• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05b
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• pp.55-61
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• 2002

Ultra-fine particles of $SnO_{2}$ was synthersized by the sol-gel powder processing using tin(II) chloride dihydrate$(SnCl_{2}{\cdot}2H_{2}O)$ and ethanol$(C_{2}H_{5}OH)$ as raw materials. Gel powders can be obtained by drying of sol at $120^{\circ}C$ after aging 72hrs and 168hrs. The amount of $SnO_{2}$ phase was increased with temperature because of the evaporation of volatile components, and the creation of $SnO_{2}$ phase was almost done by the heat treatment at $700^{\circ}C/30min$ The grain sizes after firing are about 20-30nm, and it showed the narrow distribution of grain size. The specimens to measure electrical properties were fabricated by the thick film screen printing technique on the alumina substrates. The conductance of $SnO_{2}$ was increased with temperature up to $380^{\circ}C$ by the typical conduction mechanism of semiconducting ceramics. There was a region of constant conductance between about $200^{\circ}C$ and $380^{\circ}C$ due to the increment of electron concentration with temperature and the annihilation of conduction carriers by the absorption and electron trapped-ionization of oxygen on the surface of $SnO_{2}$, It was finally showed the intrinsic behaviors above $450^{\circ}C$. The sensing properties of response time, recovery, and sensitivity of CO were improved with aging time.

• Journal of the Korean Vacuum Society
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• v.1 no.1
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• pp.126-133
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• 1992

This study deals with the crystal growth and the optical characteristics of CdS thin films activatedby silver. CdS:Ag thin films were deposited by using an electron beam evaporation(EBE) technique in vacuumof 1.5X 10-'torr, voltage of 4 kV, current of 2.5 mA and substrate temperature of 250$^{\circ}$C CdS:Ag photoconductivefilms prepared by EBE method show high photoconductivity after annealing at about 550"c for 0.5 h in air andAr gas.The grain size of CdS:Ag thin films annealed in Ar atmosphere (1 atm) was grown over 1 ym and the thicknessof the films is 4-5 pm. The analysis of X-ray diffraction patterns shows that the crystal structures are hexagonal.The diffraction line by (00.2) plane can only be observed, indicating that c-axis of hexagonal grows preferentiallyperpendicular to the substrate. The profiles of photoluminescence spectra of CdS:Ag films show Gaussian typecurves at room temperature, the maximum peak spectral sensitivity of CdS:Ag is located at the wavelength of520 nm.We annealed CdS:Ag thin films in air and Ar vapor in order to make the CdS photoconductors having theintensive photocurrent, the broad distribution of the photocurrent spectrum and the large value of the ratioof the photocurrent (pc) to the dark current(dc). We found that CdS:Ag thin films annealed in air atmospherewas the best one.air atmosphere was the best one.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.159-159
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• 2011

Among the semiconductor ternary compounds in the I-III-$VI_2$ series, $CulnS_2$ ($CulnSe_2$) are one of the promising materials for photovoltaic applications because of the suitability of their electrical and optical properties. The $CuInS_2$ thin film is one of I-III-$VI_2$ type semiconductors, which crystallizes in the chalcopyrite structure. Its direct band gap of 1.5 eV, high absorption coefficient and environmental viewpoint that $CuInS_2$ does not contain any toxic constituents make it suitable for terrestrial photovoltaic applications. A variety of techniques have been applied to deposit $CuInS_2$ thin films, such as single/double source evaporation, coevaporation, rf sputtering, chemical vapor deposition and chemical spray pyrolysis. This is the first report that $CuInS_2$ thin films have been prepared by Aerosol Jet Deposition (AJD) technique which is a novel and attractive method because thin films with high deposition rate can be grown at very low cost. In this study, $CuInS_2$ thin films have been prepared by Aerosol Jet Deposition (AJD) method which employs a nozzle expansion. The mixed fluid is expanded through the nozzle into the chamber evacuated in a lower pressure to deposit $CuInS_2$ films on Mo coated glass substrate. In this AJD system, the characteristics of $CuInS_2$ films are dependent on various deposition parameters, such as compositional ratio of precursor solution, flow rate of carrier gas, stagnation pressure, substrate temperature, nozzle shape, nozzle size and chamber pressure, etc. In this report, $CuInS_2$ thin films are deposited using the deposition parameters such as the compositional ratio of the precursor solution and the substrate temperature. The deposited $CuInS_2$ thin films will be analyzed in terms of deposition rate, crystal structure, and optical properties.