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^{1,a)}, Huilong Xu

^{1}, Hua Zhong

^{1}and Lian-Mao Peng

^{1,a)}

### Abstract

Top gated graphenefield-effect transistors were fabricated using yttrium oxide film as high-*κ* gate dielectric, and the gate voltage dependent drain current and gate capacitance characteristics were both measured on one graphene device. Based on the two kinds of data sets, we developed a method to extract the carrier mobility of graphenefield-effect transistors, along with some other parameters, such as series resistance and residual carrier density. Prior to previous method, this method could well fit the transfer curve of graphenefield-effect transistor with high gate oxide capacitance since its carrier concentration is directly obtained from the experimental data rather than from analytic equation.

This work was supported by the Ministry of Science and Technology of China (Grant Nos. 2011CB933001 and 2011CB933002), and National Science Foundation of China (Grant No. 61071013).

### Key Topics

- Capacitance
- 30.0
- Carrier mobility
- 27.0
- Graphene
- 26.0
- Carrier density
- 17.0
- Dirac equation
- 10.0

##### H01L29/00

## Figures

(a) Side-view schematic of a G-FET, and (b) its SEM image. The scale bar is 2 *μ*m. The graphene channel is in the rectangle frame, while the Y_{2}O_{3} dielectric layer is in the square. The gate width and length are 4.5 *μ*m and 7 *μ*m, respectively, and the separation between source/drain electrodes to the top gate electrode is 1.2 *μ*m. (c) Transfer curves of theG-FET under different back-gate voltage which is 60 V, 0 V, and −60 V, respectively, from left to right. (d) The gate voltage dependent gate capacitance curve, in which the Dirac voltage is drifted to zero manually.

(a) Side-view schematic of a G-FET, and (b) its SEM image. The scale bar is 2 *μ*m. The graphene channel is in the rectangle frame, while the Y_{2}O_{3} dielectric layer is in the square. The gate width and length are 4.5 *μ*m and 7 *μ*m, respectively, and the separation between source/drain electrodes to the top gate electrode is 1.2 *μ*m. (c) Transfer curves of theG-FET under different back-gate voltage which is 60 V, 0 V, and −60 V, respectively, from left to right. (d) The gate voltage dependent gate capacitance curve, in which the Dirac voltage is drifted to zero manually.

The detailed process for retrieving carrier mobility and other parameters from - and - data of G-FET at back gate = 0 V. The Dirac voltage is translated to zero intentionally for simple. (a) dependent 1/n calculated from Fig. 1(d). (b) dependent total channel resistance calculated from Fig. 1(c). (c) vs 1/n at n-branch of G-FET. The retrieved parameters are = 8.2 × 10^{11} cm^{−2}, slope = 7.31 × 10^{15} Ω cm^{2}, = 3.56 kΩ. (d) vs 1/n at p-branch of G-FET. The retrieved parameters are = 8.0 × 10^{11} cm^{−2}, slope = 7.21 × 10^{15} Ω cm^{2}, = 3.50 kΩ. (e) dependent carrier density n calculated from the retrieved parameters. (f) The experimental - relation along with the fitted result. (g) - curve fitted through conventional method developed in Ref. 11 with = 1 × 10^{6} m/s. (h) - curve fitted with = 1.2 × 10^{6} m/s.

The detailed process for retrieving carrier mobility and other parameters from - and - data of G-FET at back gate = 0 V. The Dirac voltage is translated to zero intentionally for simple. (a) dependent 1/n calculated from Fig. 1(d). (b) dependent total channel resistance calculated from Fig. 1(c). (c) vs 1/n at n-branch of G-FET. The retrieved parameters are = 8.2 × 10^{11} cm^{−2}, slope = 7.31 × 10^{15} Ω cm^{2}, = 3.56 kΩ. (d) vs 1/n at p-branch of G-FET. The retrieved parameters are = 8.0 × 10^{11} cm^{−2}, slope = 7.21 × 10^{15} Ω cm^{2}, = 3.50 kΩ. (e) dependent carrier density n calculated from the retrieved parameters. (f) The experimental - relation along with the fitted result. (g) - curve fitted through conventional method developed in Ref. 11 with = 1 × 10^{6} m/s. (h) - curve fitted with = 1.2 × 10^{6} m/s.

The retrieved carrier mobility and other parameters from - and - data of G-FET at back gate = −60 V and 60 V. (a) dependent total channel resistance calculated from Fig. 1(c) under = −60 V. (b) vs 1/n at n-branch of the G-FET under = −60 V. The retrieved parameters are = 9.33 × 10^{11} cm^{−2}, slope = 9.63 × 10^{15} Ω cm^{2}, = 1.83 kΩ. (c) dependent total channel resistance calculated from Fig. 1(c) under = 60 V. (d) vs 1/n at p-branch of G-FET under = −60 V. The retrieved parameters are = 1.04 × 10^{12} cm^{−2}, slope = 8.84 × 10^{15} Ω cm^{2}, = 2.36 kΩ.

The retrieved carrier mobility and other parameters from - and - data of G-FET at back gate = −60 V and 60 V. (a) dependent total channel resistance calculated from Fig. 1(c) under = −60 V. (b) vs 1/n at n-branch of the G-FET under = −60 V. The retrieved parameters are = 9.33 × 10^{11} cm^{−2}, slope = 9.63 × 10^{15} Ω cm^{2}, = 1.83 kΩ. (c) dependent total channel resistance calculated from Fig. 1(c) under = 60 V. (d) vs 1/n at p-branch of G-FET under = −60 V. The retrieved parameters are = 1.04 × 10^{12} cm^{−2}, slope = 8.84 × 10^{15} Ω cm^{2}, = 2.36 kΩ.

## Tables

Extracted parameters of G-FET under different back gate voltages.

Extracted parameters of G-FET under different back gate voltages.

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