• Electrical & Electronic Materials
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• v.10 no.10
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• pp.1034-1040
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• 1997

A solar cell conversion effiency was degraded by grain boundary effect in polycrystalline silicon. Grain boundaries acted as potential barriers as well as recombination centers for the photo-generated carriers. To reduce these effects of the grain boundaries we investigated various influencing factors such as emitter thickness thermal treatment preferential chemical etching of grain boundaries grid design contact metal and top metallization along boundaries. Pretreatment in $N_2$atmosphere and gettering by POCl$_3$and Al were performed to obtain multicrystalline silicon of the reduced defect density. Structural electrical and optical properties of slar cells were characterized before and after each fabrication process. Improved conversion efficiencies of solar cell were obtained by a combination of pretreatment above 90$0^{\circ}C$ emitter layer of 0.43${\mu}{\textrm}{m}$ Al diffusion in to grain boundaries on rear side fine grid finger top Yb metal and buried contact metallization along grain boundaries.

• JSTS:Journal of Semiconductor Technology and Science
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• v.6 no.3
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• pp.125-130
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• 2006

The optical gain and the luminescence of a ZnO quantum well with MgZnO barriers is studied theoretically. We calculated the non-Markovian optical gain and the luminescence for the strained-layer wurtzite quantum well taking into account of the excitonic effects. It is predicted that both optical gain and luminescence are enhanced for the ZnO quantum well when compared with those of InGaN-AlGaN quantum well structure due to the significant reduction of the piezoelectric effects in the ZnO-MgZnO systems.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.8
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• pp.62-71
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• 1994

A novel semiconductor device is proposed to be used as a processing element for the implementation of pulse-mode neural networks which consists of alternating n' GaAs quantum wells and undoped AlGaAs barriers sandwitched between n' GaAs cathode and P' GaAs anode and in simple circuit in conjunction with a parallel capacitive and resistive load the trigger circuit generates neuron-like pulse train output mimicking the function of axon hillock of biological neuron. It showed the sigmoidal relationship between the frequency of the pulse-train and the applied input DC voltage. In conjunction with MQWIMD the various neural circuits are proposed especially a neural chip monolithically integrated with photodetectors in order to perfrom the pattern recognition.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.186-186
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• 2010

소자의 축소화에 따라 floating gate 형의 flash 메모리 소자는 얇은 게이트 절연막 등의 이유로, 이웃 셀 간의 커플링 및 게이트 누설 전류와 같은 문제점을 지니고 있다. 이러한 문제점을 극복하기 위해 charge trap flash 메모리 (CTF) 소자가 연구되고 있지만, CTF 메모리 소자는 쓰기/지우기 속도와 데이터 보존 성능간의 trade-off 관계와 같은 문제점을 지니고 있다. 최근, 이를 극복하기 위한 방안으로, 다른 유전율을 갖는 유전체들을 적층시킨 터널 절연막을 이용한 Tunnel Barrier Engineered (TBE) 기술이 주목 받고 있다. 따라서, 본 논문에서는 TBE 기술을 적용한 MIS-capacitor를 높은 유전율을 가지는 Al2O3와 HfO2를 이용하여 제작하였다. 이를 위해 먼저 Si 기판 위에 Al2O3 /HfO2 /Al2O3 (AHA)를 Atomic Layer Deposition (ALD) 방법으로 약 2/1/3 nm의 두께를 가지도록 증착 하였고, Aluminum을 150 nm 증착 하여 게이트 전극으로 이용하였다. Capacitance-Voltage와 Current-Voltage 특성을 측정, 분석함으로써, AHA 구조를 가지는 터널 절연막의 전기적인 특성을 확인 하였다. 또한, high-k 물질을 이용한 터널 절연막을 급속 열처리 공정 (Rapid Thermal Annealing-RTA) 과 H2/N2분위기에서 후속열처리 공정 (Post-RTA)을 통하여 전기적인 특성을 개선 시켰다. 적층된 터널 절연막은 열처리를 통해 터널링 전류의 민감도의 향상과 함께 누설전류가 감소됨으로서 우수한 전기적인 특성이 나타남을 확인하였으며, 적층된 터널 절연막 구조와 적절한 열처리를 이용하여 빠른 쓰기/지우기 속도와 전기적인 특성이 향상된 비휘발성 메모리 소자를 기대할 수 있다.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.7
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• pp.3483-3487
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• 2016

