ZnO/Cu/ZnO (ZCZ) thin films were deposited at room temperature on a glass substrate using direct current (DC) and radio frequency (RF, 13.56 MHz) magnetron sputtering and then the effect of post-deposition electron irradiation on the structural, optical, electrical and transparent heater properties of the films were considered. ZCZ films that were electron beam irradiated at 500 eV showed an increase in the grain sizes of their ZnO(102) and (201) planes to 15.17 nm and 11.51 nm, respectively, from grain sizes of 13.50 nm and 10.60 nm observed in the as deposited films. In addition, the film’s optical and electrical properties also depended on the electron irradiation energies. The highest opto-electrical performance was observed in films electron irradiated at 500 eV. In a heat radiation test, when a bias voltage of 18 V was applied to the film that had been electron irradiated at 500 eV, its steady state temperature was about 90.5 °C. In a repetition test, it reached the steady state temperature within 60 s at all bias voltages.

산화아연 막은 투명한 전도성 물질로써 다양한 분야의 광전자소자에 이용되고 있다. 그러므로 산화아연 막의 특성을 규명하는 것은 광전자소자의 성능을 높이는데 매우 중요한 역할을 할 것이다. 본 논 문에서는 이러한 산화아연 막을 용액공정 기반으로 제작하여 형태적, 구조적 특성을 평가하고자 한다. 구 체적으로는 졸-겔 방법을 반복적으로 시행하여, 시행 횟수에 따른 산화아연 막의 물성의 변화를 관찰할 것 이다. 일정한 용액 조건하에서, 5회의 반복적인 졸-겔 방법을 시행한 결과 결정화가 진행되는 것을 확인하 였다. 7회 이상에서는 원소 구성 및 결정화도가 특정 값에 수렴하는 경향을 보였다. 최종적인 산화아연 막 의 평균결정의 크기는 약 10.7 nm 정도로 계산되었다. 본 연구를 통해 최적의 결정화를 보이는 공정횟수 는 7회였다. 본 연구 결과 및 방법론은 다양한 용액공정 변수를 가변시키면서 적용할 수가 있고 최적의 공 정조건을 확립하는데 기여할 것으로 기대한다.

Tb3+-doped CaNb2O6 (CaNb2O6:Tb3+) thin films were deposited on quartz substrates at a growth temperature of 300 °C using radio-frequency magnetron sputtering. The deposited thin films were annealed at several annealing temperatures for 20 min and characterized for their structural, morphological, and luminescent properties. The experimental results showed that the annealing temperature had a significant effect on the properties of the CaNb2O6:Tb3+ thin films. The crystalline structure of the as-grown CaNb2O6:Tb3+ thin films transformed from amorphous to crystalline after annealing at temperatures greater than or equal to 700 °C. The emission spectra of the thin films under excitation at 251 nm exhibited a dominant emission band at 546 nm arising from the 5D4 → 7F5 magnetic dipole transition of Tb3+ and three weak emission bands at 489, 586, and 620 nm, respectively. The intensity of the 5D4 → 7F5 (546 nm) magnetic dipole transition was greater than that of the 5D4 → 7F6 (489 nm) electrical dipole transition, indicating that the Tb3+ ions in the host crystal were located at sites with inversion symmetry. The average transmittance at wavelengths of 370~1,100 nm decreased from 86.8 % at 700 °C to 80.5 % at an annealing temperature of 1,000 °C, and a red shift was observed in the bandgap energy with increasing annealing temperature. These results suggest that the annealing temperature plays a crucial role in developing green light-emitting CaNb2O6:Tb3+ thin films for application in electroluminescent displays.

