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Supplemental Materials
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All-Solid-State Electric-Double-Layer Transistor Based On Oxide Ion Migration in
Gd-Doped CeO2 on SrTiO3 Single Crystal
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Takashi Tsuchiya, Kazuya Terabe, and Masakazu Aono
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WPI Center for Materials Nanoarchitechtectonics, National Institute for Materials
Science,1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
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Supplement 1.
Vgs dependencies of two-dimensional carrier density and field-effect mobility
The Vgs dependencies of two-dimensional carrier density, n2D, and field-effect
mobility,  , are shown in Sup. 1. The n2D was calculated using the specific capacitance
obtained from ac impedance spectroscopy. The  was estimated by application of eq.
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(2) to the ids vs. Vgs characteristic in the first half of the voltage sweep.
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Supplement 2.
Temperature dependency of ids
Supplement 2 shows ids measured at various temperatures with Vgs of 3 V and
Vds of 0.5 V. It shows a metallic temperature dependency with a small decrease in ids,
namely 20 %, from room temperature to 473 K.
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Supplement 3.
Sample preparation
The STO-Pt cell containing layered thin films was fabricated on 0.5 wt% Nb
doped STO by PLD and radio-frequency (RF) sputtering (schematically shown in Sup.
3(a)). A 400-nm-thick GDC thin film is deposited on 0.5 wt% Nb-doped STO by PLD
under the same conditions as for the STO-based EDLT, followed by deposition of a
20-nm-thick top platinum electrode with dimensions of 1 × 1 mm.
The Pt-Pt cell containig layered thin films was fabricated on a Pt/Ti/SiO2/Si
substrate by PLD and RF sputtering (schematically shown in Sup. 3(b)). A
400-nm-thick GDC thin film was deposited on a Pt/Ti/SiO2/Si substrate, which had been
RF sputtered, by PLD under the same condition as for the STO-based EDLT, followed
by deposition of a 20-nm-thick top platinum electrode with dimensions of 1 × 1 mm.
In contrast to the (001) oriented GDC layer deposited on the STO, the one deposited on
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the Pt thin film exhibited a poly-crystalline structure with preferential growth parallel to
the (111) direction, as shown in Sups. 3 (c) and (d).
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Supplement 4.
AC impedance spectroscopy
AC impedance spectroscopy of both STO-Pt and Pt-Pt cells was conducted
with a typical frequency range of 1 MHz to 1 mHz and an ac bias voltage of 30 mV at
various temperature from 300 to 523 K in air. The impedance spectra of the STO-Pt and
Pt-Pt cells, measured at 473 and 430 K, and a bode plot of the Pt-Pt cell are shown in
Sups. 4 (a-c). In the analysis of the impedance spectra, the best fit to the experimental
data is made by the least square fitting method by assuming the equivalent circuit.
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Captions
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Sup. 1
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mobility (μ).
Vgs dependency of two-dimensional carrier density (n2D) and field-effect
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Sup. 2 Temperature dependency of ids measured at temperatures of 473, 400, 360, and
300 K with Vgs of 3 V and Vds of 0.5 V.
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Sup. 3 Schematic illustrations of (a) STO-Pt and (b) Pt-Pt two-terminal cells for ac
impedance spectroscopy. (c) HR-TEM image of GDC/Pt interface of Pt-Pt cell. (d)
X-ray diffraction pattern of Pt-Pt cell.
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Sup. 4 Cole-Cole plot of (a) STO-Pt and (b) Pt-Pt two terminal cells measured at 430
K in air. Insets show magnified view of high-frequency region of spectra. (c) Bode plot
of ac impedance spectroscopy results for Pt-Pt cell and diagram of equivalent circuit.
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Figures
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Sup. 1
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Sup. 2
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Sup. 3(a)
Sup. 3(b)
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Sup. 3(c)
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Sup. 3(d)
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Sup. 4(a)
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Sup. 4(b)
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Sup. 4(c)
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