Background: Cigarette smoking is one of the leading causes of death in the world. Tobacco consumption has grave negative consequences for health so that it is important to understand the reasons and motivations towards cigarette smoking and barriers against quitting smoking among the young generation for developing effective policies to control this widespread problem. Materials and Methods: This cross-sectional survey was carried out at the Faculty of Medicine, Rabigh, King Abdulaziz University, Jeddah, Saudi Arabia. A total of 438 young smokers participated from the University and the general population. Data were collected through anonymous, self-administered questionnaires in the Arabic language that contained questions about the reasons and motivations towards cigarette smoking and barriers against quitting smoking. The questionnaire also contained several questions regarding knowledge and attitude of the participants towards cigarette smoking. The data was analyzed on SPSS-16. Results: The mean age of the respondents was $22.9{\pm}3.48$, out of 438 subjects 87 (19.9%) were married, and 351 (80.1%) were unmarried, and 331 (75.6%) belonged to urban areas while 107 (24.5%) were from the rural areas. Responding to a question about a number of cigarettes smoked per day, 31% answered 11-20, 29% answered 21-30, and 25% answered 1-10. Questioned about smokers in the family, 34.5% responded more than one, with 19% for brother and 13% for father. About the reasons for not quitting smoking, 26% described lack of willpower, 25% had no reason, 22% said that people around me smoke, and 15.3% responded stress at home/work. The major motivation for smokers was smoker friends (42%), for 33.8% others, for 12% father/brother and 7.8% media. Conclusions: There are several avoidable and preventable reasons and barriers against quitting smoking. However, knowledge and attitude about smoking were good, and the majority of the smokers were well aware of the associated hazards. Therefore, there is a need to search out ways and means to help them to quit this addiction.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.8
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• pp.735-746
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• 2020

This research is defined as a study regarding on structured and systematized of existing literature review of the intersection between intellectual property management, management and technology transfer offices (TTOs). It takes a deeper look at requirements within universities, scientific institutions and the business environment should be interconnected with each other. The literature review shows that TTOs have control over the process of knowledge transfer and they have contributed to improving the efficiency of the use of production and human resources. In this paper, authors proposed the methodological tools based on methodology model, which identified success factors for using project management in TTO between two countries - Kazakhstan and Spain. Further, we used methodology is focused on solving the problems of quantitative analysis based on the use of primary data, which allowed us to reach a huge number of respondents without any restrictions, and secondary data from statistical database. Findings and results are summarized at the end of article show that Kazakhstan is following the path of the Spanish experience. However, Kazakhstan can become more successful in commercializing scientific technologies and transferring knowledge and technologies. In turn, Spain can use the data from our analysis to work on barriers and improve the activities of TTOs.

• Journal of the Semiconductor & Display Technology
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• v.22 no.4
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• pp.103-107
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• 2023

To solve the reliability problem of organic devices that are often used outdoors, multifunctional gas barriers that block reactive gases such as moisture and oxygen and reflect harmful light such as ultraviolet rays are needed. In this study, ALD nanolaminate-based optically functional n-DBR was developed to overcome the poor gas permeability of polymer substrates and protect organic devices from harmful light. n-DBR not only achieved a WVTR of 8.76 × 10^-6 g·m^-2·day^-1, but also showed a visible light transmittance of 94.3% and an ultraviolet ray blocking ability of 2.67%. In particular, n-DBR based on a nanolaminate structure maintained its permeability characteristics even in a high temperature and high humidity environment despite being used as a layer of Al₂O₃. This functional barrier Structure can not only be used as a functional encapsulation barrier for the reliability of organic devices, but can also be used as a tinting film for vehicles.

