• Title/Summary/Keyword: capacitance-voltage characteristics

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Electrical Properties of CuPc FET with Different Substrate Temperature

  • Lee, Ho-Shik;Park, Yong-Pil;Cheon, Min-Woo
    • Transactions on Electrical and Electronic Materials
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    • v.8 no.4
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    • pp.170-173
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    • 2007
  • Organic field-effect transistors (OFETs) are of interest for use in widely area electronic applications. We fabricated the organic field-effect transistor based a copper phthalocyanine (CuPc) as an active layer on the silicon substrate. The CuPc FET device was made a topcontact type and the substrate temperature was room temperature and $150^{\circ}C$. The CuPc thickness was 40 nm, and the channel length was $50{\mu}m$, channel width was 3 mm. We observed the typical current-voltage (I-V) characteristics and capacitance-voltage (C-V) in CuPc FET and we calculated the effective mobility with each device. Also, we observed the AFM images with different substrate temperature.

Capacitance Characteristics of GaAs MESFET will Temperatures (온도 변화에 따른 GaAs MESFET의 정전용량에 대한 연구)

  • 박지홍;김영태;원창섭;안형근;한득영
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.11a
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    • pp.445-448
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    • 1999
  • In this Paper, we present simple physical model of the Capacitance characteristics for GaAs MESFET\`s in wide temperatures. In this model, gate-source and gate-drain capacitances are represented by analytical expressions which are classified into three different regions for bias voltage. This model contained the temperature dependent variable that is the built-in voltage and the depletion width. Using the equations obtained in this work a submicron gate length MESFET has simulated and theoretical result are in good agreement with the experimental measurement.

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Electrochemical Characteristics of Aqueous Polymeric Gel Electrolyte for Supercapaictor (수퍼커패시터용 수용성 고분자 젤 전해질의 전기화학적 특성)

  • Kim, Han-Joo;Ishikawa, Masashi;Morita, Masayuki;Park, Soo-Gil
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11b
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    • pp.93-96
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    • 2001
  • We have reported to make nanostructured cobalt oxide electrode that have large capacitance over than 400F/g (specific capacitance) and good cycleability. But, It had serious demerits of low voltage range under 0.5V and low power density. Therefore, we need to increase voltage range of cobalt oxide electrode. we report here on the electrochemical properties of sol-gel-derived nanoparticulate cobalt xerogel in 1M KOH solution and aqueous polymeric gel electrolyte. In solution electrolyte, cobalt oxide electrode had over than 250F/g capacitance consisted of EDLC and pseudocapacitance. In gel electrolyte, cobalt oxide electrode had around l00F/g capacitance. This capacitance was only surface EDLC. In solution electrolyte, potassium ion as working ion reacted with both of layers easily. However, In gel electrolyte, reacted with only surface-active layer. Its very hard to reach resistive layer. So, we have studied on pretreatment of electrode to contain working ions easily. We'll report more details.

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Electrochemical Characteristics of Aqueous Polymeric Gel Electrolyte for Supercapacitor (수퍼커패시터용 수용성 고분자 젤 전해질의 전기화학적 특성)

  • ;Masashi ISHIKAWA;Masayuki MORITA
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11a
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    • pp.93-96
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    • 2001
  • We have reported to make nanostructured cobalt oxide electrode that have large capacitance over than 400F/g (specific capacitance) and good cycleability. But, It had serious demerits of low voltage range under 0.5V and low power density. Therefore, we need to increase voltage range of cobalt oxide electrode. we report here on the electrochemical properties of sol-gel-derived nanoparticulate cobalt xerogel in 1M KOH solution and aqueous polymeric gel electrolyte. In solution electrolyte, cobalt oxide electrode had over than 250F/g capacitance consisted of EDLC and pseudocapacitance. In gel electrolyte, cobalt oxide electrode had around 100F/g capacitance. This capacitance was only surface EDLC. In solution electrolyte, potassium ion as working ion reacted with both of layers easily. However, In gel electrolyte, reacted with only surface-active layer. Its very hard to reach resistive layer. So, e have studied on pretretmetn of electrode to contain working ions easily. We'll report more details.

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Characteristics Analysis of ZVS-HB Type High Frequency Resonant Inverter According to the Variable Capacitance of the DC Voltage Source Separation Capacitor (직류 전원 분할용 커패시터의 용량 변화에 따른 ZVS-HB형 고주파 공진 인버터의 특성해석)

  • Mun, Chang-Su;Kim, Jong-Hae;Kim, Dong-Hui;O, Seung-Hun;Sim, Gwang-Yeol;Min, Byeong-Jae
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.49 no.5
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    • pp.352-357
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    • 2000
  • This paper presents about an example of circuit design and characteristics of inverter according to the variable capacitance of the DC voltage source separation capacitor used in ZVS-HB type high frequency resonant inverter. The soft switching technology known as ZVS is used to reduce turn off loss at switching. In the event the capacitance of the DC voltage source separation capacitor is varied, the analysis of inverter circuit has generally described by using normalized parameter and operating characteristics have been evaluated in terms of switching frequency and parameters. According to the calculated characteristics value, a method of the circuit designs and operating characteristic of the inverter is also presented in this paper. In addition, this paper proves the validity of theoretical analysis through the experiment. This proposed inverter shows that it can be practically used in future as power source system for the lighting equipment of discharge lamp, DC-DC converter etc.

