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Longitudinal and transverse spatial beam profile measurement of relativistic electron bunch by electro-optic sampling Appl. Phys. Express (IF 3.086) Pub Date : 2021-01-16 Masato Ota, Koichi Kan, Soichiro Komada, Yasunobu Arikawa, Tomoki Shimizu, Valynn Katrine Mag-usara, Youichi Sakawa, Tatsunosuke Matsui and Makoto Nakajima
Electro-optic (EO) sampling is employed to measure the electric field profiles generated by a relativistic electron bunch along the propagation and in the radial directions. The longitudinal (temporal) profile is investigated by changing the time delay between the electron bunch and the pulsed probe laser, while the transverse (radial) profile is acquired by laterally shifting the path of the electron
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Possible impact of plasma oxidation on the structure of the C-terminal domain of SARS-CoV-2 spike protein: a computational study Appl. Phys. Express (IF 3.086) Pub Date : 2021-01-16 Pankaj Attri, Kazunori Koga and Masaharu Shiratani
The recent outbreak of a novel coronavirus (SARS-CoV-2) has caused substantial public health issues worldwide. Cold atmospheric plasma (CAP) has shown its potential application in sterilization. It would be interesting to check the possible effect of CAP on the structure of the C-terminal domain of SARS-CoV-2 (SARS-CoV-2-CTD) spike protein and the interaction SARS-CoV-2-CTD with human angiotensin-converting
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A drastic increase in critical thickness for strained SiGe by growth on mesa-patterned Ge-on-Si Appl. Phys. Express (IF 3.086) Pub Date : 2021-01-16 Youya Wagatsuma, Md. Mahfuz Alam, Kazuya Okada, Michihiro Yamada, Kohei Hamaya and Kentarou Sawano
We demonstrate that the critical thickness for Ge-rich strained SiGe layers can be drastically increased by a factor of more then two by means of growth on mesa-patterned Ge-on-Si. The Si 0.2 Ge 0.8 layer grown on sub-millimeter mesa Ge-on-Si is fully strained and free from ridge roughness, while the same Si 0.2 Ge 0.8 layers grown on unpatterned Ge-on-Si and a Ge substrate are partially strain-relaxed
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High thermal stability and low driven current achieved by vertical domain wall motion memory with artificial ferromagnet Appl. Phys. Express (IF 3.086) Pub Date : 2021-01-16 Yu Min Hung, Yoichi Shiota, Ryusuke Hisatomi, Takahiro Moriyama and Teruo Ono
To enhance thermal stability while keeping low driven current is difficult in traditional domain wall (DW) motion devices. The increasing of energy barrier for thermal stability inevitably results in the enhancement of driven current. We numerically investigate depinning field ( H depin ) and critical current density ( J c ) for DW motion as a function of uniaxial magnetic anisotropy ( K u ) in vertical
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Growth and characterization of metalorganic vapor-phase epitaxy-grown β -(Al x Ga 1− x ) 2 O 3 / β -Ga 2 O 3 heterostructure channels Appl. Phys. Express (IF 3.086) Pub Date : 2021-01-13 Praneeth Ranga, Arkka Bhattacharyya, Adrian Chmielewski, Saurav Roy, Rujun Sun, Michael A. Scarpulla, Nasim Alem and Sriram Krishnamoorthy
We report on the growth and characterization of metalorganic vapor-phase epitaxy-grown β -(Al x Ga 1− x ) 2 O 3 / β -Ga 2 O 3 modulation-doped heterostructures. Electron channel is realized in the heterostructure by utilizing a delta-doped β -(Al x Ga 1– x ) 2 O 3 barrier. The electron channel characteristics are studied using transfer length method, capacitance–voltage and Hall measurements. A Hall
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N-type conduction of sputter-deposited polycrystalline Al 0.78 Sc 0.22 N films by Si ion implantation Appl. Phys. Express (IF 3.086) Pub Date : 2021-01-13 Junji Kataoka, Sung-Lin Tsai, Takuya Hoshii, Hitoshi Wakabayashi, Kazuo Tsutsui and Kuniyuki Kakushima
N-type conduction of sputter-deposited polycrystalline Al 0.78 Sc 0.22 N films was verified by Si ion implantation followed by activation annealing. The activation of dopants was found above an annealing temperature of 800 °C. Under a dose of 2 × 10 15 cm −2 with an activation annealing at 900 °C, n-type conduction was obtained with Hall mobility and a carrier concentration of 8.6 cm 2 V −1 s −1 and
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Defect reduction and dopant activation of in situ phosphorus-doped silicon on a (111) silicon substrate using nanosecond laser annealing Appl. Phys. Express (IF 3.086) Pub Date : 2021-01-13 Hyunsu Shin, Juhee Lee, Eunjung Ko, Eunha Kim and Dae-Hong Ko
In situ phosphorus-doped silicon (ISPD) has been actively investigated as a source/drain material. However, defect formation during the epitaxial growth of ISPD layers in 3D structures deteriorate the device performance. In this study, we investigate the elimination of inherent defects in ISPD layers using nanosecond laser annealing (NLA). High-density twin- and stacking-fault defects in the ISPD layers
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Layer formation of 2,5-dihydroxybenzoic acid crystals via mist deposition for mass spectrometry imaging of biological samples Appl. Phys. Express (IF 3.086) Pub Date : 2021-01-13 Yuji Nakabayashi, Heisuke Sakai, Akio Miyazato, Chiko Shijimaya, Ryoichi Suzuki and Satoru Yamada
