• 정보보호학회논문지
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• 제31권3호
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• pp.481-496
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• 2021

대규모 양자컴퓨팅 기술의 실현을 앞둔 현재 공개키 암호 시스템을 양자내성을 가진 암호 시스템으로 전환하는 것은 필수적이다. 미국 국립표준기술연구소 NIST는 양자내성암호(Post-Quantum Cryptography, PQC)를 표준화하기 위한 공모사업을 추진하고 있으며 인터넷 통신 보안에 주로 사용되는 TLS(Transport Layer Security) 프로토콜에 이러한 양자내성암호를 적용하기 위한 차원의 연구도 활발히 진행되고 있다. 본 논문에서는 병렬화된 양자내성암호 NTRU를 활용하여 TLS 상에서 서버와 다수의 사용자가 세션키를 공유하기 위한 키 교환(key exchange) 시나리오를 제시한다. 또한, GPU를 이용하여 NTRU를 병렬화 및 연산을 고속화하는 방법을 제시하고 서버가 대규모 데이터를 처리해야 하는 환경에서 그 효율성을 분석한다.

• 센서학회지
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• 제33권4호
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• pp.224-229
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• 2024

Quantum dot light-emitting diodes (QD-LEDs) are emerging as next-generation displays owing to their high color purity, wide color gamut, and solution processability. Enhancing the efficiency of QD-LEDs involves preventing non-radiative recombination mechanisms, such as Auger and interfacial recombination. Generally, ZnO serves as the electron transport layer, which is known for its higher mobility compared to that of organic semiconductors and can lead to excessive electron injection. Some of the injected electrons pass through the quantum dot emissive layer and undergo non-radiative recombination near or within the organic hole transport layer (HTL), resulting in HTL degradation. Therefore, the implementation of electron blocking layers (EBLs) is essential; however, studies on all-solution-processed inverted InP QD-LEDs are limited. In this study, poly(9-vinylcarbazole) (PVK) is introduced as an EBL to mitigate HTL degradation and enhance the emission efficiency of inverted InP QD-LEDs. Using a single-carrier device, PVK was confirmed to effectively inhibit electron overflow into the HTL, even at extremely low thicknesses. The optimization of the PVK thickness also ensured minimal disruption of the hole-injection properties. Consequently, a 1.5-fold increase in the maximum luminance was achieved in the all-solution-processed inverted InP QD-LEDs with the EBL.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.240.2-240.2
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• 2013

The device scale of flash memory was confronted with quantum mechanical limitation. The next generation memory device will be required a break-through for the device scaling problem. Especially, graphene is one of important materials to overcome scaling and operation problem for the memory device, because ofthe high carrier mobility, the mechanicalflexibility, the one atomic layer thick and versatile chemistry. We demonstrate the hybrid memory consisted with the metal-oxide quantum dots and the mono-layered graphene which was transferred to $SiO_2$ (5 nm)/Si substrate. The 5-nm thick secondary $SiO_2$ layer was deposited on the mono-layered graphene by using ultra-high vacuum sputtering system which base pressure is about $1{\times}10^{-10}$ Torr. The $In_2O_3$ quantum dots were distributed on the secondary $SiO_2$2 layer after chemical reaction between deposited In layer and polyamic acid layer through soft baking at $125^{\circ}C$ for 30 min and curing process at $400^{\circ}C$ for 1 hr by using the furnace in $N_2$ ambient. The memory devices with the $In_2O_3$ quantum dots on graphene monolayer between $SiO_2$ thin films have demonstrated and evaluated for the application of next generation nonvolatile memory device. We will discuss the electrical properties to understating memory effect related with quantum mechanical transport between the $In_2O_3$ quantum dots and the Fermi level of graphene layer.

• Journal of Korean Society for Atmospheric Environment
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• 제22권E2호
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• pp.89-98
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• 2006

Two tobacco cultivars (Nicotiana tabacum L.), Bel-B and Bel-W3, tolerant and sensitive to ozone, respectively, were grown in a greenhouse supplied with charcoal filtered air and exposed to 200 ppb ozone for 4 hr. Effects on chlorophyll fluorescence, net photosynthesis, and stomatal conductance are described. Quantum yield was calculated from chlorophyll fluorescence and the initial slope of the assimilation-light curve measured by the gas exchange method. Only the sensitive cultivar, Bel-W3, developed visual injury symptoms on up to 50% of the $5^{th}$ leaf. The maximum net photosynthetic rate of ozone-treated plants was reduced 40% compared to control plants immediately after ozone fumigation in the tolerant cultivar; however, photosynthesis recovered by 24 hr post fumigation and remained at the same level as control plants. On the other hand, ozone exposure reduced maximum net photosynthesis up to 50%, with no recovery, in the sensitive cultivar apparently causing permanent damage to the photosystem. Reductions in apparent quantum efficiency, calculated from the assimilation-light curve, differed between cultivars. Bel-B showed an immediate depression of 14% compared to controls, whereas, Bel-W3 showed a 27% decline. Electron transport rate (ETR), at saturating light intensity, decreased 58% and 80% immediately after ozone treatment in Bel-B and Bel-W3, respectively. Quantum yield decreased 28% and 36% in Bel-B and Bel-W3, respectively. It can be concluded that ozone caused a greater relative decrease in linear electron transport than maximum net photosynthesis, suggesting greater damage to PSII than the carbon reduction cycle.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.146-146
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• 2015

