• 전자공학회논문지D
• /
• 제35D권12호
• /
• pp.48-52
• /
• 1998

본 논문에서는 SOI 기판 위에 새롭게 제안된 측면 채널과 나노 점을 갖는 나노 구조의 기억소자를 제작하였다. Top-silicon의 측면이 채널영역이 되고 나노 점이 이 채널 영역의 위에 반응성 이온 식각(RIE)에 의해 형성되는 구조를 가지는 이 소자는 측면 채널(edge channel)의 너비가 SOI기판의 열산화에 의해 얇아진 top-silicon의 두께에 의해 결정되고, 나노 점의 크기는 반응성 이온 식각(RIE) 및 전자선 직접 묘화에 의해 결정된다. 제작된 나노 구조 소자의 I/sub d/-V/sub d/, I/sub d/-V/sub g/ 특성 및 -20V에서 +14V까지의 게이트 전압 영역에서 문턱전압의 변화 범위가 약 1V정도 되는 기억소자의 특성을 얻었다.

• 전기학회논문지
• /
• 제65권12호
• /
• pp.2014-2018
• /
• 2016

Transparent, conductive electrode films, showing the particular characteristics of good conductivity and high transparency, are of considerable research interest because of their potential for use in opto-electronic applications, such as smart window, photovoltaic cells and flat panel displays. Multilayer transparent electrodes, having a much lower electrical resistance than widely-used transparent conducting oxide electrodes, were prepared by using RF/DC magnetron sputtering system. The multilayer structure consisted of three layers, [NiInZnO(NIZO)/Ag/NIZO]. The optical and electrical properties of the multilayered NIZO/Ag/NIZO structure were investigated in relation to the thickness of each layer. The optical and electrical characteristics of multilayer structures have been investigated as a function of the Ag and NIZO film thickness. High-quality transparent conductive films have been obtained, with sheet resistance of $9.8{\Omega}/sq$ for Ag film thickness of 8 nm. Also the multilayer films of inserted Ag 8 nm thickness showed a high optical transmittance above 93% in the visible range. The electrical and optical properties of the new multilayer films were mainly dependent on the thickness of Ag insertion layer.

• Tribology and Lubricants
• /
• 제20권5호
• /
• pp.237-244
• /
• 2004

Micro/nano tribological characteristics of PTFE coating films were experimentally studied. PTFE (polytetrafluoroethylene) modified polyethylene and low molecular weight PTFE were used as a coating materials. These films were deposited on Si-wafer (100) by IBAD (ion beam assisted deposition) method. The Ar ion beam sputtering was performed to change the surface topography of films using a hollow cathode ion gun under different Ar ion dose conditions in a vacuum chamber. Micro/nano tribological characteristics, water wetting angles and roughness were measured with a micro tribotester, SPM (scanning probe microscope), contact anglemeter and profilometer, respectively. The durability of the films were measured with macro tribotester. Results showed that the PTFE coating surfaces were converted to hydrophobic. The water contact angle of coated surfaces and surface roughness increased with the coating thickness. Adhesion and friction in micro and nano scale were governed by magnitude of normal load in soft material such as PTFE films. As the increase of sputtering time on low molecular weight PTFE films, the surface roughness was increased and nano adhesion and friction were decreased. The nano tribological characteristics of surfaces are mainly improved by chemical modification such as PTFE coating and given a synergy effect by the physical modification such as topographic modification.

• 센서학회지
• /
• 제17권3호
• /
• pp.178-182
• /
• 2008

Planar type micro catalytic combustible gas sensor was developed by using nano crystalline $SnO_2$ Pt thin film as micro heater was deposited by thermal evaporation method on the alumina substrate. The thickness of the Pt heater was around 160 nm. The sensor showed high reliability with prominent selectivity against various gases(Co, $C_3H_8,\;CH_4$) at low operating temperature($156^{\circ}C$). The sensor with nano crystalline $SnO_2$ showed higher sensitivity than that without nano crystalline $SnO_2$. This can be explained by more active adsorption and oxidation of hydrogen by nano crystalline $SnO_2$ particles. The present planar-type catalytic combustible hydrogen sensor with nano crystalline $SnO_2$ is a good candidate for detection of hydrogen leaks.

• 제어로봇시스템학회논문지
• /
• 제14권5호
• /
• pp.420-425
• /
• 2008

PMMA light guiding plate with nano-sized pattern was fabricated using anodized aluminum oxide membrane as a template for nano imprint lithography. Nano-sized pore arrays were prepared by the self-organization processes of the anodic oxidation using the aluminum plate with 99.999% purity. Since the aluminum plate has a rough surface, the aluminum plate with thickness of 1mm was anodized after the pre-treatments of chemical polishing, and electrochemical polishing. The surface morphology of the alumina obtained by the first anodization process was controlled by the concentration of electrochemical solution during the first anodization. The surface morphology of the alumina was also changed according to temperature of the solution during chemical polishing performed after first anodization. The pore widening process was employed for obtaining the one-channel with flat surface and height of the channel because the pores of the alumina membrane prepared by the fixed voltage method shows the structure of two-channel with rough surface. It is shown from SPM results that the nano-sized pattern on PMMA light guiding plate fabricated by nano imprint lithography method was well transferred from that of anodized aluminum oxide template.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2008년도 추계학술대회A
• /
• pp.1563-1565
• /
• 2008

Hydrophobic plastic plates employing nano surface features are injection molded using thermoplastic materials. A variotherm molding process is devised for filling the nano pores and releasing the molded nano features from the master. The size of the molded nano surface features are about 100nm in diameter and 200nm in height. The size of the molded plate is about 30mm x 30mm and the thickness is 1mm. As molding materials, Polypropylene, PMMA, COC and PC are employed, which are all typical commodity thermoplastic materials. The mold temperature(stamper temperature) is investigated as a major processing parameter for molding high aspect ratio nano surface features. Almost fully molded nano features are fabricated above a certain level of mold temperature depends on the employing material. The contact angles on the injection molded plates are measured to estimate the hydrophobicity and found to have higher contact angle up to 180% compared to the blank plate with no surface features.

