• Journal of the Korean Crystal Growth and Crystal Technology
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• v.14 no.6
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• pp.277-280
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• 2004

p-ZnO films have been grown on (0001) sapphire substrates by RF-DC magnetron co-sputtering. The p-ZnO single crystalline thin films of the thickness about 120 nm were grown successfully. The dopant (Aluminum) was sputtered simultaneously from Al metal target by DC sputtering during rf-magnetron sputtering of ZnO at the substrate temperatures of $400^{\circ}C$ and $600^{\circ}C$ respectively. The crystallinity and optical properties of as-grown P-ZnO films have been characterized.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.87-87
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• 2011

Oxide semiconductors are attractive materials for thin-film electronics and optoelectronics due to compatibility with synthesis on large-area, glass and flexible substrate. However, development of thin-film electronics has been hampered by the limited number of semiconducting oxides that are p-type. We report on the effect of the oxygen partial pressure ratio in the gas mixture on the electrical and optical properties of spinel Mg:$ZnCo_2O_4$ thin films deposited at room temperature using RF sputtering, that exhibit p-type conduction. The thin-films are deposited at room temperature in a background of oxygen using a polycrystalline Mg:$ZnCo_2O_4$ ablation target. The p-type conduction is confirmed by positive Seebeck coefficient and positive Hall coefficient. The electrical resistivity and carrier concentration in on dependent Mg:$ZnCo_2O_4$ thin films were found to be dependent on the oxygen partial pressure ratio. As a result, it is revealed that the Mg:$ZnCo_2O_4$ thin-films were greatly influenced on the electrical and optical properties by the oxygen partial pressure condition. The visible region of the spectrum of 36~85%, and hole mobility of 1.1~3.7 $cm^2$/Vs, were obtained.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.106-106
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• 2009

Al-doped ZnO (AZO) thin films were grown on glass substrates by co-sputtering at room temperature. We made ZnO and Al target and ZnO:Al film is deposited with sputter which has two RF gun source. The Al content was controlled by varying Al RF power and effect of Al contents on the properties of ZnO:Al film was investigated. Crystallinity and orientation of the ZnO:Al films were investigated by X-ray diffraction (XRD), surface morphology of the ZnO:Al films was observed by atomic force microscope. Electrical properties of the ZnO:Al films were measured at room temperature by van der Pauw method and hall measurement. Optrical properties of ZnO:Al films were measured by UV-vis-NIR spectrometer.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.1
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• pp.27-30
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• 2002

ZnO co-doped Er:$LiNbO_3$ single crystal thin films have been grown on $LiNbO_3$ (001) substrate by liquid phase epitaxy (LPE) method. The melts of ZnO co-doped Er:$LiNbO_3$ was fixed $Er_2O_3$, concentration (1 mol%) and different ZnO concentrations 3 and 5 mol%. The crystallinity of ZnO co-doped Er :$LiNbO_3$ films became better than the $LiNbO_3$ substrate. At ZnO 5 mol% concentration, the surface of ZnO co-doped Er:$LiNbO_3$ film is affected by compressive stress along both the perpendicular and the parallel direction. Also the surface of ZnO 3 mol% co-doped Er:$LiNbO_3$film is smoother than the original $LiNbO_3$ substrate surface.

• Journal of the Korean institute of surface engineering
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• v.56 no.6
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• pp.451-456
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• 2023

Transparent conducting films having a three layered structure of ZnO/Cu/ZnO (ZCZ) were deposited onto the glass substrates by using RF and DC magnetron sputtering at room temperature. The emissivity and opto-electrical properties of the films were investigated with a varying thickness(5, 10, 15 nm) of the Cu interlayer. With increasing the Cu thickness to 15 nm, the films showed a enhanced electrical properties. Although ZnO 30/Cu 15/ZnO 30 nm film shows a lower resistivity of 5.2×10^-5 Ωcm, it's visible transmittance is deteriorated by increased optical absorbtion of the films. In addition, X-ray diffraction patterns indicated that the insertion of Cu interlayer improve the grain size of ZnO films, which is favor for the electrical and optical properties of transparent conducting films. From the observed low emissivity of the films, it is concluded that the ZCZ thin films with optimal thickness of Cu interlayer can be applied effectively for the car's window coating materials.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.91-91
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• 2012

