• Journal of the Optical Society of Korea
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• 제17권6호
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• pp.543-547
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• 2013

A temperature dependent (10K-290K) photoluminescence (PL) study for two differently prepared ZnO thin films (as-grown and O-plasma treated) is presented. Four characteristic peaks were identified for both samples: (i) neutral donor-bound excitons ($D^oX$), (ii) two electron satellites (TES), (iii) phonon replica of $D^oX$ ($D^oX$-1LO), and (iv) donor-acceptor pair transition (DAP). As the sample temperature increased, $D^oX$-1LO and DAP transitions became indistinct. This was accompanied by newly-rising emission of free electron-acceptor transitions (e, $A^o$). The spectral evolution with temperature for as-grown samples also showed the optical emission from free excitons, which became dominant at higher temperatures. Some features related to O-plasma were identified in PL spectra: (i) different positions of TES transitions (28meV lower than $D^oX$ for as-grown samples and 35meV for O-plasma treated samples), (ii) the decrease of spectral intensity in both emissions of $D^oX$ and DAP after O-plasma treatment, and (iii) no noticeable transition from free excitons after the O-plasma treatment.

• 전기학회논문지
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• 제67권12호
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• pp.1619-1625
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• 2018

Portable electronic devices secondary batteries can cause fire and explosion due to micro-current change in addition to the situation of short-circuit inrush current, safety can not be secured with a general operation limited current fuse. Therefore, in secondary battery, it is necessary for the protector to satisfy both the limit current type operation in the open-short-circuit inrush current and the current detection operation characteristic in the micro current change situation and for this operation, a fuse for the current detection type secondary battery protection circuit can be applied. The purpose of this study is to design a protection device that operates stably in the hazardous situation of small capacity secondary battery for portable electronic devices through the design of low melting fuse elements alloy of sensing type fuse and secures stability in abnormal current state. As a result of the experiment, I-T and V-T operation characteristics are satisfied in a the design of the alloy of the current sensing type self-contained low melting point fuse and the resistance of the heating resistor. It is confirmed that it can prevent accidents of short circuit over-current and micro current change of secondary battery.

• 대한전자공학회논문지TE
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• 제39권1호
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• pp.9-15
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• 2002

본 논문은 청색 유기 EL 소자를 진공증착법으로 제작하여 그 특성을 분석하였다. 발광층 물질(A1q/sub 3/)에 게스트물질(Type I-TPB와 Type II-DPA)의 도핑농도(0.5∼2 wt%)를 변화시켜 청색발광소자를 제작하여 전기적, 광학적 특성을 조사하였다. Alq3에 도펀트의 농도를 증가함에 따라 청색에 해당하는 색좌표 점으로 이동하였다. Type I이 Type II의 경우보다 동작개시전압 및 구동전압이 낮게 나타났으며 휘도에서는 Type II가 밝게 나타났다. Alq/sub 3/에 DPA(2wt%)를 도펀트로 사용한 소자의 경우 인가전압 15V에서 휘도는 1282cd/m/sup 2/, 최대발광 파장은 476nm, 색좌표는(0.1273, 0.0672)으로 우수한 특성을 나타내었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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• pp.163-166
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• 2002

We investigated structural and electrical properties of Metal-Oxide-Semiconductor(MOS) structure using Hafnium $oxide(HfO_{2})$ as high-k gate dielectric material. $HfO_{2}$ films are ultrathin gate dielectric material witch have a thickness less than 2.0nm， so it is spotlighted to be substituted $SiO_{2}$ as gate dielectric material. In this paper We have grown $HfO_{2}$ films with pt electrode on P-type Silicon substrate by RF magnetron sputtering system using $HfO_{2}$ target and oserved the property of semiconductor-oxide interface. Using pt electrode, it is necessary to be annealed at ${300^{\circ}C}$. This process is to increase an adhesion ratio between $HfO_{2}$ films with pt electrode. In film deposition process, the deposition time of $HfO_{2}$ films is an important parameter. Structura1 properties are invetigated by AES depth profile, and electrical properties by Capacitance-Voltage characteristic. Interface trap density are measured to observe the interface between $HfO_{2}$ with Si using High-frequency(1MHz) C-V and Quasi - static C-V characteristic.