Transparent conductive tungsten (W) doped indium oxide (In2O3; IWO) films were deposited at different substrate bias voltage (-Vb) conditions at room temperature on glass substrates by radio frequency (RF) magnetron sputtering and the influence of the substrate bias voltage on the optical and electrical properties was investigated. As the substrate bias voltage increased to -350 Vb, the IWO films showed a lower resistivity of 2.06 × 10-4 Ωcm. The lowest resistivity observed for the film deposited at -350 Vb could be attributed to its higher mobility, of 31.8 cm2/Vs compared with that (6.2 cm2/Vs) of the films deposited without a substrate bias voltage (0 Vb). The highest visible transmittance of 84.1 % was also observed for the films deposited at the -350 Vb condition. The X-ray diffraction observation indicated the IWO films deposited without substrate bias voltage were amorphous phase without any diffraction peaks, while the films deposited with bias voltage were polycrystalline with a low In2O3 (222) diffraction peak and relatively high intensity (431) and (046) diffraction peaks. From the observed visible transmittance and electrical properties, it is concluded that the opto-electrical performance of the polycrystalline IWO film deposited by RF magnetron sputtering can be enhanced with effective substrate bias voltage conditions.

우리나라의 반려동물과 동거하는 반려인은 약1,500만 명에 달한다. 유사이전 사 람이 특정 동물과 상생적 관계의 동거에서 오늘날에는 가족의 형태로까지 발전하 면서 관련 산업이나 보호 등 법적 규제들이 속속 등장하고 있고, 그 동물의 수가 날로 증가하고 있다. 최근 반려동물들은 숏 폼 등과 같은 다양한 영상매체에 등장 함에 따라 콘텐츠의 재미뿐만 아니라 사람들에게 ‘힐링’을 제공하는 중요한 대상 이 되었다. 본고는 같은 시점에서 영화에 반려견이 소재로 등장하여 영화의 또 다 른 재미와 힐링을 제공한다는 점에 주목하였다. 그래서 영화<멍뭉이>의 스토리에 등장하는 애완동물들의 영상 이미지와 등장인물들의 관련 대사들을 통해 힐링요 소을 분석 연구하였다. 영화에 등장하는 애완동물들은 사람의 지속적 관심과 보살 핌의 대상으로 소유 대상이 아닌 애착하는 가족과 같은 대상이라는 영화적 메시 지에 크게 공감한다. 연구결과 관객들은 동물들의 말 없는 움직임의 감정표현 이 미지와 그들을 대상으로 건네는 대사들에서 크게 힐링할 수 있을 것으로 분석되 었다. 연구를 위해 영화와 치유, 영상을 통한 치유 등의 이론을 바탕으로 연구결과를 도출하였다.

Plasma polymerized Styrene thin films were used as a memory layer in a memory device. As for the memory layer, a ppS thin films were used for the organic memory device and their charge storage characteristic was investigated comparatively, where the charge storage effect was evaluated by a hysteresis voltage. The organic memory device with ppS thin film of 30nm and 50nm as memory layer showed promising memory characteristics such as hysteresis voltage of 20V and 28V. The ppS revealed promising charge storage properties which confirms that an organic memory device without floating gate could be successfully implemented by using the ppS thin film as a memory layer.

