• Transactions on Electrical and Electronic Materials
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• v.12 no.4
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• pp.164-168
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• 2011

Nanocrystalline cadmium sulphide (CdS) thin films were prepared using chemical bath deposition (CBD), and the structural, optical and photoconductive properties were investigated. The crystal structure of CdS thin film was studied by X-ray diffraction. The crystallite size, dislocation density and lattice constant of CBD CdS thin films were investigated. The dislocation density of CdS thin films initially decreases with increasing film thickness, and it is nearly constant over the thickness of 2,500 ${\AA}$. The dislocation density decreases with increasing the crystallite size. The Urbach energies of CdS thin films are obtained by fitting the optical absorption coefficient. The optical band gap of CdS thin films increases and finally saturates with increasing the lattice constant. The Urbach energy and optical band gap of the 2,900 A-thick CdS thin film prepared for 60 minutes are 0.24 eV and 2.83 eV, respectively. The activation energies of the 2,900 ${\AA}$-thick CdS thin film at low and high temperature regions were 14 meV and 31 meV, respectively. It is considered that these activation energies correspond to donor levels associated with shallow traps or surface states of CdS thin film. Also, the value of ${\gamma}$ was obtained from the light transfer characteristic of CdS thin film. The value of ${\gamma}$ for the 2,900 A-thick CdS thin film was 1 at 10 V, and it saturates with increasing the applied voltage.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2003.11a
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• pp.368-376
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• 2003

In this research, DLC thin films are produced as several hundred nm thickness by PE-CVD method. And then these thin films are estimated tribological characteristics to find out useful possibilities as a protecting film for high-quality function and life extension at MEMs by mechanical properties observation . These are measured thickness and residual stress of DLC coating. Compared after measuring friction coefficient, adhesion force, hardness, cohesive force of coating films. As results all test, we can decide several conclusions. First, friction coefficient decreased, as the load increased. otherwise, friction coefficient increased, as thickness of coating film increased under low load$(1\~50mN)$. Secod, adhesion force increased as thickness of coating films. Third, hardness of coating film is affected by substrate coating film when it is less than thickness of 300nm and it has general hardness of DLC coating film when it is more than thickness of 500nm. Fourth, cohesive force of coating film is complexly affected by hardness, adhesion force, residual stress, etc.

• Journal of the Korean Vacuum Society
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• v.8 no.3A
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• pp.231-237
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• 1999

$SrBi_{22.4}Ta_2O_9$ (SBT) thin films of 70~150 nm thickness were prepared on platinized silicon substrates by Liquid Source Misted Chemical Deposition (LSMCD) process, and their microstructure, feroelectric and leakage current characteristics were investigated. By annealing at $800^{\circ}C$ for 1 hour in oxygen ambient, SBT films were fully crystallized to the Bi layered perovskite structure without preferred orientation. The grain size of the LSMCD- derived SBT films was about 100nm, and was not varied with the film thickness. $2P_r$ and $E_c$ of the SBT films increased with decreasing the film thickness, and the 70nm-thick SBT film exhibited $2P_r$ of 17.8 $\mu$C/$\textrm{cm}^2$ and $E_c$ of 74kV/cm at applied voltage of 5V. Within the film thickness range of 70~150nm, the relative dielectric permittivity of the LSMCD-derived SBT film decreased with decreasing the film thickness. Leakage current densities lower than $10^{-7}\textrm{A/cm}^2$ at 5V were observed in the SBT films thicker than 125nm.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.1856-1858
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• 2005

In this study, Indium Tin Oxide(ITO) thin films were prepared at $O_2$ gas 0.2 sccm, no heating to substrate and working pressure 1mTorr with varying deposition time. We estimated structural, optical, electrical characteristics of ITO thin films as function of ITO thin films thickness. As a result, XRD peaks increased with increasing the thickness. The ITO thin film was fabricated with resistivity $4.23{\times}10^{-4}[{\Omega}{\cdot}cm]$, carrier mobility $52.9[cm^2/V{\cdot}sec]$, carrier concentration $2.79{\times}10^{20}[cm^{-3}]$. And we also observed that the SEM images of ITO thin films surface.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.1049-1052
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• 2003

This study shows the change of the structural characteristic of AIN thin film deposition with the change of the deposition conditions such as Ar/$N_2$ gas ratio, operating pressure in chamber, and the distance between substrate and target in RF Magnetron Sputtering. The orientation and surface roughness of AIN thin film are studied by using XRD and AFM and the thickness is measured by using STYLUS PROFILER. While we can not identify the orientation of the thin film deposited in Ar only, we can obtain the (100) orientation of the thin film with the addition of $N_2$ to Ar. Especially the thin film deposited at 10% of Ar/$N_2$ gas ratio appears to be the most (100) oriented. The (100) orientation of thin film becomes weaker as the operating pressure becomes higher. The further distance between substrate and target is stronger the (100) orientation of the thin film is. The (100) orientation becomes weaker and (002) orientation starts to appear as the distance is shorter.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.400-403
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• 2012