• Solar Energy
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• v.17 no.4
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• pp.3-11
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• 1997

Because grain boundaries in polycrystalline silicon act as potential barriers and recombination centers for the photo-generated charge carriers, these defects degrade conversion effiency of solar cell. To reduce these effects of grain boundaries, we investigated various influencing factors such as thermal treatment, various grid pattern, selective wet etching for grain boundaries, buried contact metallization along grain boundaries, grid on metallic thin film. Pretreatment above $900^{\circ}C$ in $N_2$ atmosphere, gettering by $POCl_3$ and Al treatment for back surface field contributed to obtain a high quality poly-Si. To prevent carrier losses at the grain boundaries, we carried out surface treatment using Schimmel etchant. This etchant delineated grain boundaries of $10{\mu}m$ depth as well as surface texturing effect. A metal AI diffusion into grain boundaries on rear side reduced back surface recombination effects at grain boundaries. A combination of fine grid with finger spacing of 0.4mm and buried electrode along grain boundaries improved short circuit current density of solar cell. A ultra-thin Chromium layer of 20nm with transmittance of 80% reduced series resistance. This paper focused on the grain boundary effect for terrestrial applications of solar cells with low cost, large area, and high efficiency.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.133-133
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• 2008

Recently, as the down-scailing of field-effect transistor devices continues, Schottky-barrier field-effect transistors (SB-FETs) have attracted much attention as an alternative to conventional MOSFETs. SB-FETs have advantages over conventional devices, such as low parasitic source/drain resistance due to their metallic characteristics, low temperature processing for source/drain formation and physical scalability to the sub-10nm regime. The good scalability of SB-FETs is due to their metallic characteristics of source/drain, which leads to the low resistance and the atomically abrupt junctions at metal (silicide)-silicon interface. Nevertheless, some reports show that SB-FETs suffer from short channel effect (SCE) that would cause severe problems in the sub 20nm regime.[Ouyang et al. IEEE Trans. Electron Devices 53, 8, 1732 (2007)] Because source/drain barriers induce a depletion region, it is possible that the barriers are overlapped in short channel SB-FETs. In order to analyze the SCE of SB-FETs, we carried out systematic studies on the Schottky barrier overlapping in short channel SB-FETs using a SILVACO ATLAS numerical simulator. We have investigated the variation of surface channel band profiles depending on the doping, barrier height and the effective channel length using 2D simulation. Because the source/drain depletion regions start to be overlapped each other in the condition of the $L_{ch}$~80nm with $N_D{\sim}1\times10^{18}cm^{-3}$ and $\phi_{Bn}$ $\approx$ 0.6eV, the band profile varies as the decrease of effective channel length $L_{ch}$. With the $L_{ch}$~80nm as a starting point, the built-in potential of source/drain schottky contacts gradually decreases as the decrease of $L_{ch}$, then the conduction and valence band edges are consequently flattened at $L_{ch}$~5nm. These results may allow us to understand the performance related interdependent parameters in nanoscale SB-FETs such as channel length, the barrier height and channel doping.

• Journal of the Korean Magnetics Society
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• v.17 no.3
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• pp.120-123
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• 2007

The typical double-barrier magnetic tunnel junction (DMTJ) structure examined in this paper consists of a Ta 45/Ru 9.5/IrMn 10/CoFe7/$AlO_x$/free layer/AlO/CoFe 7/IrMn 10/Ru 60 (nm). The free layer consists of an $Ni_{16}Fe_{62}Si_8B_{14}$ 7 nm, $Co_{90}Fe_{10}$ (fcc) 7 nm, or CoFe $t_1$/NiFeSiB $t_2$/CoFe $t_1$ layer in which the thicknesses $t_1$ and $t_2$ are varied. The DMTJ with an NiFeSiB-free layer had a tunneling magnetoresistance (TMR) of 28%, an area-resistance product (RA) of $86\;k{\Omega}{\mu}m^2$, a coercivity ($H_c$) of 11 Oe, and an interlayer coupling field ($H_i$) of 20 Oe. To improve the TMR ratio and RA, a DMTJ comprising an amorphous NiFeSiB layer that could partially substitute for the CoFe free layer was investigated. This hybrid DMTJ had a TMR of 30%, an RA of $68\;k{\Omega}{\mu}m^2$, and a of 11 Oe, but an increased of 37 Oe. We confirmed by atomic force microscopy and transmission electron microscopy that increased as the thickness of NiFeSiB decreased. When the amorphous NiFeSiB layer was thick, it was effective in retarding the columnar growth which usually induces a wavy interface. However, if the NiFeSiB layer was thin, the roughness was increased and became large because of the magnetostatic $N{\acute{e}}el$ coupling.