• 반도체디스플레이기술학회지
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• 제7권2호
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• pp.13-17
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• 2008

In this paper, in order to get the characteristics of the lithium secondary cell, such as charge and discharge characteristic, temperature characteristic, self-discharge characteristic and the capacity recovery rate etc, we build a thermal model that estimate the impedance of battery by experiment & simulation. In this one-dimensional model, Seven governing equations are made to solve seven variables c, $c_s,\;\Phi_1,\;\Phi_2,\;i_2$, j and T. The thermal model parameters used in this model have been adjusted according to the experimental data measured in the laboratory. The result(Voc, Impedance) of this research can be used in BMS(Battery Management System), so an efficient method of using battery is developed.

• 전기전자학회논문지
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• 제22권2호
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• pp.488-490
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• 2018

본 연구에서는 급격한 스위칭 특성을 달성하기 위해 싱글단일-게이트 실리콘 채널에서 전하 캐리어의 양의 피드백을 이용하는 새롭게 설계된 피드백 전계 효과 트랜지스터를 제안한다. 에너지 밴드 다이어그램, I-V 특성, 문턱전압 기울기 및 on/off 전류 비는 TCAD 시뮬레이터를 이용하여 분석한다. 피드백 전계 효과 트랜지스터의 중요한 특징 중 하나인 히스테리시스의 특성을 보기 위해 게이트 절연막 물질과 게이트 전극물질을 변경하여 시뮬레이션을 진행했다. 이러한 특성변화는 피드백 전계효과 트랜지스터의 문턱전압 ($V_{TH}$)을 변화시켰고, 메모리 윈도우 폭이 작아지는 현상을 보였다.

• 한국재료학회지
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• 제29권7호
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• pp.456-462
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• 2019

ZnO thin-films are grown on a p-Si(111) substrate by RF sputtering. The effects of growth temperature and $O_2$ mixture ratio on the ZnO films are investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and room-temperature photoluminescence (PL) measurements. All the grown ZnO thin films show a strong preferred orientation along the c-axis, with an intense ultraviolet emission centered at 377 nm. However, when $O_2$ is mixed with the sputtering gas, the half width at half maximum (FWHM) of the XRD peak increases and the deep-level defect-related emission PL band becomes pronounced. In addition, an n-ZnO/p-Si heterojunction diode is fabricated by photolithographic processes and characterized using its current-voltage (I-V) characteristic curve and photoresponsivity. The fabricated n-ZnO/p-Si heterojunction diode exhibits typical rectifying I-V characteristics, with turn-on voltage of about 1.1 V and ideality factor of 1.7. The ratio of current density at ${\pm}3V$ of the reverse and forward bias voltage is about $5.8{\times}10^3$, which demonstrates the switching performance of the fabricated diode. The photoresponse of the diode under illumination of chopped with 40 Hz white light source shows fast response time and recovery time of 0.5 msec and 0.4 msec, respectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 C
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• pp.1851-1853
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• 2004

The important consideration in laboratory designing and construction of the artificial pollution testing facilities including 300kV, 1800kVA AC test system, which enable to test and evaluate the UHV dielectric performance of power insulators up to transmission class, has been dealt in this paper. To evaluate the performance characteristics against contamination for various power installation, especially for the insulators and kinds of bushings, brief investigation and an analysis of test objects and related international codes and standards have been conducted. With the special consideration concerning other matters in designing of these testing facilities have been described with the fixed ratings and references.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1513-1514
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• 2006

In this paper, there have been brief review about the important consideration in laboratory planning and construction of the artificial pollution testing facilities including 300 kV, 1800 kVA AC test system, which enable to lest and evaluate the UHV dielectric performance of power insulators up to transmission class. Also it is described simply about its trial running of the whole test system. To evaluate the performance characteristics against contamination for various power installation, especially for the insulators and kinds of bushings, brief investigation and an analysis of test objects and related international codes and standards have been conducted.

• JSTS:Journal of Semiconductor Technology and Science
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• 제11권3호
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• pp.153-161
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• 2011

In this work, we report the physics-based SPICE model of amorphous oxide semiconductor (AOS) thin-film transistors (TFTs) and demonstrate the SPICE simulation of amorphous InGaZnO (a-IGZO) TFT inverter by using Verilog-A. As key physical parameter, subgap density-of-states (DOS) is extracted and used for calculating the electric potential, carrier density, and mobility along the depth direction of active thin-film. It is confirmed that the proposed DOS-based SPICE model can successfully reproduce the voltage transfer characteristic of a-IGZO inverter as well as the measured I-V characteristics of a-IGZO TFTs within the average error of 6% at $V_{DD}$=20 V.