• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.2
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• pp.87-91
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• 2013

Carbon-nanotube field-effect transistors (CNFETs) have drawn wide attention as one of the potential substitutes for metal-oxide-semiconductor field-effect transistors (MOSFETs) in the sub-10-nm era. Output characteristics of coaxially gated CNFETs were simulated using FETToy simulator to reveal the dependence of drain current on the nanotube diameter and gate oxide thickness. Nanotube diameter and gate oxide thickness employed in the simulation were 1.5, 3, and 6 nm. Simulation results show that drain current becomes large as the diameter of nanotube increases or insulator thickness decreases, and nanotube diameter affects the drain current more than the insulator thickness. An equation relating drain saturation current with nanotube diameter and insulator thickness is also proposed.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.1
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• pp.106-111
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• 2016

Thermal noise generated in the electrolyte is modeled for the electrolyte-oxide-semiconductor field-effect transistors. Two noise sources contribute to output noise currents. One is the thermal noise generated in the bulk electrolyte region, and the other is the thermal noise from the double-layer region at the electrolyte-oxide interface. By employing two slightly-different equivalent circuits for two noise current sources, the power spectral density of output noise current is calculated. From the modeling and simulated results, the bulk electrolyte thermal noise dominates the double-layer thermal noise. Electrolyte thermal noise are computed for three different concentrations of NaCl electrolyte. The derived formulas give a good agreement with the published experimental data.

• ETRI Journal
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• v.39 no.2
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• pp.284-291
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• 2017

Drain-induced barrier lowering (DIBL) is one of the main parameters employed to indicate the short-channel effect for nano metal-oxide semiconductor field-effect transistors (MOSFETs). We propose a new physical model of the DIBL effect under two-dimensional approximations based on the energy-conservation equation for channel electrons in FETs, which is different from the former field-penetration model. The DIBL is caused by lowering of the effective potential barrier height seen by the channel electrons because a lateral channel electric field results in an increase in the average kinetic energy of the channel electrons. The channel length, temperature, and doping concentration-dependent DIBL effects predicted by the proposed physical model agree well with the experimental data and simulation results reported in Nature and other journals.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.1
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• pp.88-92
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• 2010

Bottom gate and top gate field-effect transistor based carbon nanotube(CNT) were fabricated by CMOS process. Carbon nanotube directly grown by thermal chemical vapor deposition(CVD) using Ethylene ($C_2H_4$) gas at $700^{\circ}C$. The growth properties of CNTs on the device were analyzed by SEM and AFM. The electrical transport characteristics of CNT FET were investigated by I-V measurement. Transport through the nanotubes is dominated by holes at room temperature. By varying the gate voltage, bottom gate and top gate field-effect transistor successfully modulated the conductance of FET device.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.6
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• pp.551-555
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• 2013

Linearity characteristics of hetero-gate-dielectric tunneling field-effect transistors (HG TFETs) have been compared with those of high-k-only and $SiO_2$-only TFETs in terms of IIP3 and P1dB. It has been observed that the optimized HG TFETs have higher IIP3 and P1dB than high-k-only and $SiO_2$-only TFETs. It is because HG TFETs show higher transconductance ($g_m$) and current drivability than $SiO_2$-only TFETs and $g_m$ less sensitive to gate voltage than high-k-only TFETs.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.4
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• pp.383-389
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• 2004

Magnetic refrigeration is based on the magnetocaloric effect (MCE) - the ability of some materials to heat up when magnetized and cool down when removed from the magnetic field. The available techniques for studying the MCE we: (1) direct measurements by monitoring the change in the material's temperature during the application or removal of the magnetic field; and (2) indirect calculations from the experimental data of magnetization and/or specific heat as a function of the temperature and magnetic field. The MCE of gadolinium (Gd) has been demonstrated by direct measurements of temperature change, and isothermal magnetic entropy changes and adiabatic temperature changes have been calculated.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1169-1173
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• 2015

This paper presents vertical carbon nanotube (CNT) field effect transistors (FETs). For the first time, the author successfully fabricated vertical CNT-based FETs on an anodized aluminum oxide (AAO) template by using atomic layer deposition (ALD). Single walled CNTs were vertically grown and aligned with the vertical pores of an AAO template. By using ALD, a gate oxide material (Al₂O₃) and a gate metal (Au) were centrally located inside each pore, allowing the vertical CNTs grown in the pores to be individually gated. Characterizations of the gated/vertical CNTs were carried and the successful gate integration with the CNTs was confirmed.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.387.1-387.1
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• 2014

A new class of temperature-sensing materials is demonstrated along with their integration into transparent and flexible field-effect transistor (FET) temperature sensors with high thermal responsivity, stability, and reproducibility. The novelty of this particular type of temperature sensor is the incorporation of an R-GO/P(VDF-TrFE) nanocomposite channel as a sensing layer that is highly responsive to temperature, and is optically transparent and mechanically flexible. Furthermore, the nanocomposite sensing layer is easily coated onto flexible substrates for the fabrication of transparent and flexible FETs using a simple spin-coating method. The transparent and flexible nanocomposite FETs are capable of detecting an extremely small temperature change as small as $0.1^{\circ}C$ and are highly responsive to human body temperature. Temperature responsivity and optical transmittance of transparent nanocomposite FETs were adjustable and tuneable by changing the thickness and R-GO concentration of the nanocomposite.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.34 no.10
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• pp.399-406
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• 1985

In this paper transparent PLZT ceramics for the composition of 9/65/35 (La/Zr/Ti ) are fabricated using hotpress and the possibility of application to optical shutter is examined by obtaining the On-Off characteristics of specimens. The ferroelectric E-P hysteresis loop exhibits slim loop suitable for the quadratic electrooptic effect. Measurements of the electrooptic effect show that specimens have the quadratic electrooptic effect but the light intensities as functions of electric field exhibit butterfly type hysteresis curves because of its slightly large saturation remanent polarization and coercive field. On-Off characteristics are obtained by electric fields of-6 kv/cm and +2kv/cm. As a result of experiments, 9/65/35 PLZT ceramics can be applied to optical shutter but construction with other composition which has more slim hysteresis loop is desired for obtaining the Off state by zero electric field.

• Journal of Sensor Science and Technology
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• v.16 no.4
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• pp.313-318
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• 2007

Single-wall carbon nanotube field-effect transistors (SWCNT FETs) of top gate structure were fabricated in a conventional metal-oxide-semiconductor field effect transistor (MOSFET) with gate electrodes above the conduction channel separated from the channel by a thin $SiO_{2}$ layer. The carbon nanotubes (CNTs) directly grown using thin Fe film as catalyst by thermal chemical vapor deposition (CVD). These top gate devices exhibit good electrical characteristics, including steep subthreshold slope and high conductance at low gate voltages. Our experiments show that CNTFETs may be competitive with Si MOSFET for future nanoelectronic applications.