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Structural, Electrical, and Optical Properties of ZnO Films Grown by Atomic Layer Deposition at Low Temperature

Park Ji-Young, Weon Ye Bin, Jung Myeong Jun, Choi Byung Joon

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 4

1503--1506

EN

Zinc oxide (ZnO) is a prominent n-type semiconductor material used in optoelectronic devices owing to the wide bandgap and transparency. The low-temperature growth of ZnO thin films expands diverse applications, such as growth on glass and organic materials, and it is also cost effective. However, the optical and electrical properties of ZnO films grown at low temperatures may be inferior owing to their low crystallinity and impurities. In this study, ZnO thin films were prepared by atomic layer deposition on SiO2 and glass substrates in the temperature range of 46-141℃. All films had a hexagonal würtzite structure. The carrier concentration and electrical conductivity were also investigated. The low-temperature grown films showed similar carrier concentration (a few 1019 cm-3 at 141°C), but possessed lower electrical conductivity compared to high-temperature (>200°C) grown films. The optical transmittance of 20 nm thin ZnO film reached approximately 90% under visible light irradiation. Additionally, bandgap energies in the range of 3.23-3.28 eV were determined from the Tauc plot. Overall, the optical properties were comparable to those of ZnO films grown at high temperature.

2

Growth Temperature Effect of Atomic-Layer-Deposited GdOx Films

Ryu Sung Yeon, Yun Hee Ju, Lee Min Hwan, Choi Byung Joon

Archives of Metallurgy and Materials

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2021

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Vol. 66, iss. 3

755--758

EN

Gadolinium oxide (Gd2O3) is one of the lanthanide rare-earth oxides, which has been extensively studied due to its versatile functionalities, such as a high permittivity, reactivity with moisture, and ionic conductivity, etc. In this work, GdOx thin film was grown by atomic layer deposition using cyclopentadienyl (Cp)-based Gd precursor and water. As-grown GdOx film was amorphous and had a sub-stoichiometric (x ~ 1.2) composition with a uniform elemental depth profile. ~3 nm-thick GdOx thin film could modify the hydrophilic Si substrate into hydrophobic surface with water wetting angle of 70°. Wetting and electrical test revealed that the growth temperature affects the hydrophobicity and electrical strength of the as-grown GdOx film.

3

Electrical Characteristics of Tin Oxide Films Grown by Thermal Atomic Layer Deposition

Yoon Seong Yu, Choi Byung Joon

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 3

1041--1044

EN

Tin dioxide (SnO2 ) is an n-type semiconductor and has useful characteristics of high transmittance, excellent electrical properties, and chemical stability. Accordingly, it is widely used in a variety of fields, such as a gas sensor, photocatalyst, optoelectronics, and solar cell. In this study, SnO2 films are deposited by thermal atomic layer deposition (ALD) at 180°C using Tetrakis(dimethylamino)tin and water. A couple of 5.9, 7.4 and 10.1nm-thick SnO2 films are grown on SiO2 /Si substrate and then each film is annealed at 400°C in oxygen atmosphere. Current transport of SnO2 films are analyzed by measuring current – voltage characteristics from room temperature to 150°C. It is concluded that electrical property of SnO2 film is concurrently affected by its semiconducting nature and oxidative adsorption on the surface.

4

Dilatometric Analysis of the Sintering Behavior of Bi2Te3 Thermoelectric Powders

Han Ju-Yeon, Byun Jong Min, Lee Young-In, Choi Byung Joon, Kim Hogyoung, Oh Sung-Tag

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 3

1117--1120

EN

The sintering behavior of p-type bismuth telluride powder is investigated by means of dilatometric analysis. The alloy powders, prepared by ball milling of melt-spun ribbons, exhibit refined and flake shape. Differential thermal analysis reveals that the endothermic peak at about 280°C corresponds to the melting of bismuth, and peaks existing between 410°C and 510°C are presumably due to the oxidation and crystallization of the powder. The shrinkage behavior of ball-milled powders was strongly dependent of heating rate by the thermal effect exerted on specimens. In the case of 2°C/min, the peak temperature for the densification is measured at 406°C, while the peak temperature at a heating rate of 20°C/min is approximately 443°C. The relative density of specimen pressureless-sintered at 500°C exhibited relatively low value, and thus further study is required in order to increase the density of sintered body.