Dihydroxybenzoic acid (DHB) crystal layers were formed via mist deposition. Crystal layers exhibiting whiskers measuring a few hundred micrometers were formed at a nozzle temperature of 200 °C. DHB crystal layers exhibited strong absorbance in the ultra-violet wavelength regions, and Raman spectroscopy confirmed their vibrational property. The lipid component was analyzed by matrix-assisted laser
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Crystallite distribution analysis based on hydrogen content in thin-film nanocrystalline silicon solar cells by atom probe tomography Appl. Phys. Express (IF 3.086) Pub Date : 2021-01-12 Yasuo Shimizu, Hitoshi Sai, Takuya Matsui, Kenji Taki, Taiki Hashiguchi, Hirotaka Katayama, Mitsuhiro Matsumoto, Akira Terakawa, Koji Inoue and Yasuyoshi Nagai
The three-dimensional (3D) distribution of nanosized silicon (Si) crystallites within a hydrogenated nanocrystalline Si (nc-Si:H) material is examined by laser-assisted atom probe tomography (APT). The amorphous and crystalline phases in nc-Si:H are distinguished by obtaining the 3D density distribution of H atoms, because the former contains a high H density. The H content in the amorphous phase is
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A high sensitivity magnetometer via the combination of ultrahigh- Q fiber cavity and frequency-locking technology Appl. Phys. Express (IF 3.086) Pub Date : 2021-01-09 Guohui Xing, Enbo Xing, Yu Tao, Tong Xing, Jiamin Rong, Wenyao Liu, Jun Tang and Jun Liu
The optical cavity with high quality factor ( Q ) has been successfully employed to improve the sensitivity of magnetometer. However, complex system design and tedious data processing hinder the progress of application, since synchronized with other equipments and undergo additional post-processing. To overcome the limitation, we propose a single-loop frequency-locking (SLFL) optomagnetic (OM) signal
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A near-field vector sensing strategy for three-dimensional large-scale hybrid sound absorption Appl. Phys. Express (IF 3.086) Pub Date : 2021-01-09 Yang Liu, Kean Chen, Yanni Zhang and Jian Xu
A near-field vector sensing (VS) strategy is developed for three-dimensional (3D) large-scale hybrid sound absorption based on a lightweight structure. By simultaneously detecting sound pressures and normal particle velocities at discrete positions on the absorbing surface, the reflected sound power is minimized to obtain the optimal secondary excitation. For the one-dimensional case, low-frequency
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Dissolution kinetics of main-chain-scission-type resist in organic developers Appl. Phys. Express (IF 3.086) Pub Date : 2021-01-09 Ayako Nakajima, Keiko Matsuo and Takahiro Kozawa
Main-chain-scission-type resists have been widely used for the fabrication of nanodevices. A copolymer consisting of methyl α -chloroacrylate and α -methylstyrene, known as the ZEP series of ZEON, is a popular main-chain-scission-type positive-tone resist. In this study, the dissolution kinetics were investigated using the ZEP series to clarify the effects of the molecular weight distribution and developer
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Free-to-bound emission from interstitial carbon and oxygen defects (C i O i ) in electron-irradiated Si Appl. Phys. Express (IF 3.086) Pub Date : 2021-01-08 Michio Tajima, Shota Asahara, Yuta Satake and Atsushi Ogura
We determined the entire spectral shape of a broad band around 0.8 eV, previously termed the C08-band, which was observed commonly in Si by room-temperature photoluminescence after electron irradiation. The band has a peak at 0.77 ± 0.01 eV with long tails on both sides. We identified that the C08-band has the same origin as the C-line and occurs as a result of the recombination between a free electron
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Impact of gamma-ray irradiation on capacitance–voltage characteristics of Al 2 O 3 /GaN MOS diodes with and without post-metallization annealing Appl. Phys. Express (IF 3.086) Pub Date : 2021-01-08 Keito Aoshima, Masahiro Horita, Jun Suda and Tamotsu Hashizume
Atomic layer deposited Al 2 O 3 /GaN metal-oxide-semiconductor (MOS) diodes with and without post-metallization annealing (PMA) were irradiated with gamma-rays. Capacitance–voltage measurements were made before and after irradiation to investigate trap formation in Al 2 O 3 films and interface states between Al 2 O 3 and GaN. Negative flat-band voltage shifts were observed. The flat-band voltage shift
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Characterizing Rayleigh wave and longitudinal shear wave propagation for measurements of elastic moduli using optical coherence elastography Appl. Phys. Express (IF 3.086) Pub Date : 2021-01-08 Chongyang Wang, Jiang Zhu, Lianqing Zhu, Jianting Liu, Fan Fan, Qiang Yang and Fan Zhang
Optical coherence elastography based on the measurements of elastic wave speeds can quantify elastic moduli in the wave propagation directions and provide high-resolution elasticity maps for tissue. Here, we simultaneously visualized a longitudinal shear wave propagating along the depth and a Rayleigh wave propagating in the lateral direction, and analyzed the propagation characteristics of the elastic
