Transconductance Amplification by the Negative Capacitance in Ferroelectric-Gated P3HT Thin-Film Transistor

Jo, Jaesung,Kim, Min Gee,Lee, Hyunjae,Choi, Hyunwoo,Shin, Changhwan Institute of Electrical and Electronics Engineers 2017 IEEE transactions on electron devices Vol.64 No.12

<P>With lots of interest in negative capacitance field-effect transistors for ultralow-power complementary metal–oxide–semiconductor technology, negative capacitance thin-film transistors (NCTFTs) have also received much attention. Although previous studies on NCTFTs were done, the NC effect in organic-based TFTs was not studied yet. In this paper, P(VDF-TrFE) ferroelectric-gated P3HT semiconductor channel TFTs are experimentally demonstrated with solution-based fabrication process. Especially, this paper shed light on the NC effect in the organic-based TFTs. The step-up current-voltage characteristics are repeatedly and reliably observed in diverse TFTs, and then, with the results, transconductance ( <TEX>$g_{m}$</TEX>) amplification implemented by the negative capacitance was delved. Moreover, with the aid of ferroelectric polarization switching, super steep-switching characteristic of the organic-based TFT was experimentally confirmed. These experimental results and discussion would be helpful in understanding NC effects in TFTs.</P>

Impact of temperature on negative capacitance field-effect transistor

Jaesung Jo,Changhwan Shin IET 2015 Electronics letters Vol.51 No.1

<P>A negative capacitance field-effect transistor (FET) with sub-60 mV/decade subthreshold slope (SS) at different temperatures (i.e. 14.8 mV/decade at 300 K, 15.7 mV/decade at 360 K and 24.3 mV/decade at 400 K) is experimentally demonstrated. A detailed account of the fabrication process of a negative capacitor is first introduced, followed by the measurement setup for the negative capacitance FET. The impact of temperature on negative capacitance FETs is investigated: (i) the equation for the internal voltage gain in the FET as a function of temperature is derived using Gibbs free energy and (ii) internal voltage against gate voltage (<I>V</I><SUB>Int</SUB> against <I>V</I><SUB>G</SUB>), internal voltage gain against gate voltage (d<I>V</I><SUB>Int</SUB>/d<I>V</I><SUB>G</SUB> against <I>V</I><SUB>G</SUB>) and drain current against gate voltage (<I>I</I><SUB>D</SUB> against <I>V</I><SUB>G</SUB>) curves at different temperatures are measured. It is confirmed that internal voltage amplification can be achieved using the ferroelectric capacitor. However, the magnitude of the step-up voltage transformation is reduced, i.e. from 9.5 at 300 K to 2.6 at 400 K. Additionally, the SS is slightly increased (i.e. degrading from 14.8 mV/decade at 300 K to 24.3 mV/decade at 400 K) with increasing temperature; however, all SS values are better than the physical limits of SS as dictated by Boltzmann statistics.</P>

Transparent bifacial a-Si:H solar cells employing silver oxide embedded transparent rear electrodes for improved transparency

Jo, Hyunjin,Yang, Jo-Hwa,Lee, Ji-hoon,Lim, Jung-Wook,Lee, Jaesung,Shin, Myunhun,Ahn, Ji-Hoon,Kwon, Jung-Dae Elsevier 2018 SOLAR ENERGY -PHOENIX ARIZONA THEN NEW YORK- Vol.170 No.-

<P><B>Abstract</B></P> <P>We developed a transparent oxide–metal–oxide (OMO) structure using aluminum-doped zinc oxide and oxidized silver (AgO<SUB>x</SUB>) as a transparent electrode of a hydrogenated amorphous silicon (a-Si:H) thin-film solar cell for use in building-integrated photovoltaic (BIPV) windows. The oxygen (O<SUB>2</SUB>) addition (O<SUB>2</SUB> flow rate) was optimized for a metal-to-dielectric intermediate-phase AgO<SUB>x</SUB> OMO to have high transparency and high conductivity, which were confirmed by finite-difference time-domain simulation. Using the AgO<SUB>x</SUB> OMO as a rear electrode, transparent a-Si:H solar cells were fabricated for BIPV window application. The performance of the fabricated cells showed highest bifacial efficiency (b-<I>η</I>) of 7.87% at AgO<SUB>x</SUB> OMO of 1 sccm, and highest average transmittance (<I>T</I> <SUB>500–800</SUB>, i.e., wavelength range: 500–800 nm) of 21.9% at AgO<SUB>x</SUB> OMO of 3 sccm, i.e., improvements from b-<I>η</I> = 7.42% and <I>T</I> <SUB>500–800</SUB> = 18.8% at Ag OMO of 0 sccm. The cell with the optimized AgO<SUB>x</SUB> OMO (3 sccm) achieved b-<I>η</I> = 7.69% and the best figure of merit (product of b-<I>η</I> and <I>T</I> <SUB>500–800</SUB>) of 169%, i.e., 30% higher than the Ag OMO cell (139%). The developed AgO<SUB>x</SUB> OMO electrodes could be used in BIPV windows or in other optical devices requiring both high transparency and high conductivity.</P> <P><B>Highlights</B></P> <P> <UL> <LI> AgO<SUB>x</SUB> is introduced in a transparent oxide-metal-oxide (OMO) structure. </LI> <LI> Oxidization of AgO<SUB>x</SUB> is optimized for high transparency and efficiency of transparent a-Si:H solar cells. </LI> <LI> Optical property of AgO<SUB>x</SUB>-OMO is investigated experimentally and theoretically. </LI> <LI> Bifacial operation property of a-Si:H solar cells was presented. </LI> </UL> </P>

