• 한국초전도ㆍ저온공학회논문지
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• 제8권4호
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• pp.8-11
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• 2006

High temperature superconducting coated conductor has various buffer structures on Ni-W alloy. We comparatively studied the growth conditions of a multi buffer layer $(CeO_2/YSZ/CeO_2)$ and a single buffer layer$(CeO_2)$ on textured Ni-W alloy tapes. XRD data showed that the qualities of in-plane and out-of-plane textures of the two type buffer structures were good. Also, we investigated the properties of SmBCO superconducting layer that was deposited on the two type buffer structure. The SmBCO superconducting properties on the single and multi buffer structure showed different critical current values and surface morphologies. FWHM of In-plane and out-of-plane textures were $7.4^{\circ},\;5.0^{\circ}$ in the top CeO2 layer of the multi-buffer layers of $CeO_2/YSZ/CeO_2$, and $7.3^{\circ},\;5.1^{\circ}$ in the $CeO_2$ single buffer layer. $1{\mu}m-thick$ SmBCO superconducting layers were deposited on two type buffer layer. $I_c$ of SmBCO deposited on single and multi buffer were 90 A/cm, 150 A/cm and corresponding $J_c$ were $0.9MA/cm^2,\;1.5MA/cm^2$ at 77K in self-field, respectively.

• 한국자기학회지
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• 제16권6호
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• pp.283-286
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• 2006

고밀도 자기기록용 Ba-페라이트/$SiO_{2}$ 자성박막에서 계면확산 장벽으로써 ${\alpha}-Al_{2}O_{3}$ 버퍼층의 역할을 연구하였다. 열처리동안 $1900{\AA}$의 두께를 가진 비정질 Ba-페라이트/$SiO_{2}$ 박막에서 계면확산은 약 $700^{\circ}C$에서 일어나기 시작하였다. 열처리온도를 $800^{\circ}C$까지 증가시켰을 때, 계면확산은 자기특성을 저하시킬 정도로 급격히 진행되었다. 고온에서의 계면확산을 억제하기 위하여, $110{\AA}$ 두께의 ${\alpha}-Al_{2}O_{3}$ 버퍼층을 Ba-페라이트/$SiO_{2}$ 박막의 계면에 증착하여 사용하였다. Ba-페라이트/${\alpha}-Al_{2}O_{3}/SiO_{2}$ 박막에서는 $800^{\circ}C$의 고온까지 열처리하여도 계면확산이 심각하게 일어나지는 않았다. ${\alpha}-Al_{2}O_{3}$ 버퍼층에 의하여 계면확산이 억제되기 때문에 Ba-페라이트 자성박막의 포화자속밀도와 보자력이 향상되었다. 따라서 Ba-페라이트/$SiO_{2}$ 박막의 계면에서 ${\alpha}-Al_{2}O_{3}$ 버퍼층은 $SiO_{2}$ 기판 성분의 계면확산 장벽으로 사용될 수 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 C
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• pp.873-875
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• 1999

We have fabricated good quality superconducting $YBa_{2}Cu_{3}O_{7-\delta}$ thin films on Hastelloy(Ni-Cr-Mo alloys) metallic substrate with $CeO_2$ and $BaTiO_3$ buffer layers in-situ by pulsed laser deposition in a multi-target processing chamber. We have chosen $CeO_2$ as a buffer layer which has cubic structure of $5.41{\AA}$ lattice parameter and only 0.2% of lattice mismatch with YBCO. $CeO_2$ layer may be helpful for power transmission due to its conducting property. In order to enhance the crystallization of YBCO films on metallic substrates. we deposited $CeO_2$ and $BaTiO_3$ buffer layers at various temperatures. The YBCO superconducting tape fabricated with $BaTiO_3$ and $CeO_2$ buffer layers shows 85K of transition temperature and about $8.4{\times}10^4A/cm^2$ of critical current density at 77K.

