著者

Horike Shohei Misaki Masahiro Koshiba Yasuko Morimoto Masahiro Saito Takeshi Ishida Kenji

出版者

Institute of Physics

雑誌

Appl. Phys. Express (ISSN:18820778)

巻号頁・発行日

vol.9, no.8, 2016-07-06

被引用文献数

9

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The tuning of the Seebeck coefficient of a single-walled carbon nanotube (SWCNT) film was achieved by using the dipole field of a ferroelectric polymer. The Seebeck coefficient was positive under an up-poling dipole field, but negative under a down-poling dipole field, whereas the control remained positive. This tunable behavior can be explained by selective carrier injection and accumulation, which was confirmed by the temperature dependence of electrical conductivity. Connecting p- and n-type SWCNT films tuned by dipole fields to create a π module resulted in a significant improvement in output voltage owing to the temperature difference between the two.

著者

Inoue Takaaki Mori Akimitsu Koshiba Yasuko Misaki Masahiro Ishida Kenji

出版者

Institute of Physics

雑誌

Appl. Phys. Express (ISSN:18820778)

巻号頁・発行日

vol.8, no.11, 2015-10-14

被引用文献数

3

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The ferroelectric properties of perpendicularly oriented, highly crystalline vinylidene fluoride (VDF) oligomer thin films were investigated by using a planar device configuration consisting of comblike Cr–Au electrodes with a 1 µm gap. In-plane polarization switching was induced by the rotation of the VDF oligomer. As the measurement temperature was increased from 295 to 380 K, the coercive field (E<inf>c</inf>) decreased drastically from 124 to 7.7 MV/m. Furthermore, the thermal stability of our device significantly improved compared with that of conventional sandwiched devices utilizing VDF oligomer films with a parallel orientation.

著者

Welch Adam Baranowski Lauryn Zawadzki Pawel Lany Stephan Wolden Colin Zakutayev Andriy

出版者

Institute of Physics

雑誌

Appl. Phys. Express (ISSN:18820778)

巻号頁・発行日

vol.8, no.8, 2015-07-06

被引用文献数

80

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Recent technical and commercial successes of existing thin-film solar cell technologies encourage the exploration of next-generation photovoltaic (PV) absorber materials. Of particular scientific interest are compounds that do not exhibit conventional tetrahedral semiconductor bonding, such as CuSbSe<inf>2</inf>. CuSbSe<inf>2</inf>has a 1.1 eV optical absorption onset, a 10⁵cm⁻¹absorption coefficient, and a hole concentration of 10¹⁷cm⁻³. Here, we demonstrate CuSbSe<inf>2</inf>PV prototypes with efficiencies >3%, prepared by a self-regulated sputtering process using a conventional substrate device architecture. Bulk recombination, device engineering issues, and a nonideal CuSbSe<inf>2</inf>/CdS band offset likely limit the promising initial result.

著者

Takahashi Hideyuki Okamoto Tsubasa Ohmichi Eiji Ohta Hitoshi

出版者

Institute of Physics

雑誌

Appl. Phys. Express (ISSN:18820778)

巻号頁・発行日

vol.9, no.12, 2016-10-27

被引用文献数

8

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We present a method of broadening the dynamic range of optical interferometric detection of cantilever displacement. The key idea of this method is the use of a wavelength-tunable laser source. The wavelength is subject to proportional-integral control, which is used to keep the cavity detuning constant. Under this control, the change in wavelength is proportional to the cantilever displacement. Using this technique, we can measure large displacements (>1 µm) without degrading the sensitivity. We apply this technique to high-frequency electron spin resonance spectroscopy and succeed in removing an irregular background signal that arises from the constantly varying sensitivity of the interferometer.

著者

Kojima Osamu Kita Takashi

出版者

Japan Society of Applied Physics

雑誌

Appl. Phys. Express (ISSN:18820778)

巻号頁・発行日

vol.9, no.6, 2016-05-09

被引用文献数

2

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In this study, we report the effects of the exciton line widths on the amplitude of quantum beat oscillations using a model with the Voigt function. Using the Voigt function, we find that the maximum amplitude appears at the central energy between two excitons. This result agrees with many previous experimental results. Our analysis helps in identifying the condition for strong quantum beat oscillation, which is important for device applications such as terahertz electromagnetic wave emitters and ultrafast switches.

著者

Morimoto Masahiro Koshiba Yasuko Misaki Masahiro Ishida Kenji

出版者

Institute of Physics

雑誌

Appl. Phys. Express (ISSN:18820778)

巻号頁・発行日

vol.8, no.10, 2015-10-01

被引用文献数

12

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We have investigated the temperature dependence of the piezoelectric coefficients and infrared sensor performance of spin-coated thin films of polyundecylurea (PUA11). The piezoelectric coefficients of the PUA11 films remained constant at temperatures above 180 °C and these films demonstrated thermal resistance superior to those of poly(vinylidene fluoride/trifluoroethylene) [P(VDF/TrFE)] films. The infrared sensor performance of the PUA11 films was measured after annealing at 125 °C for 500 h and was found to have retained 84% of its preannealing level. The thermal stability of the PUA11 films was higher than that of the P(VDF/TrFE) films; moreover, PUA11 is also expected to have superior electrothermal stability.

著者

Hayashi Shinji Nesterenko Dmitry Sekkat Zouheir

出版者

Institute of Physics

雑誌

Appl. Phys. Express (ISSN:18820778)

巻号頁・発行日

vol.8, no.2, 2015-01-06

被引用文献数

84

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A planar multilayer structure that allows coupling between surface plasmon polaritons and waveguide modes is proposed. Calculated reflectivity curves exhibit sharp resonances due to the Fano resonance and plasmon-induced transparency arising from the coupling. Electric field profiles obtained at the resonances demonstrate the hybrid nature of the modes excited. When the Fano resonance is used for sensing, the sensitivity with intensity modulation is enhanced by two orders of magnitude relative to that of conventional surface plasmon resonance sensors.