In this study, we investigate the effect of the diffusion barrier and substrate temperature on the length of carbon nanotubes. For synthesizing vertically aligned carbon nanotubes, thermal chemical vapor deposition is used and a substrate with a catalytic layer and a buffer layer is prepared using an e-beam evaporator. The length of the carbon nanotubes synthesized on the catalytic layer/diffusion barrier on the silicon substrate is longer than that without a diffusion barrier because the diffusion barrier prevents generation of silicon carbide from the diffusion of carbon atoms into the silicon substrate. The deposition temperature of the catalyst and alumina are varied from room temperature to 150°C, 200°C, and 250°C. On increasing the substrate temperature on depositing the buffer layer on the silicon substrate, shorter carbon nanotubes are obtained owing to the increased bonding force between the buffer layer and silicon substrate. The reason why different lengths of carbon nanotubes are obtained is that the higher bonding force between the buffer layer and the substrate layer prevents uniformity of catalytic islands for synthesizing carbon nanotubes.

The effects of electron beam(EB) irradiation on the electrical and optical properties of InGaZnO(IGZO) thin films fabricated using a sol-gel process were investigated. As the EB dose increased, the electrical characteristic of the IGZO TFTs changed from semiconductor to conductor, and the threshold voltage values shifted to the negative direction. X-ray photoelectron spectroscopy analysis of the O 1s core level showed that the relative area of oxygen vacancies increased from 14.68 to 19.08 % as the EB dose increased from 0 to 1.5 × 1016 electrons/cm2. In addition, spectroscopic ellipsometer analysis showed that the optical band gap varied from 3.39 to 3.46 eV with increasing EB dose. From the result of band alignment, it was confirmed that the Fermi level(EF) of the sample irradiated with 1.5 × 1016 electrons/cm2 was located at the closest position to the conduction band minimum(CBM) due to the increase of electron carrier concentration

Porous polytetrafluoroethylene (PTFE) thin films are fabricated by spin-coating using a dispersion solution containing PTFE powders, and their crystalline properties are investigated after thermal annealing at various temperatures ranging from 300 to 500°C. Before thermal annealing, the film is densely packed and consists of many granular particles 200-300 nm in diameter. However, after thermal annealing, the film contains many voids and fibrous grains on the surface. In addition, the film thickness decreases after thermal annealing owing to evaporation of the surfactant, binder, and solvent composing the PTFE dispersion solution. The film thickness is systematically controlled from 2 to 6.5 μm by decreasing the spin speed from 1,500 to 500 rpm. A triboelectric nanogenerator is fabricated by spin-coating PTFE thin films onto polished Cu foils, where they act as an active layer to convert mechanical energy to electrical energy. A triboelectric nanogenerator consisting of a PTFE layer and Al metal foil pair shows typical output characteristics, exhibiting positive and negative peaks during applied strain and relief cycles due to charging and discharging of electrical charge carriers. Further, the voltage and current outputs increase with increasing strain cycle owing to accumulation of electrical charge carriers during charge-discharge.

FO is prominent membrane technology for desalination due to no hydraulic pressure requirement and low fouling propensity compared to RO. TFC membrane was widely used due to excellent perm-selectivity and chemical resistance. TFC membrane consists of dense and support layer. Academic efforts focused on advance TFC membranes characteristics and performances. This work attempts to fabricate TFC FO membrane with highly permeable ultra-thin intermediate layer on the support layer using polydopamine and graphene oxide. Role of the intermediate layer on performances was demonstrated via characterization and FO operation.

In this study, we present a unique surface modification method for a water desalination membrane to control the surface fouling via titanium dioxide (TiO2) nanopillar pattern imprinting. The patterned membranes showed significantly improved fouling resistance for both organic protein and bacterial foulants compared to the nonpatterned membranes. The hydrophilicity of TiO2 used as a pattern material affects the improvement of chemical antifouling resistance of the membrane. Fouling behavior was also interpreted in terms of the topographical effect depending on the relative size of foulants to the pattern dimension. Moreover, the computational fluid dynamics simulation intimates that the overall and local shear stress enhancement on the patterned surface could affect the foulant deposition behavior on the membrane.

