• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.184-185
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• 2006

Two-step growth to incorporate the Mg atoms in the ZnO nanorods fabricate by thermal evaporation process and also utilized the ZnO film as a template. In the first step of low temperature, Zn seed metals with low melting temperature formed the droplet, and then MgZnO ternary nanorods were grown by injecting oxygen and evaporating Mg atoms in high temperature process of the second step. The vertical growth of the MgZnO nanorods with large-area distribution and uniformity was successfully performed on the ZnO template. We investigated the shape of the vertically grown 1-D MgZnO nanorods and characterized the optical and crystal properties. We confirmed the incorporation of Mg atoms by the EDS and PL spectrum.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2005년도 춘계종합학술대회
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• pp.1034-1037
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• 2005

Si (111) 기판 상에 전자빔 증착법으로 Ni, Cr 금속 패턴을 형성시킨 후, 그 금속 패턴 위에 대기 중에서 열 증착법으로 Zn powder를 사용하여 ZnO 나노 구조를 형성시켰다. 형성 시 기판의 온도는 500 ${\sim}$ 700 $^{\circ}$C의 범위에서 설정하였다. 금속 촉매 상에 형성된 ZnO 나노 구조와, Si 기판 상에 형성된 ZnO 나노 구조에서 각각의 형성된 나노 구조의 형상과 이에 따른 나노 구조의 특성 변화를 관찰하였다. 형성된 시료의 발광 특성은 실온에서 He-Cd laser (325 nm)를 이용하여 조사하였고, 금속 패턴 상에 형성된 나노 구조와 Si 기판 상에 형성된 나노 구조의 형상 차이를 광학 현미경과 Scanning Electron Microscope (SEM)을 이용하여 관찰하였다. 그 결과 기판의 온도가 비교적 저온일 때에는 촉매에 의한 영향을 관찰할 수 없었으나 성장 온도가 700 $^{\circ}$ 이상의 고온에서는 금속 촉매가 발광 특성 및 나노 구조의 형상에 영향을 주는 것을 알 수 있었다.

• 한국세라믹학회지
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• 제54권3호
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• pp.167-183
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• 2017

Zinc oxide (ZnO) is one of the most versatile semiconductors, and one-dimensional (1D) ZnO nanostructures have attracted significant interest for use in ultraviolet (UV) lasers, photochemical sensors, and photocatalysts, among other applications. It is known that 1D ZnO nanowires can be fabricated readily owing to the anisotropic growth of ZnO along the [0001] direction. However, this type of growth results in a decrease in the surface area of the (0001) plane, which plays a vital role not only in UV lasing but also in the photocatalytic process. Thus, we attempted to synthesize ZnO crystals with an increased polar surface area by controlling the crystal growth process. The purpose of this review is to propose a simple route for the synthesis of plate-like ZnO crystals with highly enhanced polar surfaces and to explore their feasibility for use in UV lasers as well as as a photocatalyst and antibacterial agent. In addition, we highlight the recent progress made in the pilot-scale synthesis of plate-like ZnO crystals for industrial applications.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 추계학술발표대회
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• pp.27.1-27.1
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• 2009

In recent years, ZnO nanostructures have drawn considerable attentions for the development of futuristic electronic devices due to their superior structural and optical properties. As the growth of ZnO nanowires by MOCVD is a bottom-up technique, the nature of substrates has a vital role for the dimension and alignment of the nanowires. However, in the pursuit of next generation ZnO based nanodevices, it would be highly preferred if well-ordered ZnO nanowires could be obtained on various substrates like sapphire, silicon, glass etc. Vertically aligned nanowires were grown on A and C-plane sapphire substrates, where as nanopencils were obtained on R-plane sapphire substrates. In addition, C-axis oriented vertical nanowires were also found using an interfacial layer(aluminum nitride film) on silicon substrates. On the other hand, long nanowires were found on Ga-doped ZnO film on glass substrates. Structural and optical properties of the ZnO nanowires on various substrates were also investigated.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.672-672
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• 2013

본 연구에서는 수열합성법을 기반으로 한 3차원 ZnO 나노구조의 합성을 통해 효율적인 양자점 감응형 태양전지로의 응용을 하고 그 특성을 평가하였다. 기존의 1차원 ZnO 나노구조의 경우 높은 전자이동도와 구조적으로 얻을 수 있는 방향성 있는 전자의 효율적인 전달을 통해 효과적인 광전극으로 많은 관심을 받아왔다. 하지만 나노파티클 기반의 필름에 비해 표면적이 크게 떨어지기 때문에 효과적인 흡광이 어렵다는 단점이 존재하여 높은 효율특성을 내지는 못하였다. 본 연구에서는 이러한 단점을 극복하면서 기존 ZnO 나노선의 장점을 극대화 하기 위해 성장시킨 ZnO 나노선 위에 추가적으로 가지를 형성하여 표면적 향상과 효과적인 전자전달 특성을 얻고자 하였다. 3차원 ZnO 나노구조는citrate 계열의 capping agent의 첨가를 통한 수열 합성법을 통해 1차원의 ZnO 나노선 위에 nanosheet 형식의 가지를 형성하였고 이는 빛의 효과적인 산란특성 및 표면적 향상을 통한 CdS, CdSe의 양자점 증착량을 증가시키는 효과를 얻을 수 있었다. 이러한 태양전지의 소자 특성은 SEM, TEM을 통한 구조 특성평가 및 DRS, J-V curve 및 IPCE를 통한 광학적 특성평가를 통해 확인하였다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2009년도 춘계학술대회 논문집
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• pp.99-99
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• 2009

