• KIEE International Transactions on Electrophysics and Applications
• /
• 제5C권3호
• /
• pp.111-114
• /
• 2005

Organic monolayers were fabricated onto Au(l l l) substrate by self-assembly method using dipyridinium. Also, organic single molecule in the organic monolayers was selected to measure the current-voltage (I-V) curves by using the ultrahigh vacuum scanning tunneling microscopy (UHV-STM). The organic molecule used in the experiment was dipyridinium dithioacetate, which contains thiol functional group and can be self-assembled easily onto Au(l l l) substrate. The concentration of dipyridinium dithioacetate for self-assembly procedure was I [mM/L]. To confirm the formation of self-assembled mono layers (SAMs), the differences of thickness of the self-assembled organic monolayers were observed by using an ellipsometer, and the morphology and I-V curves of the SAMs were investigated by using UHV-STM. The applied voltages were from -2 [V] to +2 [V], temperature was 300 [K]. The vacuum for measuring current of the organic single molecule was 6 $\times$ 10$^{-8}$ [Torr]. As a result, properties of the negative differential resistance (NDR) in constant voltage were found.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
• /
• pp.395-396
• /
• 2005

We fabricated self-assembled monolayers(SAMs) onto quartz crystal microbalance(QCM) using viologen, which has been widely used as electron acceptor and electron transfer mediator. We determined the time dependence to resonant frequency shift during self-assembly process and observed the morphology of self-assembled mono layers by STM and investigated the electrochemical behavior of SAMs by cyclic voltammetry. Electrochemical deposition of viologen was investigated using electrochemical quartz crystal microbalance(EQCM). The redox reactions of viologen were highly reversible and the EQCM has been employed to monitor the electrochemically induced adsorption of SAMs during the redox reactions.

• 한국고분자학회지:고분자과학과기술
• /
• 제15권3호
• /
• pp.286-295
• /
• 2004

자기조립 단분자막 (self-assembled monolayers, SAMs)은 주어진 기질의 표면에 자발적으로 입혀진 규칙적으로 잘 정렬된 유기 분자막이다 (그림 1). SAMs의 제조에 이용되는 계면 활성제 분자는 그림 2에서 보여주듯이 세 개의 부분으로 이루어져 있다. 먼저 기질과 결합하는 머리 부분의 반응기, 규칙적인 분자 막 형성을 가능하게 하는 몸통 부분의 긴 알칸사슬, 그리고 분자 막의 기능을 좌우하는 꼬리 부분의 작용기로 나누어진다. 가장 간단한 작용기로는 알킬 그룹이 있으나 분자 막에 특수한 기능을 부여하기 위해서는 여러 가지 다른 그룹들 (예:NH$_2$, OH, COOH 등)이 이용되고 있다. (중략)

• Bulletin of the Korean Chemical Society
• /
• 제28권12호
• /
• pp.2445-2448
• /
• 2007

Self-assembled monolayers (SAMs) were formed by adsorption of thioacetyl-terminated tolanethioacetate (TTA) on Au(111) in a 0.5-mM ethanol solution after one day immersion at room temperature. Molecular-scale STM imaging revealed that the TTA SAMs were composed of two mixed phases; an ordered phase with small domains describing a ( × 2 )R30° structure and a disordered phase. Interestingly, after annealing the precovered TTA SAMs on Au(111) at 90 °C for 1 h, the small ordered domains grew unidirectionally, resulting in the formation of unique rod-like domains, which were assigned a ( × 2 )R7° structure. These results will be very useful in understanding the formation and thermal behavior of TTA SAMs on gold surfaces.

• Journal of Electrochemical Science and Technology
• /
• 제10권2호
• /
• pp.170-176
• /
• 2019

Alkanethiol self-assembled monolayers (SAMs) and partially ferrocene (Fc) modifications were applied to the Au ultramicroelectrode (UME) rather than to standard sized electrodes with dimension of millimeters. The electron transfer mediation of the SAMs and Fc modified Au UME was investigated by using a p-aminophenol (p-AP) oxidation reaction via cyclic voltammetry. The electrocatalytic p-AP oxidation at the SAMs and Fc modified Au UME showed a much larger electrocatalytic current density than that at the standard sized electrode due to the fast mass transfer rate at the UME.