We report on a unique fabrication technique, DSC for high performance PA TFC RO membranes. DSC allows the simultaneous and continuous spreading of two reactive monomer solutions to create an unsupported PA layer, which is then adhered onto a porous support to form a membrane. DSC facilitates the characterization of the PA layer structure by easily isolating it. The DSC-PA layer exhibits a thinner and smoother structure with a more wettable and less negatively charged surface than one prepared via conventional interfacial polymerization (IP). DSC enables the formation of an extremely thin (~9 nm) and dense PA layer using a very low MPD concentration, which is not feasible by conventional IP. Importantly, the DSC-assembled membrane shows the excellent water flux and NaCl rejection, exceeding both the IP control and commercial RO membranes.

A salinity gradient power (SGP) system holds a great potential to generate continuous and clean electricity for 24 hours. Recently, incorporating with seawater reverse osmosis, SGP has been recognized as a alternative to solve the brine issue as well as energy saving. For commercialization, many scientists would sympathize that one of main hurdles is the limited performance of each membrane to extract the high power. In case of pressure retarded osmosis (PRO) closer to commercialization, the membrane must have the high water permeability and salt rejection. There are two type of modules; hollow fiber membranes and spiral type. Toray Chem. (Korea) already shows that 4th generation PRO module, but there is no still large size PRO hollow fiber modules. Therefore, this study presents 2 and 3 inch size of PRO hollow fiber membrane prepared by inside interfacial polymerization techniques.

Owing to high energy efficiency and superior efficacy, membrane-based desalination processes have gained widespread implementation in a wide variety of water treatment applications. Tremendous research efforts on new membrane materials have been made to improve the separation performance of the state-of-the-art thin-film composite (TFC) membranes, particularly polyamide TFC membranes, hoping to overcome the permeability-selectivity trade-off relations. Currently, many nanomaterials such as zeolites, metal-organic frameworks (MOFs), graphene oxide (GO), and carbon nanotubes (CNTs) have been explored to enhance the separation performance of existing polymeric membranes, but it has been argued that the positive transformation of nanomaterials-embedded TFC membranes hold promising potential to realize the sustainable development of current desalination membranes. Here we have tried to discuss some misconceptions and challenging items delaying industrial-scale implementation of nanomaterialsembedded desalination membranes.

The effect of electron beam (EB) irradiation on the electrical properties of Zn-Sn-O (ZTO) thin films fabricated using a sol-gel process was investigated. As the EB dose increased, the saturation mobility of ZTO thin film transistors (TFTs) was found to slightly decrease, and the subthreshold swing and on/off ratio degenerated. X-ray photoelectron spectroscopy analysis of the O 1s core level showed that the relative area of oxygen vacancies (VO) increased from 10.35 to 12.56 % as the EB dose increased from 0 to 7.5 × 1016 electrons/cm2. Also, spectroscopic ellipsometry analysis showed that the optical band gap varied from 3.53 to 3.96 eV with increasing EB dose. From the results of the electrical property and XPS analyses of the ZTO TFTs, it was found that the electrical characteristic of the ZTO thin films changed from semiconductor to conductor with increasing EB dose. It is thought that the electrical property change is due to the formation of defect sites like oxygen vacancies.

We have demonstrated the production of thin films containing multilayer graphene-coated copper nanoparticles (MGCNs) by a commercial electrodeposition method. The MGCNs were produced by electrical wire explosion, an easily applied technique for creating hybrid metal nanoparticles. The nanoparticles had average diameters of 10–120 nm and quasi-spherical morphologies. We made a complex-electrodeposited copper thin film (CETF) with a thickness of 4.8 μm by adding 300 ppm MGCNs to the electrolyte solution and performing electrodeposition. We measured the electric properties and performed corrosion testing of the CETF. Raman spectroscopy was used to measure the bonding characteristics and estimate the number of layers in the graphene films. The resistivity of the bare-electrodeposited copper thin film (BETF) was 2.092 × 10–6 Ω·cm, and the resistivity of the CETF after the addition of 300 ppm MGCNs was decreased by 2% to ~2.049 × 10–6 Ω·cm. The corrosion resistance of the BETF was 9.306 Ω, while that of the CETF was increased to 20.04 Ω. Therefore, the CETF with MGCNs can be used in interconnection circuits for printed circuit boards or semiconductor devices on the basis of its low resistivity and high corrosion resistance.