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Enhanced two-photon excited fluorescence by ultrafast intensity fluctuations from an optical parametric generator Appl. Phys. Express (IF 3.086) Pub Date : 2021-01-08 Yujiro Eto
We evaluate the enhancement of two-photon excited fluorescence from fluorescent dye by ultrafast intensity fluctuations of light generated by a nanosecond optical parametric generator (OPG). By modifying the well-established techniques for measuring the second-order coherence on ultrashort timescale, we observed the enhancement of the fluorescence from Rhodamine B dye by a factor of two due to the
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wFLFM: enhancing the resolution of Fourier light-field microscopy using a hybrid wide-field image Appl. Phys. Express (IF 3.086) Pub Date : 2021-01-08 Wenhao Liu and Shu Jia
We introduce wFLFM, an approach that enhances the resolution of Fourier light-field microscopy (FLFM) through a hybrid wide-field image. The system exploits the intrinsic compatibility of image formation between the on-axis FLFM elemental image and the wide-field image, allowing for minimal instrumental and computational complexity. The numerical and experimental results of wFLFM present a two- to
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High-efficiency optical vortex generation with hybrid all-dielectric geometric-metasurface in visible frequency Appl. Phys. Express (IF 3.086) Pub Date : 2021-01-08 Xiaosai Wang, Bingyi Liu, Jiabao Yao, Jie Song and Yongyuan Jiang
We report a high-efficiency geometric-phase metasurface composed of hybrid all-dielectric nanofins, of which the conversion efficiency 93% is obtained in visible frequency. Such high efficiency originates from the stimulation of the anti-ferromagnetic resonance modes of polarization-dependent parity, i.e. even and odd number of anti-parallel magnetic dipoles would introduce π phase delay among two
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High-current recessed gate enhancement-mode ultrawide bandgap Al x Ga 1− x N channel MOSHFET with drain current 0.48 A mm −1 and threshold voltage +3.6 V Appl. Phys. Express (IF 3.086) Pub Date : 2021-01-08 Shahab Mollah, Kamal Hussain, Abdullah Mamun, Mikhail Gaevski, Grigory Simin, MVS Chandrashekhar and Asif Khan
We report a recessed-gate enhancement-mode Al 2 O 3 -ZrO 2 /Al 0.6 Ga 0.4 N/Al 0.4 Ga 0.6 N metal-oxide-semiconductor heterostructure field-effect transistor (MOSHFET) with drain current as high as 0.48 A mm −1 at a gate-source voltage of +12 V. This was enabled by a pseudomorphic HFET structure with graded back barrier for strain management and to screen the growth interface from the channel. The
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Tunable high-order harmonic and dual-wavelength mode-locking in Er-doped fiber laser based on Ti 3 C 2 T x -Mxene Appl. Phys. Express (IF 3.086) Pub Date : 2021-01-08 XiaoXin Yan, Man Jiang, Erkang Li, Xin Kang, Zhaoyu Ren, Duidui Li, Tianqi Wang and Baole Lu
We demonstrate an all fiber high-repetition-rate erbium-doped ultrashort laser based on the Ti 3 C 2 T x -Mxene saturable absorber (SA), and the 56th harmonic mode-locking with a repetition rate of 622.2 MHz, a central wavelength of 1590.7 nm, and a pulse duration of 1.31 ps is achieved. Meanwhile, dual-wavelength mode-locking pulses are also realized, with the central wavelengths of 1575.6, 1587.5 nm
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Dependency of high-speed write properties on external magnetic field in spin–orbit torque in-plane magnetoresistance devices Appl. Phys. Express (IF 3.086) Pub Date : 2021-01-08 Yohei Shiokawa, Eiji Komura, Yugo Ishitani, Atsushi Tsumita, Keita Suda, Kosuke Hamanaka, Tomohiro Taniguchi and Tomoyuki Sasaki
Spin–orbit torque (SOT) magnetoresistance (MR) devices have attracted attention for use in next-generation MR devices. The SOT devices are known to exhibit different write properties based on the relative angle between the magnetization direction of the free layer and the write-current direction. However, few studies that compare the write properties of each type have been reported. In this study,
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THz wave emission from the Cu 2 O/Cu interface under femtosecond laser irradiation Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-30 Yuen-Ting Rachel Chau, Hsin-hui Huang, Mai Thanh Nguyen, Koji Hatanaka and Tetsu Yonezawa
Cu or Cu/Au (80 nm thick Cu, 50 nm thick Au) sputtered on Si were kept at 25 °C for a week or annealed at a temperature from 80 to 300 °C, then tested for THz emission under femtosecond laser irradiation (35 fs-800 nm). THz radiation was detected from samples annealed from 80 to 170 °C, which had a Cu 2 O/Cu interface as the THz source. Cu/Au/Si annealed at 80 °C emitted the highest THz radiation because
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Over 80% power-added-efficiency GaN high-electron-mobility transistors on free-standing GaN substrates Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-30 Yusuke Kumazaki, Toshihiro Ohki, Junji Kotani, Shiro Ozaki, Yoshitaka Niida, Yuichi Minoura, Masato Nishimori, Naoya Okamoto, Masaru Sato, Norikazu Nakamura and Keiji Watanabe
This paper demonstrates highly efficient GaN high-electron-mobility transistors (HEMTs) on GaN substrates with reduced interface contamination. By applying a hydrofluoric acid-based pre-growth treatment to a GaN substrate, the Si impurity concentration at the interface between the GaN substrate and the epitaxial layer can successfully be reduced. RF performance was enhanced by pre-growth treatment