• 한국진공학회지
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• 제17권6호
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• pp.560-565
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• 2008

본 연구에서는 PLZT 박막이 $(Pb_{0.92}La_{0.08})(Zr_{0.65}Ti_{0.35})O_3$ 조성의 타겟을 이용한 R.F. 마그네트론 스퍼터링공정에 의해 실리콘 웨이퍼 위에 증착되었다. PLZT 박막의 강유전특성을 향상시키기 위해 buffer layer인 $TiO_2$ 층이 사용되었으며, buffer layer의 후열처리온도 변화에 따른 PLZT 박막의 결정성과 유전특성이 연구되었다. buffer layer이 삽입되지 않은 PLZT 박막의 잔류분극값은 $19.13{\mu}C/cm^2$ 이었으며, 반면 $TiO_2$ buffer layer을 삽인한 후 후열처리 온도를 $600^{\circ}C$로 증가시킨 PLZT 박막의 잔류분극값은 $146.62{\mu}C/cm^2$까지 크게 증가하였다. 하부전극 백금(Pt)과 PLZT 박막층 사이에 삽입된 $TiO_2$ buffer layer의 특성과 PLZT 박막의 유전특성에 미치는 영향을 살펴보기 위해 글로우 방전 분광법 (glow discharge spectroscopy, GDS)이 PLZT 박막(PLZT/($TiO_2$)/Pt/Ti/$SiO_2$/Si wafer)에 대해 수행 되었다.

• 한국초전도ㆍ저온공학회논문지
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• 제13권1호
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• pp.6-11
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• 2011

The $BaHfO_3$ (BHO) buffer layer on the IBAD MgO template was turned to be effective for a successful fabrication of $GdBa_2Cu_3O_{7-{\delta}}$ (GdBCO) films with high critical current density ($J_c$). Both the BHO buffer layers and GdBCO films were prepared by pulsed laser deposition (PLD). The effects of the PLD conditions, including substrate temperature ($T_s$), oxygen partial pressure ($PO_2$), and deposition time on the in-plane texture, surface roughness, and microstructures of the BHO buffer layers on the IBAD MgO template were systematically studied for processing optimization. The c-axis oriented growth of BHO layers was insensitive to the deposition temperature and the film thickness, while the in-plane texture and surface roughness of those were improved with increasing $T_s$ from 700 to $800^{\circ}C$. On the optimally processed BHO buffer layer, the highest $J_c$ value (77 K, self-field) of 3.68 $MA/cm^2$ could be obtained from GdBCO film deposited at $780^{\circ}C$, representing that BHO is a strong candidate for the buffer layer on the IBAD MgO template.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2007년도 추계학술발표대회 및
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• pp.46.1-46.1
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• 2007

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 1999년도 High Temperature Superconductivity Vol.IX
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• pp.392-396
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• 1999

Superconducting YBa$_2Cu_3O_{7-{\delta}}$(YBCO) thin films were grown on Hastelloy(Ni-Cr-Mo alloys) with CeO$_2$ buffer layer in-situ by pulsed laser deposition in a multi-target processing chamber. To apply superconducting property on power transmission line, we have deposited YBCO thin film on flexible metallic substrate. However, it is difficult to grow the YBCO films on flexible metallic substrates due to both interdiffusion problem between metallic substrate and superconducting overlayers and non-crystallization of YBCO on amorphous substrate. It is necessary to use a buffer layer to overcome the difficulties. We have chosen CeO$_2$ as a buffer layer which has cubic structure of 5.41 ${\AA}$ lattice parameter and only 0.2% of lattice mismatch with 3.82 ${\AA}$ of a-axis lattice parameter of YBCO on [110] direction of CeO$_2$ In order to enhance the crystallization of YBCO films on metallic substrates, we deposited CeO$_2$ buffer layers with varying temperature and 02 pressure. By XRD, it is observed that dominated film orientation is strongly depending on the deposition temperature of CeO$_2$ layer. The dominated orientation of CeO$_2$ buffer layer is changed from (200) to(111) by increasing the deposition temperature and this transition affects the crystallization of YBCO superconducting film on CeO$_2$ buffered Hastelloy.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1646-1648
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• 2000