• Bulletin of the Korean Chemical Society
• /
• 제35권2호
• /
• pp.601-604
• /
• 2014

Two classes of morpholino-substitued thioacetate have been successfully synthesized and their electrochemical properties of self-assembled monolayers (SAMs) on Au electrode are measured by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The barrier property of the SAMs-modified surfaces is evaluated by using potassium ferro/ferri cyanide. The results suggest that the arenethioacetate forms higher-quality close-packed blocking monolayers in comparison with alkanethioacetate. Furthermore, it has shown that the barrier properties of these monolayers can be significantly improved by mixed SAMs formation with decanethiol. From our experimental results we find that the electron transfer reaction of $[Fe(CN)_6]^{3/4-}$ redox couple occurs predominantly through the pinholes and defects present in the SAM and both SAMs show a good and fast capacity in recognition for $Ag^+$. The morphological and elementary composition have also been examined by scanning electron microscope (SEM) and energy dispersive spectrometer (EDS).

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2003년도 춘계학술대회 논문집
• /
• pp.219-222
• /
• 2003

Self-Assembled Monolayers(SAMs) by alkanethiol adsorption to thin metal film are widely being investigated for applications as coating layer for anti-stiction or friction reduction and in fabrication of micro structure of molecular and bio molecular. Recently, there have been many researches on micro patterning using the advantages of very thin thickness and etching resistance in selective etching of thin metal film of Self- Assembled Monolayers. In this report, we present the micromachining thin metal film by Mask-Less laser patterning of alknanethiolate Self-Assembled Monolayers.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
• /
• pp.243-243
• /
• 2012

Self-assembled monolayers (SAMs) prepared by aromatic thiols on gold surfaces have much larger potential for electronic device applications due to their electronic properties. In this study, the formation and structures of SAMs prepared by benzenethiol (BT), toluenethiol (TT), 2-fluorobenzenethiol (2-FBT), 3-fluorobenzenethiol (3-FBT), 4-fluorobenzenethiol (4-FBT), 4-chlorobenzenethiol (4-CBT), 4-fluorobenzenemethanethiol (4-FBMT), and 4-chlorobenzenemethanethiol (4-CBMT) on Au(111) were examined using scanning tunneling microscopy (STM) and Kelvin probe (KP) to explore the structure and electronic interface properties of eight differently substituted aromatic thiol SAMs on Au(111). And these values are compared with gas phase dipole moments computed by quantum chemical calculations for individual thiol molecules. It was revealed that all eight thiol-molecules form uniform SAMs on Au(111) at $75^{\circ}C$ compared to lower solution temperature by STM observation. The work function change obtained in the KP measurements and calculated molecular dipole moments have the linear relationship while the 4-FBMT and 4-CBMT deviate from this tendency.

• Bulletin of the Korean Chemical Society
• /
• 제32권4호
• /
• pp.1253-1257
• /
• 2011

The surface structures, adsorption conditions, and thermal desorption behaviors of cyclopentanethiol (CPT) self-assembled monolayers (SAMs) on Au(111) were investigated by scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and thermal desorption spectroscopy (TDS). STM imaging revealed that although the adsorption of CPT on Au(111) at room temperature generates disordered SAMs, CPT molecules at $50^{\circ}C$ formed well-ordered SAMs with a $(2{\surd}3{\times}{\surd}5)R41^{\circ}$ packing structure. XPS measurements showed that CPT SAMs at room temperature were formed via chemical reactions between the sulfur atoms and gold surfaces. TDS measurements showed two dominant TD peaks for the decomposed fragments ($C_5H_9^+$, m/e = 69) generated via C-S bond cleavage and the parent molecular species ($C_5H_9SH^+$, m/e = 102) derived from a recombination of the chemisorbed thiolates and hydrogen atoms near 440 K. Interestingly, dimerization of sulfur atoms in n-alkanethiol SAMs usually occurs during thermal desorption and the same reaction did not happen for CPT SAMs, which may be due to the steric hindrance of cyclic rings of the CPT molecules. In this study, we demonstrated that the alicyclic ring of organic thiols strongly affected the surface structure and thermal desorption behavior of SAMs, thus providing a good method for controlling chemical and physical properties of organic thiol SAMs.

• International Journal of Precision Engineering and Manufacturing
• /
• 제7권1호
• /
• pp.13-17
• /
• 2006

Self-Assembled Monolayers (SAMs) formed by alkanethiol adsorption to thin metal film are widely being investigated for applications as coating layer for anti-stiction or friction reduction and in fabrication of micro structure of molecules and bio molecules. Recently, there have been many researches on micro patterning using the advantages of very thin thickness and etching resistance of Self-Assembled Monolayers in selective etching of thin metal film. In this report, we present the several machining method to form the nanoscale structure by Mask-Less laser patterning using alknanethiolate Self-Assembled Monolayers such as thin metal film etching and heterogeneous SAM structure formation.