We aim in synthesizing various functional thin films thinner than ~ 10 nm for environmental applications and photovoltaic devices. Atomic layer deposition is used for synthesizing inorganic thin films with a precise control of the film thickness. Several examples about application of our thin films for removing volatile organic compounds (VOC) will be highlighted, which are summarized in the below. 1) $TiO_2$ thin films prepared by ALD at low temperature ($<100^{\circ}C$) show high adsorption capacity for toluene. In combination with nanostructured templates, $TiO_2$ thin films can be used as building-block of high-performing VOC filter. 2) $TiO_2$ thin films on carbon fibers and nanodiamonds annealed at high temperatures are active for photocatalytic oxidation of VOCs, i.e. photocatalytic filter can be created by atomic layer deposition. 3) NiO can catalyze oxidation of toluene to $CO_2$ and $H_2O$ at $<300^{\circ}C$. $TiO_2$ thin films on NiO can reduce poisoning of NiO surfaces by reaction intermediates below $200^{\circ}C$. We also fabricated inverted organic solar cell based on ZnO electron collecting layers on ITO. $TiO_2$ thin films with a mean diameter less than 3 nm on ZnO can enhance photovoltaic performance by reducing electron-hole recombination on ZnO surfaces.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.2
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• pp.91-95
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• 2012

ZnO thin films were deposited on p-type 4H-SiC substrate by pulsed laser deposition. ZnO nanowires were formed on p-type 4H-SiC substrate by furnace. Ti/Au electrodes were deposited on ZnO thin film/SiC and ZnO nanowire/SiC structures, respectively. Structural and crystallographical properties of the fabricated ZnO thin film/SiC and ZnO nanowire/SiC structures were investigated by field emission scanning electron microscope and X-ray diffraction. In this work, resistance and sensitivity of ZnO thin film/SiC gas sensor and ZnO nanowire/SiC gas sensor were measured at $300^{\circ}C$ with various CO gas concentrations (0%, 90%, 70%, and 50%). Resistance of gas sensor decreases at CO gas atmosphere. Sensitivity of ZnO nanowire/SiC gas sensor is twice as big as sensitivity of ZnO thin film/SiC gas sensor.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.309-309
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• 2010

We have investigated the effect of $H_2$ plasma treatment on the BZO (ZnO:B, Boron doped ZnO) thin films. The BZO thin films are prepared by LP-MOCVD (Low Pressure Metal Organic Chemical Vapor Deposition) technique and the samples of BZO thin film are performed with $H_2$ plasma treatment by plasma treatment system with 13.56 MHz as RIE (Reactive Ion Etching) type. After exposing $H_2$ plasma treatment, measurement of transmittance, reflectance and haze spectra in 300~1100 nm, electrical properties as resistivity, mobility and carrier concentration and work function was analysed. Regarding the results of the $H_2$ plasma treatment on the BZO thin films are application to the TCO for solar cells, such as the a-Si thin films solar cell.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.302.1-302.1
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• 2014

We report the growth of high quality zinc oxide (ZnO) thin films on amorphous glass substrates and their structural and optical characteristics. For the growth of ZnO films, mechanically exfoliated ultrathin graphite or graphene layers were used as an intermediate layer because ZnO does not have any heteroepitaxial relationship with the amorphous substrates, which significantly improved the crystallinity of the ZnO films. Structural and optical characteristics of the films were investigated using scanning and transmission electron microscopy, x-ray diffraction, and variable temperature photoluminescence spectroscopy. High crystallinity and excellent optical characteristics such as stimulated emission were exhibited from the high quality ZnO films grown on glass substrates.

• Journal of the Korean Ceramic Society
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• v.43 no.11 s.294
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• pp.738-742
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• 2006

We report on the effects of co-doping with fluorine on properties of ZnO thin films grown by pulsed-laser deposition. The transport characteristics of Ag-F and Li-F codoped ZnO films were determined by Hall-effect measurements at room temperature. Ag-F codoped ZnO films showed n-type semiconducting behaviors. An ambiguous carrier type was observed in Li-F codoped ZnO films grown at a temperature of 500$^{\circ}C$ with the oxygen pressures of 20 and 200 mTorr. The qualities of the codoped ZnO films were studied by X-ray diffraction, atomic force microscopy, X-ray photoemission spectroscopy, and photoluminescence.