본 연구는 팀 버튼과 대니 엘프만이 같이 작업한 작품 중, 주어진 현실 세계와 사후 세계를 넘나 드는 영화에서 현실과 비현실, 그로테스크와 유머, 그리고 소외와 포용이라는 이중성을 잘 표현하 는 대표 장면들을 추출하여 분석하였다. 이러한 대표 장면들에 나타난 버튼의 이중성의 의도가 엘 프만 음악에서 음악적 요인들로 어떻게 표현하고 있으며, 어떠한 상관관계를 보이는지에 대해 고찰 하는 것이 본 연구의 목적이다. 그 결과, 팀 버튼 영화에서 나타나는 각 이중성의 관점과 대니 엘 프만의 음악 상관관계 특징을 확인할 수 있었다. 첫째, 그로테스크와 유머이다. 이 관점에서는 반 복되는 리듬 형태에 악기로 변화를 주어 각 등장인물의 움직임 변화를 드러내고, 반음계인 선율과 반복되는 악센트의 변화로 그로테스크와 유머를 가진 캐릭터의 움직임을 형상화한다. 또한 장면의 상황과 같은 배경을 가진 클래식 곡을 차용하여 캐릭터의 특징을 극대화한다. 둘째, 소외와 포용이 다. 이 관점에서는 장면에 부합하는 노래를 차용하여 소외와 포용의 이중성을 드러낸다. 등장인물 이 대사를 하지 않더라도 가사에서 간접적으로 표현을 더하여 인물의 심리를 나타낸다. 이 연구의 제한점으로는 현실과 비현실 이중성 관점과 선과 악 관점의 음악 상관관계를 연구하지 못하였다. 또한 선정한 장면 이외에도 이중성이 드러나는 장면이 존재할 수 있을 것이다. 본 연구를 통해 팀 버튼이 현대사회의 풍자나 소외자들의 포용과 같은 관객들에게 전하고 싶은 메시지와 대니 엘프만 의 영상 음악 표현 방법을 알 수 있었다. 더 나아가 버튼과 엘프만이 함께 작업한 다른 작품들을 더 다양한 이중성 관점으로 영상과 음악의 상관관계에 대한 고찰이 이루어져야 할 것이다.

The surface of carbon films deposited with inverted plasma fireballs is analysed in this paper. Measurements were conducted with Raman spectroscopy, atomic force microscopy and nanoindentation. The latter was used to obtain Young’s modulus as well as Martens and Vickers hardness. The roughness of the film was measured by atomic force microscopy and its thickness was measured. It was shown with Raman spectroscopy that the films are homogeneous in terms of atomic composition and layer thickness over an area of about 125 × 125 mm. Furthermore, it was demonstrated that inverted plasma fireballs are a viable tool for obtaining homogeneous, large area carbon films with rapid growth and very little energy consumption. The obtained films show very low roughness.

Atomic layer etching (ALE) is a promising technique with atomic-level thickness controllability and high selectivity based on self-limiting surface reactions. ALE is performed by sequential exposure of the film surface to reactants, which results in surface modification and release of volatile species. Among the various ALE methods, thermal ALE involves a thermally activated reaction by employing gas species to release the modified surface without using energetic species, such as accelerated ions and neutral beams. In this study, the basic principle and surface reaction mechanisms of thermal ALE?processes, including “fluorination-ligand exchange reaction”, “conversion-etch reaction”, “conversion-fluorination reaction”, “oxidation-fluorination reaction”, “oxidation-ligand exchange reaction”, and “oxidation-conversion-fluorination reaction” are described. In addition, the reported thermal ALE processes for the removal of various oxides, metals, and nitrides are presented.

Among efforts to improve techniques for the chemical vapor deposition of large-area and high-quality graphene films on transition metal substrates, being able to reliably transfer these atomistic membranes onto the desired substrate is a critical step for various practical uses, such as graphene-based electronic and photonic devices. However, the most used approach, the wet etching transfer process based on the complete etching of metal substrates, remains a great challenge. This is mainly due to the inevitable damage to the graphene, unintentional contamination of the graphene layer, and increased production cost and time. Here, we report the systematic study of an H2 bubbling-assisted transfer technique for graphene films grown on Cu foils, which is nondestructive not only to the graphene film but also to the Cu substrate. Also, we demonstrate the origin of the graphene film tearing phenomenon induced by this H2 bubbling-assisted transfer process. This study reveals that inherent features are produced by rolling Cu foil, which cause a saw-like corrugation in the poly(methyl methacrylate) (PMMA)/graphene stack when it is transferred onto the target substrate after the Cu foil is dissolved. During the PMMA removal stage, the graphene tearing mainly appears at the apexes of the corrugated PMMA/graphene stack, due to weak adhesion to the target substrate. To address this, we have developed a modified heat-press-assisted transfer technique that has much better control of both tearing and the formation of residues in the transferred graphene films.

