• Proceedings of the Korean Vacuum Society Conference
• /
• 2015.08a
• /
• pp.148-148
• /
• 2015

Over the past several years, Colloidal core/shell type quantum dots lighting-emitting diodes (QDLEDs) have been developed for the future of optoelectronic applications. An inverted-type quantum-dot light-emitting-diode (QDLED), employing low work function organic material polyethylenimine ethoxylated(PEIE) (<10 nm)[1] modified ZnO nanoparticles (NPs) as electron injection and transport layer, was fabricated by all solution processing method, instead of electrode in the device. The PEIE surface modifier incorporated on the top of the ZnO NPs film, facilitates the enhancement of both electorn injection into the CdSe-ZnS QD emissive layer by lowering the workfunction of ZnO from 3.58eV to 2.87eV and charge balance on the QD emitter. In this inverted QDLEDs, blend of poly (9,9-di-n-octyl-fluorene-alt-benzothiadiazolo) and poly(N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] are used as hole transporting layer (HTL) to improve hole transporting property. At the operating voltage of 7.5 V, the QDLED device emitted spectrally orange color lights with high luminance up to 11110 cd/m2, and showed current efficiency of 2.27 cd/A.[2]

• Korean Journal of Materials Research
• /
• v.19 no.11
• /
• pp.613-618
• /
• 2009

We designed new compositions for lead free and low temperature sealing glass frit of $ZnO-V_2O_5-P_2O_5$ system, which can be used for PDP (Plasma Display Panel) or other electronic devices. The $ZnO-V_2O_5-P_2O_5$ system can be used as a sealing material at temperatures even lower than 430$^{\circ}C$. This system, however, showed lower bonding strength with glass substrate compared to commercialized Pb based sealing materials. So, we added $TiO_2$ as a promoter for bonding strength. We examined the effect of $TiO_2$ addition on sealing behaviors of $ZnO-V_2O_5-P_2O_5$ glasses with the data for flow button, wetting angle, temporary & permanent residual stress of glass substrate, EPMA analysis of interface between sealing materials and glass substrate, and bonding strength. As a result, sealing characteristics of $ZnO-V_2O_5-P_2O_5$ system glasses were improved with $TiO_2$ addition, but showed a maximum value at 5 mol% $TiO_2$ addition. The reason for improved bonding characteristics was considered to be the chemical interaction between glass substrate and sealing glass, and structural densification of sealing glass itself.

• 전자공학회논문지 IE
• /
• v.47 no.2
• /
• pp.13-20
• /
• 2010

This paper describes a current mode PWM DC-DC converter IC for battery charger and supply power converter for portable electronic devices. The maximum supply voltage of IC is 40[V] and 2.8[V]~330[V] DC input power is converted to higher or programmed DC voltage according to external resistor ratio or wire winding ratio of transformer. The maximum supply output current is 3[A] over and voltage error of output node is within 3[%]. The whole circuit needed current mode PWM DC-DC converter circuit is designed. The package dimensions and number of external parts are minimized in order to get a smaller hardware size. The power consumption is smaller then 1[mW] at stand by period with supply voltage of 3.6[V] and maximum energy conversion efficiency is about 86[%]. This device has been designed in a 0.6[um] double poly, double metal 40[V] CMOS process and whole chip size is 2100*2000 [um2].

• 전자공학회논문지 IE
• /
• v.44 no.2
• /
• pp.1-7
• /
• 2007

The increasing high frequency capabilities of CMOS have resulted in increased RF and analog design in CMOS. Design of RF and analog circuits depends critically on device S-parameter characteristics, magnitude of real and imaginary components and their behavior as a function of frequency. Utilization of scaled high performance CMOS technologies poses challenges as concerns for reliability degradation mechanisms increase. It is important to understand and quantify the effects of the reliability degradation mechanisms on the S-parameters and in turn on small signal model parameters. Various physical effects influencing small-signal parameters, especially the transconductance and capacitances and their degradation dependence, are discussed in detail. The measured S-parameters of H-gate and T-gate devices in a frequency range from 0.5GHz to 40GHz. All intrinsic and extrinsic parameters are extracted from S-parameters measurements at a single bias point in saturation. In this paper we discuss the analysis of the small signal equivalent circuits of RF SOI MOSFET's verificated for the purpose of exacting the change of parameter of small signal equivalent model followed by device flame.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.1 no.1
• /
• pp.75-82
• /
• 1987

Application of conventional phase controlled power electronic circuits causes reduced power factor and increased harmonic component in the electric sources. Therefore, an Optimal PWM strategy has been investigated here in order to reduce to a large extent these effects mentioned. Optimal PWM converter has been to minimize the rms harmonic current in the sources and has been found to have a duality with Optimal PWM inverter. The voltage patterns of Optimal PWM Inverters are governed by the same switching patterns and control laws as the current patterns for Optimal PWM converter. The improvement requires switching devices having a high speed capability. While this formerly did require thyristors with force commutation circuits, today this feature is easily implemented by using power Transistor or GTOs. The control laws for minimizing the rms harmonics current in the source, the circuits and the results are shown in the paper.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2003.09a
• /
• pp.272-275
• /
• 2003