Graphene oxide (GO) has received a lot of attention in membrane science for its CO2-philic nature, which can facilitate CO2 separation performance. In addition, GO has attractive properties for gas separation membrane material due to thin-film membrane formation and tunable transport channel. GO membrane can be generally prepared by coating GO nanosheets on microporous polymer supports for mechanical stability. However, the substrates for in thin GO layer should be carefully chosen for good adhesion between GO layer and support surface with maintaining good separation performance. In this study, we tried to modify the surface properties of high permeable support membranes by using gutter layer as an intermediate layer, and measured the gas transport properties of these GO thin-film composite membranes.

본 연구에서는 폴리술폰층 표면에 계면 중합 반응을 시켜 정삼투 복합 박막을 얻는 방법에 있어서, 지지층인 폴 리술폰층과 활성층인 폴리아미드층 사이에 테트라에톡시실란 단량체의 졸-젤 반응을 통하여 고분자를 합성함으로써 친수성 경계층을 형성시키는 방법에 관한 제조법을 제시하였다. 폴리술폰층은 막 저항을 최소화하기 위하여 아주 얇은 부직포를 사 용하였다. 테트라에톡시실란의 졸-젤 반응으로 형성된 고분자 경계층이 폴리술폰층과 폴리아미드층 사이에 형성된 정삼투 분 리막은 친수화도, 유량 향상 등 정삼투 분리막 투과 특성에 있어 향상된 결과를 보여 주었다. 폴리아미드 계면 중합과 테트라 에톡시실란 졸-젤 중합의 순서를 변화시킴으로써 표면 구조 특성 및 정삼투 투과 특성이 크게 달라짐을 볼 수 있었다. 정삼투 막의 투과 특성은 실험실 용량의 정삼투 평가 장치를 통하여, 정삼투 분리막 내 폴리실록산의 분포와 구조는 FE-SEM과 EDAX를 이용하여 조사하였다. PS_PA_TEOS막의 경우 유량에 있어 79.2 LMH로 현격한 증가가 있었으나 염의 역확산 속도 역시 7.10 GMH로 증가하였다. 반면 PS_TEOS_PA막의 경우 PS_PA막에 비해 염의 역확산 속도는 1.60 GMH로 유지되면서 유량이 54.1 LMH로 증가하는 현상을 확인할 수 있었다.

Tungsten (W) thin film was deposited at 400 oC using pulsed chemical vapor deposition (pulsed CVD); film was then evaluated as a nucleation layer for W-plug deposition at the contact, with an ultrahigh aspect ratio of about 14~15 (top opening diameter: 240~250 nm, bottom diameter: 98~100 nm) for dynamic random access memory. The deposition stage of pulsed CVD has four steps resulting in one deposition cycle: (1) Reaction of WF6 with SiH4. (2) Inert gas purge. (3) SiH4 exposure without WF6 supply. (4) Inert gas purge while conventional CVD consists of the continuous reaction of WF6 and SiH4. The pulsed CVD-W film showed better conformality at contacts compared to that of conventional CVD-W nucleation layer. It was found that resistivities of films deposited by pulsed CVD were closely related with the phases formed and with the microstructure, as characterized by the grain size. A lower contact resistance was obtained by using pulsed CVD-W film as a nucleation layer compared to that of the conventional CVD-W nucleation layer, even though the former has a higher resistivity (~100 μΩ-cm) than that of the latter (~25 μΩ-cm). The plan-view scanning electron microscopy images after focused ion beam milling showed that the lower contact resistance of the pulsed CVD-W based W-plug fill scheme was mainly due to its better plug filling capability.

We developed an Al sputtering process by varying the plasma power, process temperature, and film thickness. We observed an increase of hillock distribution and average diameter with increasing plasma power, process temperature, and film thickness. Since the roughness of a film increases with the increase of the distribution and average size of hillocks, the control of hillock formation is a key factor in the reduction of Al corrosion. We observed the lowest hillock formation at 30 W and 100 oC. This growth characteristic of sputtered Al thin films will be useful for the reduction of Al corrosion in the future of the electronic packaging field.