Halide perovskite solar cells (PSCs) have improved rapidly over the past few years, and research on the optoelectrical properties of halide perovskite thin films has grown as well. Among the characterization techniques, photoluminescence (PL), a method of collecting emitted photons to evaluate the properties of materials, is widely applied to evaluate improvements in the performance of PSCs. However, since only photons emitted from the film in the escape cone are included, the photons collected in PL are a small fraction of the total photons emitted from the film. Unlike PSCs power conversion efficiency, PL measuring methods have not been standardized, and have been evaluated in a variety of ways. Thus, an in-depth study is needed of the methods used to evaluate materials using PL spectra. In this study, we examined the PL spectra of the perovskite light harvesting layer with different measurement protocols and analyzed the features. As the incident angle changed, different spectra were observed, indicating that the PL emission spectrum can depend on the measuring method, not the material. We found the intensity and energy of the PL spectra changes were due to the path of the emitted photons. Also, we found that the PL of halide perovskite thin films generally contains limited information. To solve this problem, the emitted photons should be collected using an integrating sphere. The results of this study suggest that the emission spectrum of halide perovskite films should be carefully interpreted in accordance with PL measuring method, since PL data is mostly affected by the method.

본 논문에서는 반도체 특성의 단일벽 탄소나노튜브(semi-SWNTs)와 페로브스카이트(perovskite) 양자 점을 혼합하여 SWNT의 높은 전하 이동 특성과 양자점의 고효율 광전 특성을 동시에 가지는 용액공정 가 능한 기반 고성능 광센서를 개발하기 위한 연구를 수행하였다. 직경이 작은 SWNT를 공액 구조 고분자 반도체를 이용해 선택적으로 분리/분산하는 방법으로 제조하여 포토트랜지스터의 반도체 채널 층으로 활 용하고, 가시광 빛에 높은 흡광도를 가지는 양자점을 다양한 조성과 구조를 가지는 광활성층으로 제조하 여 그 특성을 비교 분석하였다. 이 결과 semi-SWNTs와 페로브스카이트 양자점 모두 단독으로 TFT에 사 용하였을 경우 우수한 트랜지스터 특성과는 별개로 광전효과가 크게 나타나지 않았으며, 두 종류 이상의 반도체 소재를 융합하여 사용할 경우 양자점에 흡수된 빛에 의해 엑시톤이 형성되고 이종 접합 계면에서 전자와 정공의 분리가 쉽게 이루어지도록 유도함으로써 낮은 광량에서도 높은 효율을 가지는 포토트랜지 스터를 개발할 수 있었다. 향후 지속적인 연구개발을 통해 고유연/저가 광 센서 제품 개발과 레이더, 이미 지 센서, 웨어러블 헬스케어 등의 다양한 분야에 하이브리드 반도체 포토트랜지스터가 응용될 수 있을 것 으로 기대한다.

Large-area graphene of the order of centimeters was deposited on copper substrates by low-pressure chemical vapor deposition (LPCVD) using hexane as the carbon source. The effect of temperature and the carrier gas flowrates on the quality and uniformity of the as-deposited graphene was investigated using the Raman analysis. The film deposited at 870 °C with a total carrier gas flowrate of 50 sccm is predominantly single-layer with very low defects according to the Raman spectra. The 2D/G peak intensity ratios obtained from the Raman spectra of samples from three different locations of graphene deposited on a whole copper catalyst was used to calculate the large-area uniformity. Based on the results, a very high uniformity of 89.6% was calculated for the graphene deposited at 870 °C. The uniformity was observed to decrease with increasing temperature. Similar to the thickness uniformity, the electrical conductivity values obtained as a result of I–V measurements and water contact angle measurements were found to be close to each other for the graphene deposited under the same deposition conditions.

