• Journal of the Korean Vacuum Society
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• v.2 no.3
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• pp.325-330
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• 1993

실리콘 gate의 MOS 전자 턴넬링 전극을 구성하여 그 특성을 조사하였다. 전자 방출은 전 gate 영역에서 MOS diode의 전위차를 지나는 턴넬링에 의하여 일어나고 안정하였다. 측정된 전류에서 산화막과 gate에서의 열전자의 충돌을 연구하였다. 방출된 전류는 압력에 관계없이 일정하였다.

• 한국초전도학회:학술대회논문집
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• v.13
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• pp.10-10
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• 2003

• Proceedings of the Korean Magnestics Society Conference
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• 2005.12a
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• pp.196-196
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• 2005

• Journal of Sensor Science and Technology
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• v.5 no.5
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• pp.1-10
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• 1996

Solar cells made of the edge-defined film-fed growth Si are characterized using current-voltage, surface photovoltage, electron beam induced current, electron microprobe, scanning electron microscopy, and electron backscattering. The weak temperature dependence of the I-V curves in the EFG solar cells is due to a voltage variable shunt resistance giving higher diode ideality factors than the ideal one. The voltage variable shunt resistance is modeled by a modified recombination mechanism which includes carrier tunneling to distributed impurity energy states in the band gap within the space-charge region. The junction integrity and the substrate quality are characterized simultaneously by combining I-V and surface photovoltage (SPV) measurements. The diode ideality factors and the surface photovoltages characterize the junction integrity while the SPV diffusion lengths characterizes the substrate quality. Most of the measured samples show the voltage variable shunt resistance although how serious it is depends on the solar cell efficiency. The voltage variable shunt resistance is understood as one of the most important factors of the degradation of EFG solar cells.

• Journal of the Korean Vacuum Society
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• v.20 no.1
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• pp.57-62
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• 2011

We have studied the electrical and magnetic transport properties of tunneling device with FePt magnetic quantum dots. The FePt nanoparticles with a diameter of 8~15 nm were embedded in a $SiO_2$ layer through thermal annealing process at temperature of $800^{\circ}C$ in $N_2$ gas ambient. The electrical properties of the tunneling device were characterized by current-voltage (I-V) measurements under the perpendicular magnetic fields at various temperatures. The nonlinear I-V curves appeared at 20 K, and then it was explained as a conductance blockade by the electron hopping model and tunneling effect through the quantum dots. It was measured also that the negative magneto-resistance ratio increased about 26.2% as increasing external magnetic field up to 9,000 G without regard for an applied electric voltage.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.387-387
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• 2013

Currently, the flash memory and the dynamic random access memory (DRAM) have been used in a variety of applications. However, the downsizing of devices and the increasing density of recording medias are now in progress. So there are many demands for development of new semiconductor memory for next generation. Magnetic random access memory (MRAM) is one of the prospective semiconductor memories with excellent features including non-volatility, fast access time, unlimited read/write endurance, low operating voltage, and high storage density. MRAM is composed of magnetic tunnel junction (MTJ) stack and complementary metal-oxide semiconductor (CMOS). The MTJ stack consists of various magnetic materials, metals, and a tunneling barrier layer. Recently, MgO thin films have attracted a great attention as the prominent candidates for a tunneling barrier layer in the MTJ stack instead of the conventional Al2O3 films, because it has low Gibbs energy, low dielectric constant and high tunneling magnetoresistance value. For the successful etching of high density MRAM, the etching characteristics of MgO thin films as a tunneling barrier layer should be developed. In this study, the etch characteristics of MgO thin films have been investigated in various gas mixes using an inductively coupled plasma reactive ion etching (ICPRIE). The Cl2/Ar, CH3OH/Ar, and CH4/Ar gas mix were employed to find an optimized etching gas for MgO thin film etching. TiN thin films were employed as a hard mask to increase the etch selectivity. The etch rates were obtained using surface profilometer and etch profiles were observed by using the field emission scanning electron microscopy (FESEM).

• Polymer(Korea)
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• v.25 no.2
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• pp.293-301
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• 2001

Electrically conductive carbon fiber/high density polyethylene (CF/HDPE) composite films were fabricated by new method, so called electron-ion technology (EIT) and the effects of CF epoxy sizing on the volumetric resistivity. tensile strength and interphase properties of the films were investigated. While epoxy sizing increased conductivity of composite films resulting from enhanced tunneling effect it reduced interphase adhesion between CF and HDPE because polar epoxy sizing and nonpolar HDPE are incompatible. Consequently epoxy sized CF(CF(S)) caused significant reduction in the volumetric resisitivity and tensile strength of composite films when compared with unsized CF(CF(U)). Epoxy sizing reduced nucleating efficiency of CF(S), therefore CF(S)/HDPE composite films showed nonuniform transcrystalline layer when compared with CF(U)/HDPE composite films.

• ETRI Journal
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• v.26 no.6
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• pp.669-672
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• 2004

To improve the operation error caused by the thermal fluctuation of electrons, we propose a novel single-electron pass-transistor logic circuit employing a multiple-tunnel junction (MTJ) scheme and modulate a parameters of an MTJ single-electron tunneling device (SETD) such as the number of tunnel junctions, tunnel resistance, and voltage gain. The operation of a 3-MTJ inverter circuit is simulated at 15 K with parameters $C_g=C_T=C_{clk}=1\;aF,\;R_T=5\;M{\Omega},\;V_{clk}=40\;mV$, and $V_{in}=20\;mV$. Using the SETD/MOSFET hybrid circuit, the charge state output of the proposed MTJ-SETD logic is successfully translated to the voltage state logic.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.823-826
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• 2001

In the initial process of photosynthesis, a biological electron transfer system, photoelectric conversion occurs and then long-range electron transfer takes place very efficiently in one direction through the biomolecules. The metal/insulator/metal structured device consisting of GFP, viologen, cytochrome c hetero-thin film was presented based on the biomimesis. GFP, viologen, and cytochrome c was used as an electron sensitizer, a mediator, and an electron acceptor. Cytochrome c molecules and viologen molecules were deposited by Langmuir-Blodgett (LB) technique, and GFP molecules were adsorbed by self-assembly method (SAM). Surface morphology of hetero-thin film was analyzed by scanning tunneling microscopy (STM). Local photoswitching effects of a proposed photodiode were verified by current-voltage measurements using hybrid STM/I-V measurement system.

• Journal of Electrical Engineering and Technology
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• v.1 no.3
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• pp.366-370
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• 2006

We investigated the negative differential resistance (NDR) property of self-assembled 4,4-di(ethynylphenyl)-2'-nitro-l-(thioacetyl)benzene ('nitro-benzene'), which has been well known as a conducting molecule [1], Self-assembly monolayers (SAMs) were prepared on Au (111), which had been thermally deposited onto pre-treated $(H_2SO_4: H_2O_2=3:1)$ Si, The Au substrate was exposed to a 1mM solution of 1-dodecanethiol in ethanol for 24 hours to form a monolayer. After thorough rinsing of the sample, it was exposed to a $0.1{\mu}M$ solution of nitro-benzene in dimethylformamide (DMF) for 30 min and kept in the dark during immersion to avoid photo-oxidation. Following the assembly, the samples were removed from the solutions, rinsed thoroughly with methanol, acetone, and $CH_2Cl_2$, and finally blown dry with $N_2$. Under these conditions, we measured the electrical properties of SAMs using ultra high vacuum scanning tunneling microscopy (UHV-STM) and scanning tunneling spectroscopy (STS) [2]. As a result, we confirmed the properties of NDR in between the positive and negative region.