However, the group velocity was unaffected by the disordered structure.","PeriodicalId":8093,"journal":{"name":"Applied Physics Express","volume":"24 9","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135136323","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 : 2023-11-10DOI: 10.35848/1882-0786/ad0ba8
Jinfeng Yang, Yongze Xu, Xiaonan Wang, Xu Zhang, Yang He, Huarui Sun
Abstract The thermal transport properties of Ga2O3 of different phases remain inadequately explored. We employ first-principles calculations and the phonon Boltzmann equation to systematically study the lattice thermal conductivity of β-, α- and κ-Ga2O3. Our results reveal that κ-Ga2O3 exhibits pronounced phonon anharmonicity due to its complex polyhedral configurations and weak bonding, resulting in significantly lower lattice thermal conductivity compared to β- and α-Ga2O3. This work provides critical knowledge of the fundamental phonon thermal transport properties of different-phase Ga2O3, as well as helpful guidance for the thermal design of Ga2O3-based high-power devices.
{"title":"Lattice thermal conductivity of β-, α- and κ- Ga<sub>2</sub>O<sub>3</sub>: a first-principles computational study","authors":"Jinfeng Yang, Yongze Xu, Xiaonan Wang, Xu Zhang, Yang He, Huarui Sun","doi":"10.35848/1882-0786/ad0ba8","DOIUrl":"https://doi.org/10.35848/1882-0786/ad0ba8","url":null,"abstract":"Abstract The thermal transport properties of Ga2O3 of different phases remain inadequately explored. We employ first-principles calculations and the phonon Boltzmann equation to systematically study the lattice thermal conductivity of β-, α- and κ-Ga2O3. Our results reveal that κ-Ga2O3 exhibits pronounced phonon anharmonicity due to its complex polyhedral configurations and weak bonding, resulting in significantly lower lattice thermal conductivity compared to β- and α-Ga2O3. This work provides critical knowledge of the fundamental phonon thermal transport properties of different-phase Ga2O3, as well as helpful guidance for the thermal design of Ga2O3-based high-power devices.","PeriodicalId":8093,"journal":{"name":"Applied Physics Express","volume":"86 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135092588","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 demonstrated a magnetic tunnel junction (MTJ) consisting of Fe/MgO-Si-MgO/Fe. Si layer was deposited at room temperature and at 700 ℃; when deposited at 700 ℃, Si diffused into the MgO layer. The MTJ with silicon deposited at 700 ℃ attained high MR ratios of up to 38.7 and 2.9% at t Si = 0.19 and 1.3 nm, respectively. Low-temperature measurements established that the temperature dependence of the MR ratio and resistance between MTJs with and without diffused silicon are significantly different. This behavior confirms that the Si-MgO channel acts as an impurity semiconductor in the MTJ.
摘要:我们展示了一种由Fe/MgO-Si-MgO/Fe组成的磁性隧道结(MTJ)。在室温和700℃下沉积Si层;在700℃沉积时，Si扩散到MgO层中。在700℃沉积硅的MTJ在t Si = 0.19和1.3 nm处的MR比分别高达38.7和2.9%。低温测量表明，含扩散硅和不含扩散硅的MTJs的磁流变比和电阻对温度的依赖性有显著差异。这种行为证实了Si-MgO通道在MTJ中作为杂质半导体。
{"title":"Magnetoresistance ratio in magnetic tunnel junction with silicon diffused MgO barrier","authors":"Tatsuki Watanabe, Minori Goto, Yuichiro Ando, Tsubasa Watakabe, Hikaru NOMURA, Yoshishige SUZUKI","doi":"10.35848/1882-0786/ad0ba1","DOIUrl":"https://doi.org/10.35848/1882-0786/ad0ba1","url":null,"abstract":"Abstract We demonstrated a magnetic tunnel junction (MTJ) consisting of Fe/MgO-Si-MgO/Fe. Si layer was deposited at room temperature and at 700 ℃; when deposited at 700 ℃, Si diffused into the MgO layer. The MTJ with silicon deposited at 700 ℃ attained high MR ratios of up to 38.7 and 2.9% at t Si = 0.19 and 1.3 nm, respectively. Low-temperature measurements established that the temperature dependence of the MR ratio and resistance between MTJs with and without diffused silicon are significantly different. This behavior confirms that the Si-MgO channel acts as an impurity semiconductor in the MTJ.","PeriodicalId":8093,"journal":{"name":"Applied Physics Express","volume":"76 26","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135092976","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 : 2023-11-10DOI: 10.35848/1882-0786/ad0ba5
Masakazu Kanechika, Takumi Hirata, Tomoya Tokozumi, Tetsu Kachi, Jun Suda
Abstract A novel post-deposition annealing technique employing ultra-high pressure was demonstrated. A 40 nm thick AlSiO gate insulator was deposited using ALD on n-type GaN layers. These PDAs were performed at 600 ºC in N2 under 400 MPa, with normal pressure. The annealing duration was varied within the range of 10-120 min. For the normal pressure annealing, the flat-band voltage exhibited a shift towards the positive bias direction as the annealing duration increased. Conversely, for the 400 MPa, the flat-band voltage approached the ideal curve. These results suggest that this annealing technique could be a method for improving the interfacial characteristics.