Transparent thin films of pure and nickel-doped ZrO2 are grown successfully by sol-gel dip-coating technique. The structural and optical properties according to the different annealing temperatures (300 oC, 400 oC and 500 oC) are investigated. Analysis of crystallographic properties through X-ray diffraction pattern reveals an increase in crystallite size due to increase in crystallinity with temperature. All fabricated thin films are highly-oriented along (101) planes, which enhances the increase in nickel doping. Scanning electron microscopy and energy dispersive spectroscopy are employed to confirm the homogeneity in surface morphology as well as the doping configuration of films. The extinction coefficient is found to be on the order of 102, showing the surface smoothness of deposited thin films. UV-visible spectroscopy reveals a decrease in the optical band gap with the increase in annealing temperature due to the increase in crystallite size. The variation in Urbach energy and defect density with doping and the change in annealing temperature are also studied.

일상적인 화학제품들의 사용량이 증가함에 따라 사용되었던 염료 폐기물 처리 또한 중요한 환경 적인 문제로 대두되었다. 이러한 염료폐기물은 광촉매를 이용하여 분해시킬 수 있는데, 졸-겔 기술을 활용 하면 매우 비용 효율적으로 광촉매를 합성할 수 있다. 졸-겔 기술은 나노스케일의 막 형성에도 상당히 유 용하며 간단하게 다층구조를 형성할 수도 있다. 본 연구에서는 다양한 염료 분해에 효과가 있는 산화아연 (ZnO) 이용하여 다중 회전도포 방법으로 다층구조(3층, 5층)를 가진 ZnO 막을 형성하였다. 성능비교를 위해 단일 회전도포 방법에 의한 단층구조를 가진 ZnO 막을 대조군으로 준비하였다. X선 회절분석기 및 에너지 분산 X선 분광계를 이용하여 ZnO의 구조 및 원소분석을 수행하였고, 주사전자현미경을 통해 나노 선같은 표면형상을 관찰할 수 있었다. 추가적으로 UV-Vis 분광광도계를 활용하여 자외선의 흡수도를 측정 하였다. 5층구조를 가진 ZnO 막이 단층 구조를 가진 ZnO 막에 비해 모의 메틸렌 블루를 49% 더 많이 분해하였다. 결론적으로, 다층구조를 가진 ZnO 는 메틸렌블루 염료를 더욱 효과적으로 분해하는 광촉매로 써 유용하다는 알 수 있었다.

Aluminum nitride having a dense hexagonal structure is used as a high-temperature material because of its excellent heat resistance and high mechanical strength; its excellent piezoelectric properties are also attracting attention. The structure and residual stress of AlN thin films formed on glass substrate using TFT sputtering system are examined by XRD. The deposition conditions are nitrogen gas pressures of 1 × 102, 6 × 103, and 3 × 103, substrate temperature of 523 K, and sputtering time of 120 min. The structure of the AlN thin film is columnar, having a c-axis, i.e., a <00·1> orientation, which is the normal direction of the glass substrate. An X-ray stress measurement method for crystalline thin films with orientation properties such as columnar structure is proposed and applied to the residual stress measurement of AlN thin films with orientation <00·1>. Strength of diffraction lines other than 00·2 diffraction is very weak. As a result of stress measurement using AlN powder sample as a comparative standard sample, tensile residual stress is obtained when the nitrogen gas pressure is low, but the gas pressure increases as the residual stress is shifts toward compression. At low gas pressure, the unit cell expands due to the incorporation of excess nitrogen atoms.

K0.5Bi0.5TiO3 (KBT) thin films were prepared by sol-gel processing for future use in piezoelectric generators. It is believed that the annealing temperature of films plays an important role in the output performance of piezoelectric generators. KBT films prepared on Ni substrates were annealed at 500 ~ 700 oC. Tetragonal KBT films were formed after annealing process. As the annealing temperature increased, the grain size of KBT films increased. KBT thin films show piezoelectric constant (d33) from 23 to 41 pC/N. The increase of grain size in KBT films brought about output voltage and current in the KBT generators. Also, the increase in the displacement of specimens during bending test resulted in increases in output voltage and current. Although KBT generators showed lower output power than those of generators prepared using NBT films, as reported previously, the KBT films prepared by sol-gel method show applicability as piezoelectric thin films for lead-free nanogenerators, along with NBT films.