$Cu_2ZnSnSe_4$(CZTSe) is emerged as a promising material for thin-film solar cells because of non-toxic, inexpensive and earth abundant more than $Cu(In,Ga)Se_2$ materials. For fabricating compound semiconductor thin-film solar cells, CdS is widely used for a buffer layer which fabricated by a chemical bath deposition method (CBD). Through the experiment, we controlled deposition temperature and mol ratio of solution conditions to find the proper grain 크기 and exact composition. The optimum CdS layers were characterized in terms of surface morphology by using a scanning electron microscope (SEM) and atomic force microscope (AFM). The optimized CdS layer process was applied on CZTSe thin-films. The thickness of buffer layer related with device performance of solar cells which controlled by deposition time. Local surface potential of CdS/CZTSe thin-films was investigated by Kelvin probe force microscopy (KPFM). From these results, we can deduce local electric properties with different thickness of buffer layer on CZTSe thin-films. Therefore, we investigated the effect of CdS buffer layer thickness on the CZTSe thin-films for decreasing device losses. From this study, we can suggest buffer layer thickness which contributes to efficiencies and device performance of CZTSe thin-film solar cells.

• Journal of the Korean Ceramic Society
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• v.25 no.4
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• pp.341-348
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• 1988

Thin films of tin-oxide were prepared by chemical vapor deposition technique using the direct of SnCl4. Resistivity and carrier concentration of deposited SnO2 thin film were measured by 4-point probe method and Hall effect measurement. The results showed the remarkable dependence of electrical properties on the deposition temperature. As the deposition temperature increased, resistivity of deposited film initially decreased to a minimum value of ~10-3$\Omega$cm at 50$0^{\circ}C$, and then rapidly increased to ~10$\Omega$cm at $700^{\circ}C$. Electrical conductance of these films was measured in exposure to H2 gas. It was found that gas sensitivity was affected combination of film thickness and intrinsic resistivity of deposited film. Gas sensitivity increased with decrease of film thickness. Fairly high sensitivity to H2 gas was obtained for the film deposited at $700^{\circ}C$. Optimum operation temperature of sensing was 30$0^{\circ}C$ for H2 gas.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.1
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• pp.49-52
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• 2008

To study the optical transmittance through nickel thin films with various thicknesses. Methods: We measured the optical transmittance through thin nickel film with various thicknesses. Results: The thickness dependence of the optical transmittance through nickel thin films deposited by thermal evaporation had been investigated. The optical transmittance rapidly decreased with the Ni film thickness less than 70 nm while it slightly decreased with the thickness more than 70 nm. In the experiment of optical dispersion, most of the light transmitted in the incidence direction. The result of experiment showed that optical dispersion was negligibly. Conclusions: Optical transmittance exponentially decreased as nickel thin film thickness increased.

• Korean Journal of Optics and Photonics
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• v.33 no.4
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• pp.159-166
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• 2022

We measured the thickness and refractive index of a thin film using a double-slit diffraction experiment. The amount of phase step in the transmitted light generated by the thin film on the transparent substrate was measured by analyzing the diffraction pattern from the double slits. Experiments were conducted not only in air but also in distilled water, to determine thickness and refractive index simultaneously. To verify the validity of this method, we compared our values for thickness and refractive index to those measured using the well-established waveguide-coupling method. The suggested method is expected to be applied as a new method to simultaneously measure the thickness and refractive index of thin films, along with existing methods.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.05a
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• pp.103-107
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• 1994

An experimental study was carried out to investigate the fabrication process and electrical breakdown of electrodeposted polyimide film from nonaqueous emulsion onto metal electrode surface. The thickness of imide film control led by the deposition voltage and time are proportional to the voltage or time. From the results, yeilds is proportional to the total elctrical charge flow through the electrode. When electrophoretic deposition voltage is 30 [V] deposition time is 30 sec, 40 sec, 50 sec, then the thickness of the films are 2.13 $\mu\textrm{m}$, 2.69 $\mu\textrm{m}$, 3.16 $\mu\textrm{m}$, 3.94 $\mu\textrm{m}$, respectively Electrical breakdown voltage of polyimide thin film shows very high. As film thicknes increase, the breakdown voltage are increased, but are net directly proprotional to thickness of the film.