{"title":"Improvement of AlSiO/GaN interface by a novel post deposition annealing using ultra high pressure","authors":"Masakazu Kanechika, Takumi Hirata, Tomoya Tokozumi, Tetsu Kachi, Jun Suda","doi":"10.35848/1882-0786/ad0ba5","DOIUrl":"https://doi.org/10.35848/1882-0786/ad0ba5","url":null,"abstract":"Abstract A novel post-deposition annealing technique employing ultra-high pressure was demonstrated. A 40 nm thick AlSiO gate insulator was deposited using ALD on n-type GaN layers. These PDAs were performed at 600 ºC in N2 under 400 MPa, with normal pressure. The annealing duration was varied within the range of 10-120 min. For the normal pressure annealing, the flat-band voltage exhibited a shift towards the positive bias direction as the annealing duration increased. Conversely, for the 400 MPa, the flat-band voltage approached the ideal curve. These results suggest that this annealing technique could be a method for improving the interfacial characteristics.","PeriodicalId":8093,"journal":{"name":"Applied Physics Express","volume":"83 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135092087","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 Tunnel magnetocapacitance (TMC) ratios greater than 450% are observed at room temperature in epitaxial FeCo/MgAl 2 O 4 /FeCo(001) magnetic tunnel junctions (MTJs). A high TMC is observed at a low bias of 75 mV, which is suitable for low-power electronics. The fitting results between experimental data and calculation based on extended Debye–Fröhlich model reveal that the high TMC ratio is obtained owing to the high spin polarization of FeCo and the spin capacitance of the lattice-matched interface between FeCo and MgAl 2 O 4 . Based on this model, a TMC ratio could reach 1500% in MTJs with a spin polarization of 90%.
{"title":"Large magnetocapacitance of up to 456% at room temperature in FeCo/MgAl<sub>2</sub>O<sub>4</sub>/FeCo(001) magnetic tunnel junctions","authors":"Yuto Shibata, Kenta Sato, Hiroaki SUKEGAWA, Hideo Kaiju","doi":"10.35848/1882-0786/ad0b40","DOIUrl":"https://doi.org/10.35848/1882-0786/ad0b40","url":null,"abstract":"Abstract Tunnel magnetocapacitance (TMC) ratios greater than 450% are observed at room temperature in epitaxial FeCo/MgAl 2 O 4 /FeCo(001) magnetic tunnel junctions (MTJs). A high TMC is observed at a low bias of 75 mV, which is suitable for low-power electronics. The fitting results between experimental data and calculation based on extended Debye–Fröhlich model reveal that the high TMC ratio is obtained owing to the high spin polarization of FeCo and the spin capacitance of the lattice-matched interface between FeCo and MgAl 2 O 4 . Based on this model, a TMC ratio could reach 1500% in MTJs with a spin polarization of 90%.","PeriodicalId":8093,"journal":{"name":"Applied Physics Express","volume":" 10","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135192861","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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