차세대 대체에너지로서 유기태양전지는 저비용, flexible한 장점이 있다. 그러나 에너지 효율이 상대적으로 낮아 고효율 유기태양전지 개발이 필요하다. 이 문제를 개선하기위해 본 실험에서는 전기화학적인 방법으로 ZnO 나노구조체 (nanowire, film)를 ITO위에 전착하였다. ZnO 나노구조체는 Poly(3-hexylthiophene)(P3HT):[6,6]-Phnyl-C61-butyric acid methyl ester (PCBM)에서 엑시톤된 전자와 홀의 charge collector와 electron path way로서 사용되었다. 유/무기 하이브리드 태양전지의 구조는 Ag/P3HT:PCBM/(A)/ITO로 사용하였으며 (A)는 (1) ZnO nanowire/ZnO film (2)ZnO nanowire (3)ZnO film으로, 각각의 효율을 측정하였다. 생성된 ZnO 나노구조를 FE-SEM, XRD, TEM, UV/vis로 분석하였고 AM1.5G SUN을 기준으로 하여 Solar simulator로 효율을 측정하였다. 측정결과 Jsc값의 증가를 효율이 향상됨을 알 수 있었다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2007년도 추계학술발표대회 및
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• pp.20.2-20.2
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• 2007

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2005년도 추계학술강연 및 발표대회강연 및 발표논문 초록집
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• pp.47-48
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• 2005

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2006년도 추계학술발표회 초록집
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• pp.10-10
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• 2006

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.993-994
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• 2008

Electrochromic (EC) devices are capable of reversibly changing their optical properties upon charge injection and extraction induced by the external voltage. The characteristics of the EC device, such as low power consumption, high coloration efficiency, and memory effects under open circuit status, make them suitable for use in a variety of applications including smart windows and electronic papers. Coloration due to reduction or oxidation of redox chromophores can be used for EC devices (e-paper), but the switching time is slow (second level). Recently, with increasing demand for the low cost, lightweight flat panel display with paper-like readability (electronic paper), an EC display technology based on dye-modified $TiO_2$ nanoparticle electrode was developed. A well known organic dye molecule, viologen, was adsorbed on the surface of a mesoporous $TiO_2$ nanoparticle film to form the EC electrode. On the other hand, ZnO is a wide bandgap II-VI semiconductor which has been applied in many fields such as UV lasers, field effect transistors and transparent conductors. The bandgap of the bulk ZnO is about 3.37 eV, which is close to that of the $TiO_2$ (3.4 eV). As a traditional transparent conductor, ZnO has excellent electron transport properties, even in ZnO nanoparticle films. In the past few years, one-dimension (1D) nanostructures of ZnO have attracted extensive research interest. In particular, 1D ZnO nanowires renders much better electron transportation capability by providing a direct conduction path for electron transport and greatly reducing the number of grain boundaries. These unique advantages make ZnO nanowires a promising matrix electrode for EC dye molecule loading. ZnO nanowires grow vertically from the substrate and form a dense array (Fig. 1). The ZnO nanowires show regular hexagonal cross section and the average diameter of the ZnO nanowires is about 100 nm. The cross-section image of the ZnO nanowires array (Fig. 1) indicates that the length of the ZnO nanowires is about $6\;{\mu}m$. From one on/off cycle of the ZnO EC cell (Fig. 2). We can see that, the switching time of a ZnO nanowire electrode EC cell with an active area of $1\;{\times}\;1\;cm^2$ is 170 ms and 142 ms for coloration and bleaching, respectively. The coloration and bleaching time is faster compared to the $TiO_2$ mesoporous EC devices with both coloration and bleaching time of about 250 ms for a device with an active area of $2.5\;cm^2$. With further optimization, it is possible that the response time can reach ten(s) of millisecond, i.e. capable of displaying video. Fig. 3 shows a prototype with two different transmittance states. It can be seen that good contrast was obtained. The retention was at least a few hours for these prototypes. Being an oxide, ZnO is oxidation resistant, i.e. it is more durable for field emission cathode. ZnO nanotetropods were also applied to realize the first prototype triode field emission device, making use of scattered surface-conduction electrons for field emission (Fig. 4). The device has a high efficiency (field emitted electron to total electron ratio) of about 60%. With this high efficiency, we were able to fabricate some prototype displays (Fig. 5 showing some alphanumerical symbols). ZnO tetrapods have four legs, which guarantees that there is one leg always pointing upward, even using screen printing method to fabricate the cathode.