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A compact design for narrowband optical absorber based on surface plasmon polaritons Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-25 Xinguang Hu, Cheng Zeng, Jinsong Xia and Yunji Meng
A compact design for realizing narrowband optical absorbers at deep subwavelength is proposed, the physical regime of which is based on the excitation of quasi-surface plasmon polariton (quasi-SPP) mode at metal–substrate interface. Due to its small intrinsic loss balanced with the radiation loss, peak absorbance exceeding 99.9% with full width at half-maximum (FWHM) 2.6 nm is achieved at normal incidence
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Enhanced activation of Mg ion-implanted GaN at decreasing annealing temperature by prolonging duration Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-25 Takuya Nakashima, Emi Kano, Keita Kataoka, Shigeo Arai, Hideki Sakurai, Tetsuo Narita, Kacper Sierakowski, Michal Bockowski, Masahiro Nagao, Jun Suda, Tetsu Kachi and Nobuyuki Ikarashi
Defect time-evolution was investigated in Mg ion-implanted GaN after annealing at 1573 K for an unprecedentedly long duration. Transmission electron microscopy directly revealed that annealing for over 30 min reduced defects inhibiting Mg activation, just like annealing at 1753 K for a short duration. The cathodoluminescence intensity of donor–acceptor pair originating from Mg acceptors increased as
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Self-sweeping ytterbium-doped fiber laser based on a fiber saturable absorber Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-23 Zengrun Wen, Kaile Wang, Haowei Chen, Baole Lu and Jintao Bai
Generally speaking, the self-sweeping effect relies on the dynamical grating formed in active fiber. Here, the normal self-sweeping was generated in a ytterbium-doped fiber which serves as a fiber saturable absorber and is introduced to the laser cavity by a circulator in this experiment. The sweeping rate and the sweeping range alter as usual, both of which can be controlled by the pump power. Further
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In situ SEM observation and interface adhesion strength analysis of a serpentine interconnect on a flexible electronic composite film Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-23 Cheng Chen, Rui Chen, Wanghang Gu, Bing Liu and Hongwei Ji
The buckling deformation of a serpentine interconnect on a flexible electronic composite film is analyzed by a scanning electron microscope miniature tensile stage in situ observation workstation. The buckle formed at the junction of the interconnect pattern under a tensile load is observed. Combined with the buckle size and a theoretical model, the interface adhesion energy and shear stress are derived
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Measurement of escape time of concentrated DNA molecules in front of a nanogap Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-22 Naoki Azuma, Kenji Fukuzawa and Shintaro Itoh
In this study, we proposed a method to measure the escape time of DNA molecules trapped in front of a nanogap by concentrating DNA molecules in front of a nanogap and observing the escape process upon their entry. We measured the escape time for λ DNA molecules entering a 25 nm deep nanogap in the semi-dilute unentangled regime to verify the validity of our method. Our obtained escape time was the
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Cross-linking gelation of isomaltodextrin for the chromatographic separation of semiconducting carbon nanotubes Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-22 Yuki Matsunaga, Jun Hirotani, Yutaka Ohno and Haruka Omachi
The gel column chromatographic separation technique is one of the most rapid and reliable methods to prepare high-purity semiconducting single-wall carbon nanotubes (SWCNTs). However, the use of the expensive dextran-based gels limits the utility and scalability of this technique. Herein, we report the cross-linking gelation of a cost-efficient polysaccharide isomaltodextrin (IMD) for the high-purity
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An opto-thermal study of high brightness 280 nm emission AlGaN micropixel light-emitting diode arrays Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-18 Richard Floyd, Mikhail Gaevski, Md Didarul Alam, Samia Islam, Kamal Hussain, Abdullah Mamun, Shahab Mollah, Grigory Simin, MVS Chandrashekhar and Asif Khan
We present a study of the light output power and the thermal impedance of 281 nm emission AlGaN based micropixel LEDs. A modular interconnected micropixel array design is presented which enables dense packing with area and power scalability. We study5–15 μ m diameter stand-alone devices and parallel-connected micropixel arrays with5 μ m interpixel gaps. A standalone5 μ m pixel emits 291 W cm −2 at
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1:1 internal mode coupling strength in GaAs doubly-clamped MEMS beam resonators with linear and nonlinear oscillations Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-18 Ya Zhang, Yuri Yoshioka, Isao Morohashi and Xin Liu