Negative Capacitance in Organic/Ferroelectric Capacitor to Implement Steep Switching MOS Devices

Jo, Jaesung,Choi, Woo Young,Park, Jung-Dong,Shim, Jae Won,Yu, Hyun-Yong,Shin, Changhwan American Chemical Society 2015 NANO LETTERS Vol.15 No.7

<P>Because of the “Boltzmann tyranny” (i.e., the nonscalability of thermal voltage), a certain minimum gate voltage in metal–oxide–semiconductor (MOS) devices is required for a 10-fold increase in drain-to-source current. The subthreshold slope (SS) in MOS devices is, at best, 60 mV/decade at 300 K. Negative capacitance in organic/ferroelectric materials is proposed in order to address this physical limitation in MOS technology. Here, we experimentally demonstrate the steep switching behavior of a MOS devicethat is, SS ∼ 18 mV/decade (much less than 60 mV/decade) at 300 Kby taking advantage of negative capacitance in a MOS gate stack. This negative capacitance, originating from the dynamics of the stored energy in a phase transition of a ferroelectric material, can achieve the step-up conversion of internal voltage (i.e., internal voltage amplification in a MOS device). With the aid of a series-connected negative capacitor as an assistive device, the surface potential in the MOS device becomes higher than the applied gate voltage, so that a SS of 18 mV/decade at 300 K is reliably observed.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2015/nalefd.2015.15.issue-7/acs.nanolett.5b01130/production/images/medium/nl-2015-011302_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl5b01130'>ACS Electronic Supporting Info</A></P>

Negative Capacitance Field Effect Transistor With Hysteresis-Free Sub-60-mV/Decade Switching

Jaesung Jo,Changhwan Shin IEEE 2016 IEEE electron device letters Vol.37 No.3

<P>We demonstrate a nearly hysteresis-free sub-60-mV/decade subthreshold swing (SS) operation in a p-type bulk metal-oxide-semiconductor field-effect transistor externally connected to a ferroelectric capacitor. The SS <60 mV/decade is observed over three orders of magnitude (i.e., 10 pA/mu m similar to 10 nA/mu m of drain current) and at large drain current levels. However, the extent of hysteresis is found to be dstrongly dependent on the drain voltage. At high drain voltages, large hysteresis occurs, indicating the influence of drain voltage in the charge balance with the ferroelectric capacitor.</P>

고출력 엔진 차량에 대한 토크스티어 메커니즘 분석 및 근본 개선안 도출

조재성(Jaesung Jo),박준홍(Joonghong Park),오승철(Seungchul Oh) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11

In this research, the improvement of torque steer is proposed by studying of torque steer mechanism. First, torque steer mechanism is investigated by measuring for torque steer phenomena and the basic cause. And we have derived improvement through correlation between test results and simulation, and then checked up the improvement in a vehicle. Finally, torque steer development standard for high performance engine vehicle is established.

SYMMER: A Systematic Approach to Multiple Musical Emotion Recognition

Jaesung Lee,Jin-Hyuk Jo,Jae-Joon Lee,Daewon Kim 한국지능시스템학회 2011 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.11 No.2

Music emotion recognition is currently one of the most attractive research areas in music information retrieval. In order to use emotion as clues when searching for a particular music, several music based emotion recognizing systems are fundamentally utilized. In order to maximize user satisfaction, the recognition accuracy is very important. In this paper, we develop a new music emotion recognition system, which employs a multilabel feature selector and multilabel classifier. The performance of the proposed system is demonstrated using novel musical emotion data.

