Dielectric loss in a C60 film observed by coupling with the external electromagnetic field of a surface acoustic wave

Sun, Yong; Yamasaki, Yuichi; Kirimoto, Kenta; Miyasato, Tatsuro; Wigmore, J. K.; Moriyama, Fuminori; Takase, Toru

doi:10.1063/1.1534917

Cited by 5 publications

(4 citation statements)

References 14 publications

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“…Details of the traveling-wave method have been reported in our previous works. 25,26) The SiC sample and SAW device were set in a cryostat chamber with a residual gas pressure of less than 2:0 Â 10 À5 Pa. The temperature of the sample was controlled using a temperature controller (Conductus LTC-20C) and a cryostat (Iwatani Industrial Gases D105) in the range of 20-300 K in steps of 1 K at a rate of 0.14 K min À1 .…”

Section: Methodsmentioning

confidence: 99%

Measurement of Ionization Energies of Nitrogen in 4H-SiC by Traveling-Wave Method

Takase

Sakaino

Sun

et al. 2013

Jpn. J. Appl. Phys.

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The impurity bands and corresponding ionization energies of nitrogen atoms in a 4H-SiC crystal with a concentration of 1×1019 cm-3 are measured by a nondestructive and noncontact traveling-wave method. When a SiC sample was placed near the surface of a surface acoustic wave device, its conductivity can be obtained by measuring the attenuation of the piezo-potential traveling-wave grazing along the surface of the sample. Temperature-dependent conductivities corresponding to a freeze-out process of free carriers excited from nitrogen atoms were observed, and the corresponding ionization energies of the nitrogen atoms were estimated by the Arrhenius plot method. The ionization energies in the impurity bands originating from splits of the doping atoms at cubic and hexagonal sites in the carbon sublattice are 72.89 and 47.89 meV, respectively, at room temperature. The ionization energies are in good agreement with the results reported in other theoretical and experimental studies. We also found that the skin depth of the traveling wave in the sample is below 1 mm and that the mobility of the carriers is strongly affected by both ionized dopants and charged surface defects in the depletion region near the surface of the sample. The effects of the sample and traveling wave such as the polarization effects of the crystal and the frequency effects of the traveling wave are discussed.

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Section: Methodsmentioning

confidence: 99%

Measurement of Ionization Energies of Nitrogen in 4H-SiC by Traveling-Wave Method

Takase

Sakaino

Sun

et al. 2013

Jpn. J. Appl. Phys.

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“…We have also studied the temperature dependences of C 60 and carbon nanotube films by using this method in our previous works. 18,19 Based on the above results, we found in this study that the traveling-wave energy loss in a semiconductor is proportional to Joule heat caused by current of the charge wave. Therefore, we can determine concentration and mobility of the carriers in semiconductor by measuring the travelingwave loss.…”

Section: Introductionmentioning

confidence: 93%

“…, at 270 K for 10 18 cm À3 and below 100 K for 10 16 cm À3 of the concentration. 21 In the high-frequency measurement of this study, the traveling-wave changes effectively the balance between lattice and ion scatterings as well as their temperature dependences.…”

Section: à3mentioning

confidence: 99%

Measurement of excited states of Sb impurity in Si by traveling–wave method

Sun

Takase

Sakaino

et al. 2012

Journal of Applied Physics

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The ground and excited states of Sb atom in Si, 1s (A 1 ), 1s (T 2 ), 1s (E), and 2p 0 , were measured by using a traveling-wave method. The Sb-doped Si crystal with donor concentration of 2 Â 10 15 cm À3 was placed the distance of 5 lm above a piezoelectric crystal in the fringe field of a surface acoustic wave. The free electrons excited from the bound states of the Sb atom are drifted by the traveling-wave, and thus lose their energy as the Joule heat through lattice and ion scattering processes. A strong temperature-dependent energy loss of the traveling-wave can be observed at temperatures below 200 K. The values of the bound states of the Sb atom can be characterized by using the Arrhenius plot for thermal activation process of the electrons in the bound states. The measurements were carried out at two frequencies of the traveling-wave, 50 MHz and 200 MHz. At the frequency of 50 MHz, the dielectric properties of the Si crystal are governed by dopant polarization but by electronic polarization at 200 MHz. We found that measurement accuracy of the bound states depends mainly on the electron mobility and the dielectric constant of the Si crystal, which are sensitive to the frequency and strength of the traveling-wave as well as electronic polarization properties of the Si crystal. V C 2012 American Institute of Physics. [http://dx

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“…[40][41][42] It has been used to characterize the drift mobility of semiconductors, 43 electromagnetic properties of two-dimensional electron system (2DES) on GaAs/Al x Ga 1-x As heterojunctions, 44,45 acoustoelectric currents in magnetic thin films, 46 superconducting properties of thin films, 47 and charge carrier mobility in organic thin films. 48 We have also reported several results obtained using this measurement method, for example, dielectric properties of C 60 and carbon nanotube films, 49,50 excitation states of antimony impurity in silicon, 51 ionization energies of nitrogen impurity in 4H-SiC crystal 52 in our previous works. By increasing coupling area of the sample with external electric field, we found that this method is very effective for characterizing ultra-thin sample.…”

Section: Introductionmentioning

confidence: 99%

Coupling behaviors of graphene/SiO2/Si structure with external electric field

2017

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A traveling electric field in surface acoustic wave was introduced into the graphene/SiO2/Si sample in the temperature range of 15 K to 300 K. The coupling behaviors between the sample and the electric field were analyzed using two parameters, the intensity attenuation and time delay of the traveling-wave. The attenuation originates from Joule heat of the moving carriers, and the delay of the traveling-wave was due to electrical resistances of the fixed charge and the moving carriers with low mobility in the sample. The attenuation of the external electric field was observed in both Si crystal and graphene films in the temperature range. A large attenuation around 190 K, which depends on the strength of external electric field, was confirmed for the Si crystal. But, no significant temperature and field dependences of the attenuation in the graphene films were detected. On the other hand, the delay of the traveling-wave due to ionic scattering at low temperature side was observed in the Si crystal, but cannot be detected in the films of the mono-, bi- and penta-layer graphene with high conductivities. Also, it was indicated in this study that skin depth of the graphene film was less than thickness of two graphene atomic layers in the temperature range.

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Dielectric loss in a C60 film observed by coupling with the external electromagnetic field of a surface acoustic wave

Cited by 5 publications

References 14 publications

Measurement of Ionization Energies of Nitrogen in 4H-SiC by Traveling-Wave Method

Measurement of Ionization Energies of Nitrogen in 4H-SiC by Traveling-Wave Method

Measurement of excited states of Sb impurity in Si by traveling–wave method

Coupling behaviors of graphene/SiO2/Si structure with external electric field

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