We have investigated the 1:1 internal mode coupling strength in a GaAs doubly-clamped MEMS beam resonator by thermally tuning the frequencies of two neighbored resonant modes. The anti-crossing of the resonant frequencies indicates that the two modes couple with each other, and the mode coupling strength was estimated by the splitting of the anti-crossed frequencies of the two modes. When the oscillation
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Demonstration of ultra-small (<10 μ m) 632 nm red InGaN micro-LEDs with useful on-wafer external quantum efficiency (>0.2%) for mini-displays Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-17 Shubhra S. Pasayat, Chirag Gupta, Matthew S. Wong, Ryan Ley, Michael J. Gordon, Steven P. DenBaars, Shuji Nakamura, Stacia Keller and Umesh K. Mishra
Ultra-small red micro-LEDs(<10 μ m) with measurable output power have proved difficult to demonstrate. The smallest state-of-the-art red micro-LEDs (AlInGaP) to have exhibited a decent output power of ∼1.75 mW mm −2 are20 μm × 20 μ m in dimension. InGaN-based red micro-LED development has primarily been impeded due to the large lattice mismatch between the substrate and the quantum wells along with
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Non-equilibrium engineering of chemically grown SiO 2 /Si by UV nanosecond pulsed laser annealing from the viewpoint of bias temperature instability sources Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-16 Toshiyuki Tabata, Kenji Inoue, Yukifumi Yoshida and Hiroaki Takahashi
The impacts of high-temperature UV nanosecond pulsed laser annealing (LA) on a chemically grown SiO 2 /Si system are systematically investigated as a function of the number of irradiated pulses. A progressive transition is observed for both the tetrahedral SiO 4 network and the SiO 2 /Si interface, being assumed to play an essential role in controlling bulk SiO 2 traps and interface states. The presented
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Origin of recombination activity of non-coherent Σ3{111} grain boundaries with a positive deviation in the tilt angle in cast-grown silicon ingots Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-16 Yutaka Ohno, Takehiro Tamaoka, Hideto Yoshida, Yasuo Shimizu, Kentaro Kutsukake, Yasuyoshi Nagai and Noritaka Usami
Non-coherent Σ3{111} grain boundaries (GBs) with a positive deviation in the tilt angle ( θ 〈110〉 > 70.5°) exhibit a high recombination activity in high-performance multicrystalline silicon ingots. Most of the GB segments are composed of edge-type dislocations with the Burgers vector b of a /3〈111〉, unlike Lomer dislocations with b = a /2〈110〉 observed for negative deviations, arranged on coherent
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Laser displacement measurement using intensity modulation with a phase-modulated radio-frequency signal Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-16 Yosuke Tanaka, Kyosuke Yamaguchi, Kenta Yamamoto and Yoshiki Yamada
We demonstrate a laser-based displacement measurement using an intensity modulator as a simple and wide-band intensity correlator. The proposed method applies intensity modulation not only to the output probe beam but also to the reflected beam from a target, where the fundamental frequency of modulation signal is the same for both, but the phase of modulation signal for the reflected beam is also
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Aperture diameter dependences in GaN-based vertical-cavity surface-emitting lasers with nano-height cylindrical waveguide formed by BCl 3 dry etching Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-15 Ryosuke Iida, Yusuke Ueshima, Sho Iwayama, Tetsuya Takeuchi, Satoshi Kamiyama, Motoaki Iwaya, Isamu Akasaki, Masaru Kuramoto and Toshihiro Kamei
We demonstrated GaN-based vertical-cavity surface emitting lasers (VCSELs) with 5–30 μ m wide nano-height cylindrical waveguide formed by BCl 3 etching. A 5 nm-depth etching with BCl 3 showed the most efficient current blocking at the interface of the etched p ++ -GaN and an ITO electrode among the cases with BCl 3 , Ar, or O 2 , which could be due to not only etching damages but also diffused B atoms
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Inhomogeneous in-plane distribution of preferential glide planes of β dislocations in a metamorphic InGaAs solar cell Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-12 Akio Ogura, Shota Nogawa, Masahiro Kawano, Ryo Minematsu, Koshiro Kubo, Mitsuru Imaizumi and Hidetoshi Suzuki
By using synchrotron X-ray diffraction, we investigated the in-plane distribution of preferential glide planes in a metamorphic InGaAs solar cell with a relatively low open-circuit voltage ( V oc ) compared to other cells fabricated on the same wafer. The reciprocal-space maps revealed that the low- V oc cell contains several domains with different preferential glide planes of β dislocations. Since
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Relation between cut-off frequency and equivalent circuit of spoof surface plasmon polariton and its applications Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-11 Hongxin Zhao, Qipeng Wang, Leilei Liu and Xiaoxing Yin
This paper reveals a relation between the cut-off frequency and the simplified equivalent circuit of a spoof surface plasmon polariton (SSPP). An SSPP transmission line (TL) with low upper cut-off frequency is proposed based on the relation. In this SSPP-TL, a double-layer interdigital strip is constructed to increase the capacitance in the simplified equivalent circuit model, and in turn the cut-off