SECURITY AGENCY: Differences in Leaders Followership in the Korean Security Police Organization according to the Educational Background and Employment Paths

Jaesung Nam,Hoyeun Youn,Sunggu Jo J-INSTITUTE 2020 International Journal of Terrorism & National Secu Vol.5 No.2

Purpose: In this study, police officers of the security police organization, which is the backbone of the security of the Republic of Korea, will be analyzed for their perception of the leaders followership and will seek policy measures to improve the positive leadership of the security police organization, the subsequent followership, and even the positive self-leadership of the members of the organization. Method: In this study, 100 police officers in the security department of the Korean police organization were surveyed using self-administration method to analyze the perceived attitude toward leaders followership. Edu-cational background and employment paths were used as the main variables for measurement. Among the var-ious characteristics of the special security police, the focus was on how the leaders followership differed accord-ing to the educational background and employment paths of the security police department. Results: According to the analysis, for most of the questions that showed statistical significance, security po-lice officers with a relatively high level of education rated the leaders followership higher. For employment paths, on most of the questions that showed statistical significance, security police officers who were police cadets were found to have a more positive assessment of the leaders followership than those who became police officers through general recruitment or special recruitment. Conclusion: In order to ensure that security police officers with a relatively low level of education and who were general policemen/women are reborn as more voluntary and active model followers, the overall employ-ment paths of the entire police organization, including the security police, need to improve. That police officers with a relatively low level of education and who were general policemen/women had a negative assessment of the leaders followership may be a negative reaction to the problems that the security police organization has been constantly undergoing changes depending on the government s political orientation. Therefore, future gov-ernment, political circles, and police leaders should not make drastic changes to the security police organization in line with the government s political orientation and the micro changes in the inter-Korean relations.

Determination of the PDE-5 Inhibitors and Their Analogues by GC-MS and TMS Derivatization

Jaesung Pyo,Heesang Lee,Yujin Park,Jiyeong Jo,Yonghoon Park,Sanggil Choe,Miyoung Lee,Jaesin Lee 사단법인 한국질량분석학회 2012 Mass spectrometry letters Vol.3 No.1

Eighteen of the PDE-5 inhibitors and their analogues were analyzed using GC-EI-MS. Fourteen of them could beidentified by simple GC-MS method without derivatization, but hydroxyhongdenafil, hydroxyvardenafil, xanthoanthrafil andmirodenafil could not be identified without derivatization for the high polarity due to the presence of hydroxyl groups. N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide (MTBSTFA), widely used trimethylsilyl (TMS) derivatizing reagents, were used to improve the sensitivity of the hydroxylated analogues. And the analytes could be identified by GC-MS after the derivatization. Eighteen of the PDE-5 inhibitors and their analogues were analyzed using GC-EI-MS. Fourteen of them could beidentified by simple GC-MS method without derivatization, but hydroxyhongdenafil, hydroxyvardenafil, xanthoanthrafil andmirodenafil could not be identified without derivatization for the high polarity due to the presence of hydroxyl groups. N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide (MTBSTFA), widely used trimethylsilyl(TMS) derivatizing reagents, were used to improve the sensitivity of the hydroxylated analogues. And the analytes couldbe identified by GC-MS after the derivatization.

Reducing lesion incidence in pork carcasses by heating foot-and-mouth disease vaccine before injection

Cho, Jaesung,Ko, Eun Young,Jo, Kyung,Lee, Seonmin,Jang, Sungbong,Song, Minho,Jung, Samooel Asian Australasian Association of Animal Productio 2020 Animal Bioscience Vol.33 No.4

Objective: This study was conducted to investigate the effect of heating of foot-and-mouth disease (FMD) vaccine before injection, on the incidence of lesions at the injection site (pork butt), amount of discarded meat, and economical benefit. Methods: In total, 101,086 piglets raised in 30 farms, were vaccinated in the neck with 2 mL of FMD vaccine at 56 d and 84 d of age using a commercial syringe. The heat treatment group (48,511 pigs) was injected with the FMD vaccine after it had been heated in a water bath at 40℃ for 20 min. After slaughter, the incidence of lesions on the pork butt was inspected, and the subsequent amount of discarded meat was recorded. Results: Heat treatment of FMD vaccine reduced the incident rate of lesions on the pork butt (p<0.01). Overall, 17.81% of the pigs in the heat treatment group had lesions, while the incident rate in the control group was 21.70%. The amount of discarded meat per head of total pigs and per head of pigs with lesions were significantly lower in the heat treatment group than the control group (p<0.01). Thus, the proportion of discarded meat to dressed carcass was lower in the heat treatment group (0.249%) compared with the control group (0.338%) (p<0.01). Farms that rear 1,000 sows can gain 1,863,289 KRW (1,600 USD) in one year when they adopt heat treatment of FMD vaccine before injection. Conclusion: Heat treatment of FMD vaccine using simple heat equipment (water bath) can be effective in reducing lesions caused by FMD vaccination and increase the economic benefits in pig farms.