• 한국진공학회지
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• 제10권3호
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• pp.374-379
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• 2001

MBE를 이용하여 GaAs위에 InAs 양자점을 성장시키고 Ga, As, In, As의 순서로 셔터를 교대로 열어주는 방식으로 3주기 반복하여 InGaAs 층을 성장시키고 그 위에 다시 GaAs층을 성장시킨 시료(시료번호: QDl)에 대하여 온도를 변화시키며 열처리를 수행한 후 그 광학적 특성을 분석하였다. 기존의 다른 그룹들의 연구결과처럼, InAs 양자점을 성장시키고 GaAs 에피층을 barrier층으로 성장시킨 경우, 열처리 온도가 증가함에 따라 발광피크는 단파장쪽으로 이동하는 것을 확인하였다. 반면에, InGaAs층을 포함하고 있는 QDI 시료의 경우, 발광 피크의 위치가 열처리 온도가 $600^{\circ}C$가 될 때까지는 장파장 쪽으로 이동하다가, 그 이상의 온도에서는 단파장 쪽으로 이동하는 현상을 관찰하였다. 또한, 발광피크의 반치폭도 열처리 온도가 증가하면서 감소하는 경향을 보이다가 다시 증가되는 경향을 보이고 있다.

• 한국초전도ㆍ저온공학회논문지
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• 제21권3호
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• pp.13-17
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• 2019

We investigate the effect of thermal annealing on $MgB_2$ thin films with thicknesses of 400 and 800 nm, irradiated by 350 keV C-ions with a dose of $1{\times}10^{15}atoms/cm^2$. Irradiation by low-energy C-ions produces atomic lattice displacement in $MgB_2$ thin films, improving magnetic field performance of critical current density ($J_c$) while reducing the superconducting transition temperature ($T_c$). Interestingly, the lattice displacement and the $T_c$ are gradually restored to the original values with increasing thermal annealing temperature. In addition, the magnetic field dependence of $J_c$ also returns to that of the pristine state together with the restoration of $T_c$. Because $J_c$(H) is sensitive to the type and density of the disorder, i.e. vortex pinning, the recovery of $J_c$(H) in irradiated $MgB_2$ thin films by thermal annealing indicates that low-energy C-ion irradiation on $MgB_2$ thin films primarily causes lattice displacement. These results provide new insights into the application of low-energy irradiation in strategically engineering critical properties of superconductors.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제51권6호
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• pp.236-239
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• 2002

Si nanocrystallites thin films on P-type (100) Si substrate have been fabricated by pulsed laser deposition using a Nd:YAG laser. After deposition, samples were annealed in several environmental gases ;It the temperature range of 400 to $800^{\circ}C$ Hydrogen passivation was then performed in the forming gas (95 % $N_2$ + 5 % $H_2$) for 1 hr. Strong violet-indigo photoluminescence has been observed at room temperature on nitrogen ambient-annealed Si nanocrystallites. We report the variation of photoluminescence (PL) properties of Si thin films by changing annealing temperatures and by using hydrogen passivation. The results could suggest that the origin of violet-indigo PL should be related to the Quantum size effect of Si nanocrystallite.

• 정보과학회 논문지
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• 제43권7호
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• pp.751-762
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• 2016

본고에서는 양자역학 기반의 기계학습인 양자 기계학습의 현황과 전망을 조망하고자 한다. 양자역학 기반의 양자컴퓨팅이 보여준 혁신적인 계산속도 개선에 힘입어 기계학습 분야에 양자컴퓨팅 알고리즘을 적용하는 연구는 빅데이터 시대의 도래에 따라 최근 집중적인 관심을 받고 있다. 고전적인 기계학습 알고리즘들에 양자컴퓨팅을 접목하여 획기적인 속도개선을 가능하게 하는 알고리즘 연구들과 최초의 상용 양자컴퓨터로 화제가 되고 있는 양자 담금질 알고리즘 등을 중심으로 양자 기계학습의 최신동향과 가능성을 살펴보고자 한다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1998년도 제16회 학술발표회 논문개요집
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• pp.86-86
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• 1998

• 한국진공학회지
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• 제7권s1호
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• pp.197-201
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• 1998

Ge quantum dots in $SiO_2$ thin films were prepared by r.f. magnetron co-sputtering using a Ge, $SiO_2$ composite target. The size of quantum dots was modulated by controlling of substrate temperature during depositing and annealing of samples deposited at certain substrate temperature. A series of work was done on the influence of preparing parameters on the growth of quantum dots, and a discussion on the formation and growth of quantum dots under different preparation parameters is given.