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LD-pumped 2.8 μ m Er:Lu 2 O 3 ceramic laser with 6.7 W output power and >30% slope efficiency Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-11 Weichao Yao, Hiyori Uehara, Shigeki Tokita, Hengjun Chen, Daisuke Konishi, Masanao Murakami and Ryo Yasuhara
We present a high-power, high-efficiency, laser-diode-pumped 2.8 μ m Er:Lu 2 O 3 ceramic laser generating record power at room temperature. Careful thermal management and pump-radius enlargement resulted in a continuous-wave output power of 6.7 W at 2845 nm, with a 30.2% slope efficiency. To our knowledge, this is the highest output power and slope efficiency ever achieved from a laser-diode-pumped
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Spinning indirectly coupled optical resonators Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-11 Haoye Qin, Yiheng Yin and Ming Ding
A spinning optical resonator is an excellent platform for realizing nonreciprocity. Here, we demonstrate the distinctive isolation features in spinning indirectly coupled resonators, where the nonreciprocal light propagation and probing mechanism via mechanical rotation have been achieved. Interplay with nanoparticles induces a tunable one- or two-way transmission through differential rotation, which
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Voltage control of spin–orbit torque in Pd/Co/Pd/HfO x Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-05 Takamasa Hirai, Yuki Hibino, Kento Hasegawa, Makoto Kohda, Tomohiro Koyama and Daichi Chiba
Voltage control of current-induced spin–orbit torque (SOT) in an in-plane-magnetized Pd/Co/Pd system with a low-temperature-deposited HfO x and a gate electrode on top is studied. An application of the gate electric field to the HfO x layer is to induce a non-volatile electrochemical effect from the Pd/HfO x interface. By means of low-frequency harmonic Hall measurements, the voltage modulation of
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Improvement of channel property of GaN vertical trench MOSFET by compensating nitrogen vacancies with nitrogen plasma treatment Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-05 Takashi Ishida, Kyung Pil Nam, Maciej Matys, Tsutomu Uesugi, Jun Suda and Tetsu Kachi
The electrical properties of vertical GaN trench MOSFETs without drift layers were evaluated to investigate the effect of nitrogen plasma treatment on the trench sidewalls. It is demonstrated that nitrogen plasma treatment improves the channel property of the vertical GaN trench MOSFET. The possible mechanism of this improvement is the supply of nitrogen atoms from nitrogen plasma treatment to the
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Characterization of the effect of ion irradiation on industrially produced GdBa 2 Cu 3 O 7− δ superconducting tapes using a slow positron beam Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-05 Atsushi Yabuuchi, Toshinori Ozaki, Hitoshi Sakane, Hiroyuki Okazaki, Hiroshi Koshikawa, Shunya Yamamoto and Tetsuya Yamaki
To investigate the effect of irradiation-induced defects on the superconducting characteristics of industrially produced superconductor—GdBa 2 Cu 3 O 7− δ (GdBCO)—coated conductors (CCs), we irradiated the GdBCO CCs with Au ions at 2 or 10 MeV and probed them using a slow positron beam. Vacancy clusters were detected in both unirradiated and irradiated GdBCO CCs. However, the effect of ion irradiation
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Large thermoelectric power factor in whisker crystals of solid solutions of the one-dimensional tellurides Ta 4 SiTe 4 and Nb 4 SiTe 4 Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-04 Yuma Yoshikawa, Taichi Wada, Yoshihiko Okamoto, Yasuhiro Abe and Koshi Takenaka
One-dimensional tellurides Ta 4 SiTe 4 and Nb 4 SiTe 4 were found to show high thermoelectric performance below room temperature. This study reported the synthesis and thermoelectric properties of Ta 4 SiTe 4 -Nb 4 SiTe 4 solid solutions and Mo- or Ti-doped (Ta 0.5 Nb 0.5 ) 4 SiTe 4 . Thermoelectric power of the solid solutions systematically increased with increasing Ta content, while their electrical
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Correlation between the internal quantum efficiency and photoluminescence lifetime of the near-band-edge emission in a ZnO single crystal grown by the hydrothermal method Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-04 Kazunobu Kojima and Shigefusa F. Chichibu
The internal quantum efficiency (IQE) and photoluminescence lifetime ##IMG## [http://ej.iop.org/images/1882-0786/13/12/121005/apexabcd73ieqn1.gif] {$\left({\tau }_{{\rm{PL}}}\right)$} of the near-band-edge emission in a ZnO single crystal grown by the hydrothermal method were measured by the omnidirectional photoluminescence and time-resolved photoluminescence spectroscopy, respectively. The IQE showed
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3D impurity profiles of doped/intrinsic amorphous-silicon layers composing textured silicon heterojunction solar cells detected by atom probe tomography Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-04 Yasuo Shimizu, Bin Han, Naoki Ebisawa, Yoshinari Ichihashi, Taiki Hashiguchi, Hirotaka Katayama, Mitsuhiro Matsumoto, Akira Terakawa, Koji Inoue and Yasuyoshi Nagai