We report the enhanced performance of poly(N-vinylcarbozole) (PVK)/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)-based quantum-dot light-emitting diodes by inserting the polyaniline:poly (p-styrenesulfonic acid) (PANI:PSS) interlayer. The QD-LED with PANI:PSS interlayer exhibited a higher luminance and luminous current efficiency than that without PANI:PSS. Ultraviolet photoelectron spectroscopy results exhibited different electronic energy alignments of QD-LEDs with/without the PANI:PSS interlayer. By inserting the PANI:PSS interlayer, the hole-injection barrier at the QD layer/PVK interface was reduced from 1.45 to 1.23 eV via the energy level down-shift of the PVK layer. The reduced barrier height alleviated the interface carrier charging responsible for the deterioration of the current and luminance efficiency. This suggests that the insertion of PANI:PSS interlayer in QD-LEDs contributed to (i) increase the p-type conductivity and (ii) reduce the hole barrier height of QDs/PVK, which are critical factors leading to improve the efficiency of QD-LEDs.

• 한국진공학회지
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• 제10권2호
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• pp.262-266
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• 2001

GaAS/AlGaAS 이종접합구조 위에 Split gate로 양자세선을 제작하여 Shubnikov de Haas 진동 및 양자 Hall 효과 측정으로 1DEG의 전기적 특성을 관측하였다. Gate 전압이 증가할수록 채널폭이 좁아짐에 따라 ID 특성이 나타났다. Edge state 수송 이론인 Landauer-Butikker formula로부터 QHE plateau와 SdH 진동의 최소값이 나타나는 자기장 영역이 일치하지 않고 있는 현상을 명확히 규명하였다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제6권1호
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• pp.1-9
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• 2006

We introduce our in-house program, NANOCAD, for the modeling and simulation of carrier transport in nanoscale MOSFET devices including quantum-mechanical effects, which implements two kinds of modeling approaches: the top-down approach based on the macroscopic quantum correction model and the bottom-up approach based on the microscopic non-equilibrium Green’s function formalism. We briefly review these two approaches and show their applications to the nanoscale bulk MOSFET device and silicon nanowire transistor, respectively.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.319.1-319.1
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• 2014

We present the results on the indium tin oxide (ITO) Schottky barrier solar cells (SBSCs) with InAs quantum dots (QDs). The dependence of external quantum efficiency on the external bias voltage has been studied to anlayze carrier extraction through tunneling at room temperature.

• 한국전기전자재료학회논문지
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• 제14권12호
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• pp.1027-1031
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• 2001

A new constant growth technique to conserve an initial grating height of V-groove AlGaAs/InGaAs quantum nanostructures above 1.0 $\mu\textrm{m}$ thickness has been successfully embodied on submicron gratings using low pressure metalorganic chemical vapor deposition. A GaAs buffer prior to an AlGaAs barrier layer on submicron gratings plays an important role in overcoming mass transport effects and improving the uniformity of gratings. Transmission electron microscopy (TEM) image shows that high-density V-groove InGaAs quantum wires (QWRs) are well confined at the bottom of gratings. The photoluminescence (PL) peak of the InGaAs QWRs is observed in the temperature range from 10 to 280 K with a relatively narrow full width at half maximum less than 40 meV at room temperature PL. The constant growth technique is an important step to realize complex optoelectronic devices such as one-step grown distributed feedback lasers and two-dimensional photonic crystal.

• Nuclear Engineering and Technology
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• 제47권3호
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• pp.293-305
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• 2015

In this paper, we suggest the conceptual design of a water-cooled reactor system for a low-pressure inherent heat sink nuclear desalination plant (LIND) that applies the safety-related design concepts of high temperature gas-cooled reactors to a water-cooled reactor for inherent and passive safety features. Through a scoping analysis, we found that the current LIND design satisfied several essential thermal-hydraulic and neutronic design requirements. In a thermal-hydraulic analysis using an analytical method based on the Wooton-Epstein correlation, we checked the possibility of safely removing decay heat through the steel containment even if all the active safety systems failed. In a neutronic analysis using the Monte Carlo N-particle transport code, we estimated a cycle length of approximately 6 years under 200 $MW_{th}$ and 4.5% enrichment. The very long cycle length and simple safety features minimize the burdens from the operation, maintenance, and spent-fuel management, with a positive impact on the economic feasibility. Finally, because a nuclear reactor should not be directly coupled to a desalination system to prevent the leakage of radioactive material into the desalinated water, three types of intermediate systems were studied: a steam producing system, a hot water system, and an organic Rankine cycle system.