• 한국진공학회지
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• 제11권4호
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• pp.207-211
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• 2002

반도체-유전체 덮개층의 다양한 조합이 I $n_{0.53}$G $a_{0.47}$As/InGaAsP(Q1.25) 양자우물 무질서화에 미치는 영향을 PL(Photoluminescence)을 이용하여 조사하였다. 청색 편이에 대한 문턱 온도는 약 $750^{\circ}C$ 였으며 전반적으로 온도가 올라감에 따라 청색 편이도 점차 증가하였으나 $SiO_2$의 경우에는 온도가 올라감에 따라 포화되는 경향을 보였다. $SiN_{x}$ 가 $SiO_2$보다 더 큰 청색 편이를 야기하였는데 이것은 $SiN_{x}$의 낮은 성장 온도와 관계가 있는 것으로 생각된다. $SiN_{x}$의 경우 P의 확산이, 그리고 $SiO_2$의 경우 Ga의 확산이 청색 편이에 중요한 역할을 하는 것으로 여겨진다.겨진다.

• Journal of the Optical Society of Korea
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• 제20권1호
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• pp.130-134
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• 2016

The influence of Au/Ni-based contact formed on a lightly-doped (7.3×1017cm−3, Zn-doped) InGaAsP layer for electrical compensation of surface plasmon polariton (SPP) propagation under various rapid thermal annealing (RTA) conditions has been studied. The active control of SPP propagation is realized by electrically pumping the InGaAsP multiple quantum wells (MQWs) beneath the metal planar waveguide. The metal planar film acts as the electric contact layer and SPP waveguide, simultaneously. The RTA process can lower the metal-semiconductor electric contact resistance. Nevertheless, it inevitably increases the contact interface morphological roughness, which is detrimental to SPP propagation. Based on this dilemma, in this work we focus on studying the influence of RTA conditions on electrical control of SPPs. The experimental results indicate that there is obvious degradation of electrical pumping compensation for SPP propagation loss in the devices annealed at 400℃ compared to those with no annealing treatment. With increasing annealing duration time, more significant degradation of the active performance is observed even under sufficient current injection. When the annealing temperature is set at 400℃ and the duration time approaches 60s, the SPP propagation is nearly no longer supported as the waveguide surface morphology is severely changed. It seems that eutectic mixture stemming from the RTA process significantly increases the metal film roughness and interferes with the SPP signal propagation.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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• pp.195-197
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• 2002

CdTe quantum dots(QDs) were synthesized in aqueous solution by colloidal method. Photoluminescence(PL) spectra of the synthesized CdTe QDs revealed the intensity of PL peaks was stronger as the condensation time was longer. This result was thought because annealing effect by thermal energy transferred during condensation eliminated defects which act as traps and recombination centers in CdTe particle. PL intensity has stron dependence of Te precursor concentration. It confirmed the ratio of Te ion to Cd ion added during synthesis affected the particle size and size distribution of the CdTe QDs. Finally, the synthesized CdTe QDs were identified to be cubic structured CdTe quantum dots by X-ray diffraction(XRD).

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.106-106
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• 2012

Strategies to facilitate carrier transfer/transport while preserving confined characteristics of isolated nanocrystal quantum dots (NQDs) will be discussed. Specifically, synthesis and characterizations of 1) the fabrication of neat NQD solids (assembled NQD films) with modified surfaces by attaching ligands or by applying physical processes such as heat annealing [J. Phys. Chem. C (2011), 115(3), 607] and 2) coupling NQDs to one-dimensional nanostructures such as single-walled carbon nanotubes (SWNTs) [ACS Nano, (2010) 4(1), 324] will be presented. Further, recent achievement ours of fabricating NQDs assemblies into photovoltaic devices for elucidating transfer mechanism witll be discussed.