• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.07a
• /
• pp.37-40
• /
• 2003

Amorphous $Al_2O_3$ nanotubes have been fabricated by utilizing the ZnO nanowires as template with wet etching method. ZnO nanowires synthesized by thermal evaporation are conformally coated with $Al_2O_3$ by atomic-layer deposition(ALD) method. The $Al_2O_3$-coated ZnO nanowires are of core-shell structure; ZnO core nanowires and $Al_2O_3$ shells. When the $ZnO/Al_2O_3$ core-shell structure is dipped in $H_3PO_4$ solution at $25^{\circ}C$ for a 6 min, the core ZnO materials are completely etched, and only $Al_2O_3$ nanotubes are remained. This nanotube fabrication is technically easier than others, and simply approachable. Transmission electron microscopy shows that the $Al_2O_3$ nanotubes have various thicknesses that can be controlled.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2012.05a
• /
• pp.301-302
• /
• 2012

본 연구에서는 ripple 형태의 ZnO 박막을 역구조 태양전지의 전자 수집층으로 사용하였으며, 원자층 증착법 (Atomic Layer Deposition, ALD)을 이용하여 $TiO_2$ 박막을 ZnO 표면에 증착하였다. $TiO_2$가 ZnO 표면 위에 약 <3nm 정도 두께의 초미세 박막으로 형성되었을 경우 태양전지의 성능이 향상되었다. 특히 Jsc (short-circuit current)와 전환효율 값의 향상을 보였다. 반면 $TiO_2$를 더 두껍게 증착되었을 경우 오히려 태양전지 성능이 떨어지는 결과를 얻었다. 이와 같은 결과 전자를 수집하는 ZnO 위에서 $TiO_2$가 장벽으로 작용함으로써 전자의 이동을 억제하기 때문으로 풀이된다. 반면 $TiO_2$가 초미세 박막으로 형성되었을 때 ZnO 표면에 존재하는 결함자리, 즉 전자와 정공이 재결합하는 자리를 덮어줌으로써 오히려 태양전지의 성능을 향상시키게 된다. 본 연구에서는 ALD 방법을 이용하여 $TiO_2$의 미세한 두께조절을 통해 태양전지 성능향상이 가능함을 확인하였다.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.341-341
• /
• 2012

Recently, oxide semi-conductor materials have been investigated as promising candidates replacing a-Si:H and poly-Si semiconductor because they have some advantages of a room-temperature process, low-cost, high performance and various applications in flexible and transparent electronics. Particularly, amorphous indium-gallium-zinc-oxide (a-IGZO) is an interesting semiconductor material for use in flexible thin film transistor (TFT) fabrication due to the high carrier mobility and low deposition temperatures. In this work, we demonstrated improvement of flexibility in IGZO TFTs, which were fabricated on polyimide (PI) substrate. At first, a thin poly-4vinyl phenol (PVP) layer was spin coated on PI substrate for making a smooth surface up to 0.3 nm, which was required to form high quality active layer. Then, Ni gate electrode of 100 nm was deposited on the bare PVP layer by e-beam evaporator using a shadow mask. The PVP and $Al_2O_3$ layers with different thicknesses were used for organic/inorganic multi gate dielectric, which were formed by spin coater and atomic layer deposition (ALD), respectively, at $200^{\circ}C$. 70 nm IGZO semiconductor layer and 70 nm Al source/drain electrodes were respectively deposited by RF magnetron sputter and thermal evaporator using shadow masks. Then, IGZO layer was annealed on a hotplate at $200^{\circ}C$ for 1 hour. Standard electrical characteristics of transistors were measured by a semiconductor parameter analyzer at room temperature in the dark and performance of devices then was also evaluated under static and dynamic mechanical deformation. The IGZO TFTs incorporating hybrid gate dielectrics showed a high flexibility compared to the device with single structural gate dielectrics. The effects of mechanical deformation on the TFT characteristics will be discussed in detail.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2004.08a
• /
• pp.1044-1045
• /
• 2004

In this work, the characteristics of organic thin film transistors (OTFTs) with self-assembled monolayers (SAMs) on polymeric gate insulator have been investigated. The SAMs were formed using atomic layer deposition (ALD) method onto gate insulator. Upon the investigations, it was observed that SAMs modify the wettability of polymeric insulator and influence the growth of subsequent organic semiconductor, and thereby, electric conductivity and roughness of the pentacene film are improved.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2003.11a
• /
• pp.123-123
• /
• 2003