Laser-assisted atom probe tomography was used to identify the impurity distribution in Si heterojunction (SHJ) solar cells composed of thin doped/intrinsic amorphous Si layers on the textured surface of a crystalline Si wafer. A site-specific lift-out technique involving a focused ion beam enabled the selection of a∼2 × 2 μ m 2 area on an arbitrary pyramidal surface. The distributions of B, P and C
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Uncooled bolometer for millimeter-wave detection using manganese-cobalt-nickel-oxide thin film Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-02 Tao Hu, Wanli Ma, Jing Wu, Zhibo Zhang, Wei Zhou, Niangjuan Yao, Qinxi Qiu and Zhiming Huang
A new type of high-performance and polarization-sensitive bolometer to detect millimeter waves is proposed, fabricated, and characterized using a Mn-Co-Ni-O film. The proposed bolometer successfully avoids the complicated micro-bridge structure and experimentally achieves sensitive polarization detection by planar dipole antennas. Besides, we introduce periodic metal grating structures on the active
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Optical amplification of single-photon polarization qubit using weak measurement Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-02 Ruitong Zhao, Jianjun Guo and Lianglun Cheng
Single-photon amplification can be used to overcome the photon loss in long-distance quantum communication. However, the trade-off of success probability and amplification gain should be further improved. We propose a single-photon polarization qubit amplification using weak measurement. The polarization qubit can be amplified by the pre- and post-selection of the single-photon meter state weakly coupling
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Detailed analysis of Ga-rich current pathways created in an n-Al 0.7 Ga 0.3 N layer grown on an AlN template with dense macrosteps Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-02 Yosuke Nagasawa, Akira Hirano, Masamichi Ippommatsu, Hideki Sako, Ai Hashimoto, Ryuichi Sugie, Yoshio Honda, Hiroshi Amano, Isamu Akasaki, Kazunobu Kojima and Shigefusa F. Chichibu
To clarify the behavior of the AlGaN in 20 nm wide Ga-rich current pathways in an n-AlGaN layer, which assists carrier localization in AlGaN-based light-emitting diodes, we performed a detailed analysis using an n-Al 0.7 Ga 0.3 N layer on AlN with dense macrosteps on a 1.0° miscut sapphire substrate. Energy-dispersive X-ray spectra, obtained using cross-sectional scanning transmission electron microscopy
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Interface-specific mode of protonation–deprotonation reactions underlies the cathodic modulation of fluorescence protein emission Appl. Phys. Express (IF 3.086) Pub Date : 2020-12-02 Trisha Diba Farha, Samyoung Kim, Kohsuke Hama, Mieko Imayasu, Yuichi Hiratsuka, Atsushi Miyawaki and Hidekazu Tsutsui
While fluorescence protein immobilized at the metal–solution interface has been known to exhibit voltage-dependent fluorescence, the underlying mechanism has remained unresolved. Here, we addressed the cathodic mechanism employing the characteristic properties of three different fluorescence proteins showing conventional pH-sensitivity, inverse pH-sensitivity, and green-to-red photo-convertibility
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High-quality AlInN/GaN distributed Bragg reflectors grown by metalorganic vapor phase epitaxy Appl. Phys. Express (IF 3.086) Pub Date : 2020-11-27 Takanobu Akagi, Yugo Kozuka, Kazuki Ikeyama, Sho Iwayama, Masaru Kuramoto, Tatsuma Saito, Takayuki Tanaka, Tetsuya Takeuchi, Satoshi Kamiyama, Motoaki Iwaya and Isamu Akasaki
We obtained a high-quality 40-pair AlInN/GaN distributed Bragg reflector with a high growth rate of the AlInN layers (500 nm h −1 ), showing almost no threading dislocations and a peak reflectivity of 99.9% at 413 nm, by using a 0.3 nm GaN cap layer grown on the AlInN layer at low growth temperature. We also found that the threading dislocations generated at the interfaces between the bottom AlInN
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Defect engineering in SiC technology for high-voltage power devices Appl. Phys. Express (IF 3.086) Pub Date : 2020-11-27 Tsunenobu Kimoto and Heiji Watanabe
Major features of silicon carbide (SiC) power devices include high blocking voltage, low on-state loss, and fast switching, compared with those of the Si counterparts. Through recent progress in the material and device technologies of SiC, production of 600–3300 V class SiC unipolar devices such as power metal-oxide-semiconductor field-effect transistors (MOSFETs) and Schottky barrier diodes has started
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Low-energy cross-sectional cathodoluminescence analysis of the depth distribution of point defects in Si-ion-implanted β -Ga 2 O 3 Appl. Phys. Express (IF 3.086) Pub Date : 2020-11-24 Ryuichi Sugie, Tomoyuki Uchida, Ai Hashimoto, Seishi Akahori, Koji Matsumura and Yoshiharu Tanii
Low-energy cross-sectional cathodoluminescence (CL) with a beam energy of 1 keV was applied to Si-ion-implanted β -Ga 2 O 3 (−201) wafers to investigate implantation damage and recovery. The semi-quantitative CL-intensity depth profiles were obtained by considering nonradiative recombination at the surface. We found that the CL intensity did not fully recover, even after annealing at 1273 K. Such insufficient