정삼투 분리막 용도에 적합한 폴리아미드 복합막의 제조에 있어 지지층의 극성 및 공극률이 폴리아미드 구조 및 정삼투 분리막 투과 성능에 미치는 영향을 살펴보기 위하여 클레쏘킬레이트 금속착물(0.1-0.5중량%)이 함유된 폴리술폰(18중 량%) 용액을 상전이 공정을 통하여 지지층을 제조하였다. 제조된 지지층 상에 방향족 폴리아미드 활성층을 제막하였다. 다공 성 PSF 지지층 제조를 위하여 상대적으로 낮은 폴리술폰(12중량%) 용액을 이용한 지지층을 폴리에스터 필름상에서 제조한 후 필름을 제거하고 제조된 지지층 상에 방향족 폴리아미드 활성층을 제막하였다. 제막된 시편 중 폴리술폰(18중량%)/금속착 물(0.5중량%)로 만들어진 FO막은 유량 9.99 LMH, reverse salt flux 0.77 GMH로 HTI의 상용막(10.97 LMH, 2.2 GMH)과 비교해도 거의 비슷한 유량값과 향상된 RSF 값을 얻을 수 있었다. 캐스팅 용액의 금속착물의 첨가로 활성층 두께가 줄어들 었으나 제거효율은 향상되는 결과를 얻을 수 있었다.

Magnetostrictive actuator is fabricated with powder nano bonding method instead of sputtering method. Fabrication process and experimental measurement method for magneto-mechanical characteristics is proposed. For the design of highly flexible magnetostrictive actuator, TbDyFe nano powder bonding with Teflon substrate is adopted. The fabrication process for Teflon substrate and nano powder bonding is suggested and magnetostrictive behaviors are investigated. Variable magnetic field is applied to measure the magnetostrictive characteristics and magnetostriction is measured with different waves and different magnitude of magnetic field.

Thin-film composite (TFC) membrane is currently the most widely used membrane structure for reverse osmosis (RO) process. Most commercial membrane for RO consisted of porous support layer and dense polyamide permselective layer, yet the polyamide layer has a very rough surface morphology and considerable thickness, and these features are intrinsic properties of current RO membrane fabrication process. In this study, we present the new membrane fabrication, named layered interfacial polymerization (LIP). LIP could control the roughness and thickness of permselective layer without complicated process or significant membrane performance loss, and the performance itself was comparable to conventional IP membrane. Moreover, the fabricated membrane has a remarkable antifouling ability possibly due to the unique smooth morphology.

20 μm의 얇은 폴리에스터(polyester) 부직포 상에 폴리술폰(polysulfone) 고분자 지지체를 제조하였다. 폴리아미드 계면 중합이 일어날 폴리술폰 표면에 폴리 실록산 층이 형성될 수 있도록 실란 화합물을 중합하여 폴리실록산 지지체를 제조하였다. 얻어진 복합막 지지층에서 MPD 수용액과 TMC 유기용액을 계면 중합을 실시한 결과 정삼투 분리용 복합박막을 얻을 수 있었다. FE-SEM을 이용하여 지지층의 구조가 sponge-like 구조임을, EDX를 통하여 폴리실록산이 표면에 한하여 분포됨을 확인하였으며 1 M NaCl 유도용액하에서의 FO-mode 유량 이 79.2 - 117 LMH로 향상되었으며 RSF값은 2.12 - 7.97 GMH로 유지함을 확인할 수 있었다.

Tin oxides have been studied for various applications such as gas detecting materials, transparent electrodes, transparent devices, and solar cells. p-type SnO is a promising transparent oxide semiconductor because of its high optical transparency and excellent electrical properties. In this study, we fabricated p-type SnO thin film using rf magnetron sputtering with an SnO/Sn composite target; we examined the effects of various oxygen flow rates on the SnO thin films. We fundamentally investigated the structural, optical, and electrical properties of the p-type SnO thin films utilizing X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV/Vis spectrometry, and Hall Effect measurement. A p-type SnO thin film of PO2 = 3 % was obtained with > 80 % transmittance, carrier concentration of 1.12 × 1018 cm−3, and mobility of 1.18 cm2V− 1s−1. With increasing of the oxygen partial pressure, electrical conductivity transition from p-type to n-type was observed in the SnO crystal structure.