Structural, electrical, and optical properties of transparent conductive In2O3–SnO2 films

Satô, Yasushi; Tokumaru, Ryo; Nishimura, Eriko; Song, Pung Keun; Shigesato, Yuzo; Utsumi, K.; Iigusa, Hitoshi

doi:10.1116/1.1894421

Cited by 53 publications

(33 citation statements)

References 20 publications

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“…When a metal combines with oxygen to become a compound, its inner-shell electron binding energy increases slightly. 32 Therefore, we suggest that the shift of the In 3d binding energy of the films deposited by ULPS is caused by the increased formation of indium oxide phase in the films. The electronic-transport behavior of these films strongly depends on the number of oxygen vacancies that are generated and compensated.…”

Section: Resultsmentioning

confidence: 98%

Improving the Morphological and Optical Properties of Sputtered Indium Tin Oxide Thin Films by Adopting Ultralow-Pressure Sputtering

Huh

Yang

Song

et al. 2009

J. Electrochem. Soc.

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The morphological and optical properties of indium tin oxide ͑ITO͒ thin films deposited by an ultralow-pressure dc magnetron sputtering ͑ULPS͒ method followed by postannealing treatment at 250°C are reported. The surface roughness of the film ͑R rms : 0.5 nm͒ deposited using ULPS was about 5 times lower than that of the film ͑R rms : 2.7 nm͒ sputtered using a pressure of 6.7 ϫ 10 −1 Pa. ITO thin films with a low resistivity of 3.7 ϫ 10 −4 ⍀ cm were also achieved using a continuous two-step deposition process, in which the initial layer was deposited using ULPS and then the final layer was deposited with a SP of 6.7 ϫ 10 −1 Pa, without the use of any other additional steps. Both the ULPS and continuous two-step deposition methods were found to be effective for producing ITO thin films with enhanced morphologies that make them suitable for use in display devices.Indium tin oxide ͑ITO͒ thin films are highly degenerate, widebandgap semiconductors ͑E g : 3.4-4.3 eV͒. They have a low electrical resistivity due to their high carrier concentration, and the location of their Fermi level is above the lower edge of the conduction band. 1-3 ITO films also exhibit a high level of transmission in the visible near-infrared regions of the electromagnetic spectrum. Due to these unique properties, ITO thin films have been widely studied for their potential use in the optoelectronics industry and display devices, such as solar-control windshield glass, solar cells, organic light-emitting displays ͑OLEDs͒, flexible display devices, and transparent, flexible electronic circuit boards. [3][4][5] Smooth surface morphology with high electrical conductivity is the crucial factor for the current driven devices such as OLEDs. So far, several methods have been employed to prepare ITO thin films. Examples include spray pyrolysis, reactive evaporation, pulsed laser deposition, conventional magnetron sputtering, cesium-ion-induced magnetron sputtering, and ion-beam assisted sputtering. 6-11 Among these deposition methods, magnetron sputtering is preferable, because it allows easy process control for the device structure and the production of display devices with large areas. However, one of the practical drawbacks of using sputtered ITO thin films for display device applications is their rough surface morphology. This makes them unsuitable for use as the semiconducting layer or transparent electrode of display devices. For example, the quality of the interface between the ITO electrode and the organic emitting layer is crucial to the performance of OLEDs. 12-15 Using a rough ITO layer as the anode may cause undesired electrical shorts or decrease the contact area between the emitting layers and the anode and even form bubbles to deteriorate the color quality and lifetime of the emitting area. 12,16 These functional properties of ITO thin films are strongly dependent on their microstructures, which are influenced by the deposition method and processing conditions used to make them.In this study, ITO thin films with smooth surface morphologies w...

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Section: Resultsmentioning

confidence: 98%

Improving the Morphological and Optical Properties of Sputtered Indium Tin Oxide Thin Films by Adopting Ultralow-Pressure Sputtering

Huh

Yang

Song

et al. 2009

J. Electrochem. Soc.

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“…3 a flat valence-band top throughout the bilayer structure. In addition, since the work functions of SnO 2 and MgO are comparable, the Fermi level can be fitted [22,24], so that a possible conduction-band barrier at the hetero-junction can be neglected for simplicity. We also know that, in general, electrons are more mobile than holes in the oxide [25].…”

Section: Discussionmentioning

confidence: 99%

Ultraviolet-induced erasable photochromism in bilayer metal oxide films

Terakado

Tanaka

Nakazawa³

2011

Solid State Communications

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We demonstrate that optical transmittance of bilayer samples consisting of pyrolytically-coated amorphous Mg-Sn-O and metal-oxide films as In 2 O 3 and SnO 2 decreases upon ultraviolet illumination, which can be recovered by annealing in air at ~300˚C. Spectral, structural, and compositional studies suggest that this photochromic phenomenon is induced by photoelectronic excitation in the Mg-Sn-O film, electron injection into the metal oxide, which becomes negatively charged, and subsequent formation of metallic particles, which absorb and/or scatter visible light.

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“…The preparation processes of ITO thin films include spray [3], chemical vapor deposition (CVD) [4], evaporation [5] and magnetron sputtering [6]. Among these processes, the most preferred method in a production line is DC magnetron sputtering using ITO ceramic targets.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of IZSO films deposited by a co-sputtering system

et al. 2007

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In-Zn-Sn-O films were deposited on a polycarbonate (PC) substrate by a magnetron co-sputtering system using two cathodes (DC, RF) without substrate heating. Two types of ITO targets (target A: doped with 5 wt.% SnO2, target B: doped with 10 wt.% SnO2) were used as an In-Sn-O source. The ITO and ZnO targets were sputtered by DC and RF discharges, respectively, and the composition of the In-Zn-Sn-O films was controlled via the power ratio of each cathode. In the case of ITO target A, the lowest resistivity (4.3 × 10Ωcm) was obtained for the film deposited at the RF power (ZnO) of 55W. In the case of ITO target B, the lowest resistivity (2.9 × 10Ωcm) of the film was obtained at the RF power (ZnO) of 30W, which was attributed to the increase in carrier density. Hall mobility decreased with increasing carrier density, which could be explained by the increase in ionized impurity scattering.

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Structural, electrical, and optical properties of transparent conductive In2O3–SnO2 films

Cited by 53 publications

References 20 publications

Improving the Morphological and Optical Properties of Sputtered Indium Tin Oxide Thin Films by Adopting Ultralow-Pressure Sputtering

Improving the Morphological and Optical Properties of Sputtered Indium Tin Oxide Thin Films by Adopting Ultralow-Pressure Sputtering

Ultraviolet-induced erasable photochromism in bilayer metal oxide films

Characteristics of IZSO films deposited by a co-sputtering system

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