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Temperature Effect on the Growth Rate and Physical Characteristics of SnO2 Thin Films Grown by Atomic Layer Deposition

Kim D., Kim D. H., Riu D.-H., Choi B. J.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 2

1061--1064

EN

Among the various thin film coating techniques, atomic layer deposition (ALD) has features of good controllability of the thickness, excellent step-coverage in 3-dimensional object even in the sub-nm thickness range at the relatively low deposition temperature. In this study, SnO2 thin films were grown by ALD in the variation of substrate temperatures from 150 to 250°C. Even such a low temperature may influence on the growth kinetics of the ALD reaction and thus the physical characteristics of thin films, such as crystallinity, film density and optical band gap, etc. We observed the decrease of the growth rate with increasing substrate temperature, at the same time, the density of the film was decreased with increasing temperature. Steric hindrance effect of the precursor molecule was attributed to the inverse relationship of the growth temperature and growth rate as well as the film density. Optical indirect band gap energy (~3.6 eV) of the ALD-grown amorphous SnO2 films grown at 150°C was similar with that of the literature value, while slightly lower band gap energy (~3.4 eV) was acquired at the films grown at higher temperature.

2

Synthesis Of SiC/Cu Composite Powders From Polycarbosilane And Cupric Nitrate Trihydrate

Bang R.-S., Yim D.-M., Riu D.-H., Oh S.-T.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 2B

1261--1263

EN

SiC/Cu composite powders with the barrier coating of SiC-Al onto SiC powders were synthesized from Al-containing polycarbosilane precursor and Cu-nitrate hydrate. Curing at 200°C and high temperature pyrolysis at 1600°C was used to achieve the crystallization of precursor, forming the SiC-Al coating on the surface of SiC powders. A core-shell structure with the core of SiC and the shell of Cu was constructed by calcination and hydrogen-reduction of Cu nitrate hydrate. XRD and SEM analysis revealed that the β-SiC and 4H-SiC phases were formed on the surface of the initial α-SiC powders. Also, it was observed by EDX mapping that core powders of SiC were homogeneously surrounded with the fine Cu particles on their surface.

3

Improved Photovoltaic Properties Of Dye-Sensitized Solar Cells Using Laser Patterned F-Doped SnO2 Thin Films

An H.-R., An H., Riu D.-H., Ahn H. J.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 2B

1241--1245

EN

We modified the surfaces of F-doped SnO2 thin films using laser patterning to improve the photovoltaic properties of dye-sensitized solar cells. To do so, we varied the laser power density and the distance between laser-patterned lines. First, we investigated three power densities. Higher densities led to higher sheet resistances owing to increases in surface roughnesses. The lowest power density increased surface roughness without electrical degradation. Next, we explored three line spacings at a fixed power density. The films with the narrowest spacing exhibited the highest power conversion efficiency (~7.00%), the highest short-circuit photocurrent density (16.28 mA/cm2), and a good fill factor (58.82%).