나노튜브는 반도체 재료로서 뿐만 아니라 다른 분야로까지 다양한 응용범위를 가진 물질로서 기존에는 주의 탄소를 사용하여 제작, 사용되어지고 있으나 게이트옥사이드(Gate Oxide) 물질인 지르코니아(ZrO$_2$), 타이타니아(TiO2$_2$) 등을 이용한 나노튜브는 많이 제작되어지고 있지 못하다. 따라서 보다 나은 성질을 갖는 물질로서 나노튜브를 제작할 시 반도체 재료에서의 고집적화를 통해 좋은 성질을 갖게 할 수 있으며 여러 분야로까지 확대가 가능한 재료를 사용하여 광학 및 환경분야 등 응용범위를 넓힐 수 있다. 본 실험은 나노튜브 제작에 있어서 템플레이트의 구멍 내부를 ALD 기술을 이용하여 균일한 두께를 갖는 금속 산화물층을 성장시킨 후 템플레이트 재료의 식각을 통해 금속산화물 나노튜브가 남아있게 하여 제작하는 방법이다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.27 no.7
• /
• pp.417-427
• /
• 2014

Renewable energy sources such as solar, wind and hydro provides utilizing renewable power and reduce the using fossil fuels. On the other hand, it is too critical to apply power system due to the intermittent nature of renewable energy sources, the continuous fluctuations of the power load, and the storage with high energy density. Energy storage system, including pumped-hydroelectric energy storage, compressed-air energy storage, superconducting magnetic energy storage, and electrochemical devices like batteries, supercapacitors and others have shown that solve some of the challenges. In this paper, we review the current state of applications of energy storage systems, and atomic layer deposition technology, graphene materials on the energy storage systems and processes.

• Applied Science and Convergence Technology
• /
• v.26 no.3
• /
• pp.43-46
• /
• 2017

Aluminum-doped ZnO (AZO) thin films were deposited by atomic layer deposition (ALD) with respect to the Al doping concentrations. In order to explain the chemical stability and electrical properties of the AZO thin films after hydrogen peroxide ($H_2O_2$) solution immersion treatment at room temperature, we investigated correlations between the electrical resistivity and the electronic structure, such as chemical bonding state, conduction band, band edge state below conduction band, and band alignment. Al-doped at ~ 10 at % showed not only a dramatic improvement of the electrical resistivity but also excellent chemical stability, both of which are strongly associated with changes of chemical bonding states and band edge states below the conduction band.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2003.07a
• /
• pp.924-927
• /
• 2003

Aluminium-doped ZnO (ZnO:Al) films were grown by atomic layer-controlled deposition on glass substrates at temperature of 200 $^{\circ}C$ using diethylzinc($Zn(C_{2}H_{2})_{2}$; DEtZn), water($H_{2}O$) and trimethylaluminium ($Al(CH_{3})_{3}$; TMA) as precursors. As the cycle ratio of TMA to DEZn(TMA/DEZn) increased, the resistivity of the films decreased and the roughness increased. In the case of TMA/DEZn pulse ratio of 1 to 10, the film had a resistivity of $9.7{\times}l0^{-4}{\Omega}{\cdot}cm$ and a roughness of 2.25nm(rms), while in the case of only DEZ injection the film had a resistivity of $3.5{\times}10^{-3}{\Omega}{\cdot}cm$ and a roughness of 1.07nm(rms)

• Proceedings of the International Microelectronics And Packaging Society Conference
• /
• 2003.11a
• /
• pp.185-190
• /
• 2003

고유전물질인 $HfO_2$ 극박막에 사용될 TaN metal 전극에 대한 특성에 대한 연구를 하였다. 고유전물질인 $HfO_2$는 4" p-type wafer를 SCI cleaning후 ALD(atomic layer deposition)을 통해 $50\AA$를 증착하였다. Ff source는 TEMAH를 이용하였으며 Oxygen source는 $H_2O$를 이용하였다. 이렇게 증착한 $HfO_2$ 극박막에 Ta target을 이용하여 질소 가스를 Ar가스에 첨가하여 reactive sputtering을 통해서 TaN 전극을 증착하였다. TaN 박막의 증착두께는 a--step과 TEM을 통해서 확인하였으며 면저항은 four point probe를 이용하여 측정하였다. 이렇게 증착된 $HfO_2/TaN$구조에 대한 전기적 특성을 측정하였다.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.08a
• /
• pp.81-81
• /
• 2010

Growth of TiO2 films prepared by atomic layer deposition (ALD) was studied on C fiber. Moreover, adsorption and photocatalytic decomposition of methylene blue on TiO2 thin films were studied. Preferential growth of TiO2 on steps of C surfaces could be identified by scanning electron microscopy (SEM). X-ray Photoelectron Spectroscopy (XPS) showed thickness-dependent positive core level shift of Ti, which can be interpreted in terms of enhanced final state charging for thicker films. Adsorption and photocatalytic behaviors of TiO2 thin films will be discussed in this poster.