• Structural Engineering and Mechanics
• /
• 제55권5호
• /
• pp.1001-1014
• /
• 2015

Bending analysis of functionally graded (FG) nano-plates is investigated in the present work based on a new sinusoidal shear deformation theory. The theory accounts for sinusoidal distribution of transverse shear stress, and satisfies the free transverse shear stress conditions on the top and bottom surfaces of the plate without using shear correction factor. The material properties of nano-plate are assumed to vary according to power law distribution of the volume fraction of the constituents. The size effects are considered based on Eringen's nonlocal theory. Governing equations are derived using energy method and Hamilton's principle. The closed-form solutions of simply supported nano-plates are obtained and the results are compared with those of first-order shear deformation theory and higher-order shear deformation theory. The effects of different parameters such as nano-plate length and thickness, elastic foundation, orientation of foundation orthtotropy direction and nonlocal parameters are shown in dimensionless displacement of system. It can be found that with increasing nonlocal parameter, the dimensionless displacement of nano-plate increases.

• Advances in nano research
• /
• 제5권4호
• /
• pp.337-357
• /
• 2017

Knowledge of thin films mechanical properties is strongly associated to the reliability and the performances of Nano Electro Mechanical Systems (NEMS). In the literature, there are several methods for micro materials characterization. Bulge test is an established nondestructive technique for studying the mechanical properties of thin films. This study improve the performances of NEMS by investigating the mechanical behavior of Nano rectangular thin film (NRTF) made of new material embedded in Nano Electro Mechanical Systems (NEMS) by developing the bulge test technique. The NRTF built from adhesively-bonded layers of basalt fiber reinforced polymer (BFRP) laminate composite materials in Nano size at room temperature and were used for plane-strain bulging. The NRTF is first pre-stressed to ensure that is no initial deflection before applied the loads on NRTF and then clamped between two plates. A differential pressure is applying to a deformation of the laminated composite NRTF. This makes the plane-strain bulge test idea for studying the mechanical behavior of laminated composite NRTF in both the elastic and plastic regimes. An exact solution of governing equations for symmetric cross-ply BFRP laminated composite NRTF was established with taking in-to account the effect of the residual strength from pre-stressed loading. The stress-strain relationship of the BFRP laminated composite NRTF was determined by hydraulic bulging test. The NRTF thickness gradation in different points of hemisphere formed in bulge test was analysed.

• Wind and Structures
• /
• 제32권1호
• /
• pp.31-46
• /
• 2021

The current research deals with, stability/instability and cylindrical composite nano-scaled shell's resonance frequency filled by graphene nanoplatelets (GPLs) under various thermal conditions (linear and nonlinear thermal loadings). The piece-wise GPL-reinforced composites' material properties change through the orientation of cylindrical nano-sized shell's thickness as the temperature changes. Moreover, in order to model all layers' efficient material properties, nanomechanical model of Halpin-Tsai has been applied. A functionally modified couple stress model (FMCS) has been employed to simulate GPLRC nano-sized shell's size dependency. It is firstly investigated that reaching the relative frequency's percentage to 30% would lead to thermal buckling. The current study's originality is in considering the multifarious influences of GPLRC and thermal loading along with FMCS on GPLRC nano-scaled shell's resonance frequencies, relative frequency, dynamic deflection, and thermal buckling. Furthermore, Hamilton's principle is applied to achieve boundary conditions (BCs) and governing motion equations, while the mentioned equations are solved using an analytical approach. The outcomes reveal that a range of distributions in temperature and other mechanical and configurational characteristics have an essential contribution in GPLRC cylindrical nano-scaled shell's relative frequency change, resonance frequency, stability/instability, and dynamic deflection. The current study's outcomes are practical assumptions for materials science designing, nano-mechanical, and micromechanical systems such as micro-sized sensors and actuators.

• Elastomers and Composites
• /
• 제51권4호
• /
• pp.342-349
• /
• 2016

Characteristics of the swelling-induced wrinkles on the surfaces of natural rubber (NR) film were investigated. The wrinkle structure was generated by swelling of NR film pre-stretched and firmly bonded onto an aluminum substrate in hexane. A novel experimental method was adopted to replicate the swelling-induced wrinkles on the NR film using an epoxy-hardener system. To get insight into the wrinkle parameters; the wrinkle length (L), wrinkle distance (D), wrinkle height (H) and the angle between two consecutive wrinkles (${\theta}$), the cross-sections of the replicas obtained from saturated swollen NR film were examined using an optical microscopy (OM). From the OM images, the wrinkling parameters were measured as a function of the thickness of NR film from 0.42 to 1.76 mm. Also, it was evaluated that the effects of swelling time on the wrinkling parameters. The length (L), distance (D) and height (H) of wrinkles increased as the thickness of the NR film and the swelling time increased. However, the angle between the wrinkles (${\theta}$) showed a sharp decrease up to a swelling time of 200 minutes and slightly decreased afterwards.