This paper presents the role and its function of Tool server. MPEG-21 means multimedia framework for delivery and consumption of multimedia which is being discussed in ISO/IEC 21000. A view of MPEC-21 aims to define multimedia framework to enable transparent use of multimedia resource across a wide range of networks and devices used by different communities. MPEG-21 will enable all-electronic creation delivery and trade of digital multimedia content and transparent usage of various content types on network device. Therefore, we can provide access to information and services from almost anywhere at anytime with various terminals and networks. In order to support multimedia delivery chain that contains content creation, production, delivery and consumption, we need many standards(elements) for identify, describe, manage and protect the content. Thus, we define Digital Item Player(DIP), Digital Item Adaptation(DIA) server and Tool server as primary objects of MPEG-21 multimedia framework. DIP provides a function which creates and consumes Digital Item(DI) as a kind of a digital object by user. A DI contains both media resources and metadata including rights information. DIA server deals with the usage environment description schema of the user characteristics, terminal and network characteristics and natural environments. DIA server adapts the original DI to the usage environment description sent from the terminal and transmits the adapted DI to the terminal. Tool server searches for a tool requested from DIP or DIA and downloads the best tool to DIP or DIA server. In this paper, we present how Tool sewer is organized and is used among 2 primary objects. The paper is structured as followings: Section 1 briefly describes why MPEG-21 is needed and what MPEG-21 wants. We see requirement that tool server must equip functionally in section 2. The proposed tool server,its structure and its functionality are presented in section 3. Section 4 explains a scenario that tool server transmits tool to DIP and shows the experimental result. The paper concludes in section 5.

• ETRI Journal
• /
• v.30 no.3
• /
• pp.383-393
• /
• 2008

The etching mechanism of $ZrO_2$ thin films and etch selectivity over some materials in both $BCl_3$/Ar and $BCl_3/CHF_3$/Ar plasmas are investigated using a combination of experimental and modeling methods. To obtain the data on plasma composition and fluxes of active species, global (0-dimensional) plasma models are developed with Langmuir probe diagnostics data. In $BCl_3$/Ar plasma, changes in gas mixing ratio result in non-linear changes of both densities and fluxes for Cl, $BCl_2$, and ${BCl_2}^+$. In this work, it is shown that the non-monotonic behavior of the $ZrO_2$ etch rate as a function of the $BCl_3$/Ar mixing ratio could be related to the ion-assisted etch mechanism and the ion-flux-limited etch regime. The addition of up to 33% $CHF_3$ to the $BCl_3$-rich $BCl_3$Ar plasma does not influence the $ZrO_2$ etch rate, but it non-monotonically changes the etch rates of both Si and $SiO_2$. The last effect can probably be associated with the corresponding behavior of the F atom density.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.8
• /
• pp.285-291
• /
• 2013

In this paper, MOS-Capacitor and MOSFET devices with a Low Level Leakage Current of oxide thickness, channel width and length respectively were to investigate the reliability characterizations mechanism of ultra thin gate oxide films. These stress induced leakage current means leakage current caused by stress voltage. The low level leakage current in stress and transient current of thin silicon oxide films during and after low voltage has been studied from strss bias condition respectively. The stress channel currents through an oxide measured during application of constant gate voltage and the transient channel currents through the oxide measured after application of constant gate voltage. The study have been the determination of the physical processes taking place in the oxides during the low level leakage current in stress and transient current by stress bias and the use of the knowledge of the physical processes for driving operation reliability.

• Journal of Advanced Marine Engineering and Technology
• /
• v.36 no.5
• /
• pp.700-706
• /
• 2012

The core technology of a starting device in the packaged power system is the pinion gear shifting device and to limit the initial starting voltage. Although the conventional products have been used the starting controller using mechanical contactor, these have a big problem such as the uncertainty for the start of starting motor after a pinion gear is completely shifted or the arc demage due to high current. In this study, in order to solve these problems, we designed and fabricated a new product to achieve the safety and reliability as follows: the pinion gear-shifting control circuits to eliminate the uncertainty of the start, the starting control system using semiconductor device to prevent the arc demage of contactor caused by high current, a start safety devices for soft starting of series motor. In addition, we obtained the electrical safety by separating the pinion gear control circuit and the source circuit of motor.

• Analytical Science and Technology
• /
• v.24 no.6
• /
• pp.435-442
• /
• 2011

Polybrominated diphenyl ethers (PBDEs) are a class of brominated flame retardants (BFRs) which have taken much interest recently due to their potential hazardous effects to human body and ecosystem. Many countries and European community prohibits the usage of certain BFRs in electronics and electronic devices (e.g. RoHS). In this perspectives, Korea Research Institute of Standards and Science (KRISS) has designed and practiced proficiency testing programs based on the ISO/IEC 17043 in order to assist laboratory accreditation activities. The programs for interlaboratory comparisons include congeners of PBDE (PBDE-154, 183, 206, 209) in high impact polystyrene (HIPS). A sample bottle that contains 10 g granular HIPS was distributed to 35 participating laboratories and the test results were calculated by the statistical procedure using z-scores to evaluate performance of each laboratory. The results and the laboratory's performance were discussed.