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Experimental Analysis on Temperature Compensation of Capacitive Voltage Divider for a Pulsed High Voltage Measurement (고전압 펄스신호 측정용 분압기의 온도보상에 관한 실험)

  • Jang, S.D.;Son, Y.G.;Kwon, S.J.;Oh, J.S.;Cho, M.H.
    • Proceedings of the KIEE Conference
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    • 2005.07b
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    • pp.1530-1533
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    • 2005
  • Total 12 units of high power klystron-modulator systems as microwave source is under operation for 2.5-GeV electron linear accelerator in Pohang Light Source(PLS) linac. RF power and beam power of klystron are precisely measured for the effective control of electron beam. A precise measurement and measurement equipment with good response characteristics are required for this. Input power of klystron is calculated from the applied voltage and the current on its cathode. Tiny measurement error severely effects RF output power value of klystron. Therefore, special care is needed to measure precise beam voltage. Capacitive voltage divider(CVD) unit is intended for the measurement of beam voltage of 400 kV generated from the pulsed klystron-modulator system. Main parameter to determine the standard capacitance in the high arm of CVD is dielectric constant of insulation oil. Therefore CVD should be designed to have a minimum capacitance variation due to voltage, frequency and temperature in the measurement range. This paper will discuss the analysis of capacitive voltage divider for a pulsed high-voltage measurement, and the empirical relations between capacitance and oil temperature variation.

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High Voltage Transformer Design using Self-Resonant Characteristics of Transformer (트랜스포머의 자가공진 특성을 이용한 고전압 트랜스포머 설계)

  • Lee, Sueng-Hwan;Cho, Dae-Kweon
    • Journal of IKEEE
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    • v.18 no.1
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    • pp.31-36
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    • 2014
  • In this paper, self-resonant characteristics of transformers were analyzed in accordance with changes of characteristics regarding to the stray capacitance, the volume of winding and the winding ratio were organized by formulas. Generally, the stray capacitance is considered as an unnecessary factor in processing transformers design as well as one of the inherent characteristics. In particular, these characteristics can be appeared clearly in the high frequency driving and Electrical resonance occurs in transformer, according to coupling with a magnetic factor at a particular frequency. In the case of high-voltage output applications, such as medical equipments, It is required to output high-voltage gain. Therefor, If Self-Resonant Characteristic is applied to High-Voltage transformer design, Not only the transformer and circuit but also related the system size can be reduced. So we propose it as one of additional high voltage transformer design methods.

Capacitance-Voltage Characteristics of MIS Capacitors Using Polymeric Insulators

  • Park, Jae-Hoon;Choi, Jong-Sun
    • Journal of Information Display
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    • v.9 no.2
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    • pp.1-4
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    • 2008
  • In this study, we investigate the capacitance-voltage (C-V) characteristics of metal-insulator-semiconductor (MIS) capacitors consisting of pentacene, as an organic semiconductor, and polymeric insulators such as poly(4-vinylphenol) (PVP) orpolystyrene (PS) prepared by spin-coating process, to analyze the interfacial characteristics between pentacene and polymeric insulators. Compared with the device with PS, the MIS capacitor with PVP exhibited a pronounced shift in the flat-band voltage according to the bias sweep direction. This hysteric feature in the C-V characteristics is thought to be attributed to the trapped charges at the interface between pentacene and PVP owing to the hydrophilicity of PVP. From the experimental results, we can conclude that surface polarity of polymeric insulator has a critical effect on the interfacial properties, thereby affecting the bias stability of organic thin-film transistors.

Capacitive Voltage Divide for a Pulsed High-Voltage Measurement (펄스형 고전압 측정용 용량성 분압기)

  • Jang Sung-Duck;Son Yoon-Kyoo;Kwon Sei-Jin;Oh Jong-Seok;Cho Moo-Hyun
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.54 no.2
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    • pp.63-68
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    • 2005
  • Total 12 units of high power klystron-modulator systems as microwave source are under operation for 2.5 GeV electron linear accelerator in Pohang Light Source (PLS) linac. The klystron-modulator system has an important role for the stable operation to improve an availability statistics of overall system performance of klystron-modulator system. RF power and beam power of klystron are precisely measured for the effective control of electron beam. A precise measurement and measurement equipment with good response characteristics are demanded for this. Input power of klystron is calculated from the applied voltage and the current on its cathode. Tiny measurement error severely effects RF output power value of klystron. Therefore, special care is needed to measure precise beam voltage. Capacitive voltage divider (CVD), which divides input voltage as capacitance ratio, is intended for the measurement of a beam voltage of 400 kV generated from the klystron-modulator system. Main parameter to determine standard capacitance in the high arm of CVD is dielectric constant of insulation oil. Therefore CVD should be designed to have a minimum capacitance variation due to voltage, frequency and temperature in the measurement range. This paper will be present and discuss the design concept and analysis of capacitive voltage divider for a pulsed high-voltage measurement, and the empirical relations between capacitance effects and oil temperature variation.

Capacitance-Voltage Characteristics in the Double Layers of SiO$_2$/Si$_3$N$_4$ (SiO$_2$/Si$_3$N$_4$ 이중 박막의 C-V 특성)

  • Hong, Nung-Pyo;Hong, Jin-Woong
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.52 no.10
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    • pp.464-468
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    • 2003
  • The double layers of $SiO_2$/$Si_3$$N_4$ have superior charge storage stability than a single layer of $SiO_2$. Many researchers are very interested in the charge storage mechanism of $SiO_2$/$Si_3$$N_4$ [1,2]. In this paper, the electrical characteristics of thermal oxide and atmospheric pressure chemical vapor deposition (APCVD) of $Si_4$$N_4$ have been investigated and explained using high frequency capacitance-voltage measurements. Additionally, this paper will describe capacitance-voltage characteristics for double layers of $SiO_2$/$Si_4$$N_4$ by "Athena", a semiconductor device simulation tool created by Silvaco, Inc.vaco, Inc.