This paper investigated structural and electrical properties of $Y_{2}O_3$ as a buffer layer of sin91r transistor FRAM (ferroelectric RAM). $Y_{2}O_3$ buffer layers were deposited at a low substrate temperature below 400$^{\circ}C$ and then RTA (rapid thermal anneal) treated. Investigated parameters are substrate temperature, $O_2$ partial pressure, post- annealing temperature, and suppression of interfacial $SiO_2$ layer generation. for a well-fabricated sample, we achieved that leakage current density ($J_{leak}$) in the order of $10^{-7}A/cm2$, breakdown electric field ($E_{br}$) about 2 MV/cm for $Y_{2}O_3$ film. Capacitance versus voltage analysis illustrated dielectric constants of 7.47. We successfully achieved an interface state density of $Y_{2}O_3$/Si as low as $8.72{\times}10^{10}cm^{-2}eV^{-1}$. The low interface states were obtained from very low lattice mismatch less than 1.75%.

• Korean Chemical Engineering Research
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• 제55권1호
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• pp.93-98
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• 2017

본 실험에서는 $Cu_2ZnSnS_4$(CZTS) 태양전지의 흡수층 상부에 다양한 조성을 갖는 $Zn(O_x,S_{1-x})$ 버퍼층을 적용하여 특성 변화를 살펴보았다. $Zn(O_{0.76},S_{0.24})$, $Zn(O_{0.56},S_{0.44})$, $Zn(O_{0.33},S_{0.67})$ 그리고 $Zn(O_{0.17},S_{0.83})$의 4가지 단일막의 경우, 전자-정공의 재결합 억제에 유리한 밴드갭 구조를 나타내는 $Zn(O_{0.76},S_{0.24})$ 버퍼층을 소자에 적용했다. $Zn(O_{0.76},S_{0.24})$ 버퍼층을 소자에 적용 시, 흡수층으로부터 S가 버퍼층으로 확산되어 소자 내에서의 버퍼층은 $Zn(O_{0.7},S_{0.3})$의 조성을 나타냈다. CdS 버퍼층의 $E_V$보다 낮은 에너지 준위를 갖는 $Zn(O_{0.7},S_{0.3})$ 버퍼층은 전자-정공 재결합을 효과적으로 억제하기 때문에 CZTS 태양전지의 $J_{SC}$와 $V_{OC}$ 특성을 향상시켰다. 이를 통해 CdS 버퍼층이 적용된 CZTS 태양전지의 효율인 2.75%가 $Zn(O_{0.7},S_{0.3})$ 버퍼층 적용을 통해 4.86%로 향상되었다.

• Current Photovoltaic Research
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• 제3권2호
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• pp.54-60
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• 2015

ZnSnO thin films were deposited by atomic layer deposition (ALD) process using diethyl zinc ($Zn(C_2H_5)_2$) and tetrakis (dimethylamino) tin ($Sn(C_2H_6N)_4$) as metal precursors and water vapor as a reactant. ALD process has several advantages over other deposition methods such as precise thickness control, good conformality, and good uniformity for large area. The composition of ZnSnO thin films was controlled by varying the ratio of ZnO and $SnO_2$ ALD cycles. The ALD ZnSnO film was an amorphous state. The band gap of ZnSnO thin films increased as the Sn content increased. The CIGS solar cell using ZnSnO buffer layer showed about 18% energy conversion efficiency. With such a high efficiency with the ALD ZnSnO buffer and no light soaking effect, AlD ZnSnO buffer mighty be a good candidate to replace Zn(S,O) buffer in CIGSsolar cells.