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Crystal growth and scintillation properties of tube shape-controlled Ce-doped Y 3 Al 5 O 12 single crystals grown by micro-pulling-down method Appl. Phys. Express (IF 3.086) Pub Date : 2020-11-24 Atsushi Kotaki, Masao Yoshino, Yuui Yokota, Takashi Hanada, Akihiro Yamaji, Satoshi Toyoda, Hiroki Sato, Yuji Ohashi, Shunsuke Kurosawa, Kei Kamada and Akira Yoshikawa
Tube shape-controlled Ce-doped Y 3 Al 5 O 12 (tube-Ce:YAG) single-crystal scintillators were directly grown from a melt via the micro-pulling-down method using a specially-designed iridium crucible. Back-scattering Laue images and X-ray diffraction measurements revealed the tube-Ce:YAG was a single crystal with the YAG phase. Ce distribution in the tangential direction of the tube-Ce:YAG specimen showed
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Room-temperature spin relaxation in a (110)-oriented GaAs/AlGaAs superlattice with tunnel-coupled quantum wells Appl. Phys. Express (IF 3.086) Pub Date : 2020-11-24 Yuzo Ohno, Satoshi Iba, Ryogo Okamoto, Yuma Obata, Kouki Obu, Jonathan Johan Pascual Domingez and Hidekazu Saito
We have investigated the electron spin relaxation time of a (110)-oriented GaAs/AlGaAs superlattice (SL) with tunnel-coupled quantum wells at room temperature. As the tunnel coupling between quantum wells increased, the spin relaxation time decreased. Even when the strength of tunnel coupling was as large as 25 meV, the spin relaxation time was 0.7 ns, about seven times longer than that of bulk GaAs
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Detection of tunneling events in physically defined silicon quantum dot using single-shot measurements improved by numerical treatments Appl. Phys. Express (IF 3.086) Pub Date : 2020-11-24 Raisei Mizokuchi, Masahiro Tadokoro and Tetsuo Kodera
We report the detection of a single tunneling event of electrons in a physically defined silicon quantum dot system. In the measurement, we observed single-shot tunneling events in a quantum dot using a charge sensor; however, the tunneling statistics are difficult to acquire because of their weak signals. Hence, two numerical treatments using a digital filter and a change point detection technique
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Synthesis and optical characterization of asymmetric multilayer metal–insulator nanocrescent in aqueous solutions Appl. Phys. Express (IF 3.086) Pub Date : 2020-11-21 Tien Thanh Pham, Dinh Dat Pham, Thi An Hang Nguyen, Minh Thong Vu, Lien Ha Thi Nghiem, Tien Van Nguyen, Daisuke Tanaka and Duc Cuong Nguyen
The metal–insulator–metal (MIM) nanostructures on polystyrene sphere (PS) were fabricated by the sputtering method. Asymmetric PS-MIM nanocrescent (AMNC) was separated and dispersed into the solution employing the sonication method. The absorption properties of AMNC colloidal solution were measured and calculated with the use of spectroscopy and discrete dipole approximation methods. The results indicated
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Optimization of barrier height in InGaN quantum wells for rapid interwell carrier transport and low nonradiative recombination Appl. Phys. Express (IF 3.086) Pub Date : 2020-11-21 Rinat Yapparov, Cheyenne Lynsky, Shuji Nakamura, James S. Speck and Saulius Marcinkevičius
Rapid interwell carrier transport is a key process for a uniform carrier distribution and reduced Auger recombination in multiple quantum well (MQW) light emitting devices. In this work, the interwell transport has been studied by time-resolved photoluminescence in In 0.12 Ga 0.88 N MQWs with In x Ga 1− x N ( x = 0 ÷ 0.06) and Al 0.065 Ga 0.935 N barriers. Only for the InGaN barriers the transport
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Ultrafast carrier dynamics in double perovskite Cs 2 AgBiBr 6 nanocrystals Appl. Phys. Express (IF 3.086) Pub Date : 2020-11-19 Quan Wang, Yongfeng Li, Wenyan Wang, Ning Sui, Xiaochun Chi, Lingyun Pan, Hanzhuang Zhang, Zhihui Kang, Qiang Zhou, Li Li and Yinghui Wang
The photon flux-dependent transient absorption spectroscopy is employed to investigate the carrier dynamics of Cs 2 AgBiBr 6 nanocrystals (NCs), exhibiting that the hot carrier cooling, the self-trapping process, the surface defect capture and the carrier recombination together participate in the carrier relaxation process after photoexcitation. The evolution of their lifetimes as a function of 〈N〉
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Observation of single phonon-mediated quantum transport in a silicon single-electron CMOS single-atom transistor by RMS noise analysis Appl. Phys. Express (IF 3.086) Pub Date : 2020-11-19 Stefano Bigoni, Marco L. V. Tagliaferri, Dario Tamascelli, Sebastiano Strangio, Roberto Bez, Paolo Organtini, Giorgio Ferrari and Enrico Prati
We explore phonon-mediated quantum transport through electronic noise characterization of a commercial CMOS transistor. The device behaves as a single electron transistor thanks to a single impurity atom in the channel. A low noise cryogenic CMOS transimpedance amplifier is exploited to perform low-frequency noise characterization down to the single electron, single donor and single phonon regime simultaneously
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