• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.3
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• pp.214-218
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• 2020

In this study, Mg_xZn_1-xO thin films, which can be applied not only to active layers of light-emitting devices (LEDs), such as UV-LEDs, but also to solar cells, high mobility field-effect transistors, and power semiconductor devices, are fabricated using the sol-gel method. ZnO and Mg_0.3Zn_0.7O solution synthesized by the sol-gel method and the thin film were grown by spin coating on a Si (100) substrate and sapphire substrate. The solutions are synthesized by dissolving precursor materials in 2-methoxyethanol (2-ME) solvent, and then monoethanolamine (MEA) was added to the mixed solution as a sol stabilizer. Zinc acetate dihydrate is used as a ZnO precursor, while Mg nitrate hexahydrate and Mg acetate tetrahydrate are used as an MgO precursor. Then, the optical and structural characteristics of the fabricated thin films are compared. The molar concentration of the Zn precursor in the solvent is fixed at 0.3 M, and the amount of the Mg precursor is 30% of Mg²⁺/Zn²⁺. The optical characteristics are measured using an UV-vis spectrophotometer, and the transmittance of each wavelength is measured. Structural characteristics are measured using X-ray diffraction (XRD) and transmission electron microscopy (TEM). Composition analyses are performed using energy dispersive X-ray spectroscopy (EDS). The Mg_0.3Zn_0.7O thin film was well formed at the ratio of the Mg precursor added regardless of the type of Mg precursor, and the c-axis of the thin film was decreased, while the band gap was increased to 3.56 eV.

• Journal of the Semiconductor & Display Technology
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• v.20 no.3
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• pp.22-26
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• 2021

Thin-film encapsulation (TFE) technology is most effective in preventing water vapor and oxygen permeation in the organic light emitting diodes (OLED). Of those, a laminated structure of Al₂O₃ and MgO were applied to provide efficient barrier performance for increasing the stability of devices in air. Atomic layer deposition (ALD) method is known as the most promising technology for making the laminated Al₂O₃/MgO and is used to realize a thin film encapsulation technology in organic light-emitting diodes. Atomic layer deposited inorganic films have superior barrier performance and have advantages of excellent uniformity over large scales at relatively low deposition temperatures. In this study, the control system of the MgCP₂ precursor for the atomic layer deposition of MgO was established in order to deposit the MgO layer stably by the injection time of second level and the stable heating temperature. The deposition rate was obtained stably to be from 4 to 10 Å/cycle using the injection pulse times ranging from 3 to 12 sec and a substrate temperature ranging from 80 to 150 ℃.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.579-582
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• 2004

[ $Mg_xZn_{1-x}O$ ] thin films on (001) sapphire substrates have been deposited by pulsed laser deposition (PLD). The substrate temperature has been varied from $200^{\circ}C$ to $600^{\circ}C$ in order to control Mg content in $Mg_xZn_{1-x}O$ thin film. $Mg_xZn_{1-x}O$ thin films deposited at 200, 400 and $600^{\circ}C$ were annealed at temperatures of $800^{\circ}C$. The ratio of Mg was mesured by Rutherford backscattering spectrometry. The optical properties of $Mg_xZn_{1-x}O$ thin films were characterized by photomulinesence. The ratio of Mg was varied depending on the deposition temperatures which resulted in the change of energy bandgap.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.278-279
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• 2005

The crystallization of FePt/MgO(100) magnetic thin films of various thicknesses has been studied using synchrotron x-ray scattering, atomic force microscope, and vibrating sample magnetometer. In film with a 500-${\AA}$-thick, ordered (fct) FePt phase was dominantly crystallized into perpendicular (001) grains keeping the magnetically easy c-axis normal to the film plane during annealing. In film with a 812-${\AA}$-thick, however, longitudinal (110) grains keeping the c-axis parallel to the film plane were grown on top of the perpendicular (001) grains. The behavior of the magnetic properties was consistent with the thickness dependence of the crystallization. We attribute the thickness dependence of the crystallization to the substrate effect, which prefers the growth of the c-axis oriented perpendicular grains near the film/substrate interfacial area.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1279_1280
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• 2009

Vanadium dioxide(VO2) has been reported to be the most attractive material for thermochromic windows due to its semiconductor-metal phase transition at around $68^{\circ}C$. However, our previous experiment showed it is difficult to grow VO2 thin films directly on glass substrate, whereas thermochromic VO2 thin films were successfully grown on R-cut sapphire substrate. Properties of VO2 thin films on different orientations of sapphire substrates were already reported. Furthermore, VO2 thin films were successfully grown heteroepitaxially on (001) preferred oriented ZnO coated glass. We deposited VO2 thin films using V2O5 targets on substrates with various lattice parameters with same orientation(SrTiO3, MgO, and Sapphire substrate of (001) orientation) by pulsed laser deposition. In this work, we will discuss the effects of lattice misfit, substrate-induced stress and grain size on the properties of VO2 thin films deposited on various substrate materials.

• Journal of the Korean Ceramic Society
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• v.33 no.3
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• pp.299-306
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• 1996

We invesgated the fesibility of thin films deposition by pyrolysis of metalorganic precursors using chemical beam deposition (CBD) process. We attempted to understand the effects of deposition variables such as substrate temperature operating pressure effusion cell temperature and H2 partial pressure on the properties of MgF2 grown by CBD. Mg(tfac)2 was used as a precursor. MgF2 thin films were always grown in an amorphous state and crystallized bypost-annealing. he higher the substrate temperature and the lower the operating pressure the less the impurities I the deposited MgF2 thin films. H2 gas has to be supplied for the pyrolitic reaction of Mg(tfac)2 decomposition. MgF2 films annealed in H2 have lower C impurity than those annealed in O2. But their crysatllinity was independent of annealing atmosphere. The optimum conditions for the prepara-tion of MgF2 films by CBD process were as following : The substrate temperature 55$0^{\circ}C$ the operating pressure 10-4 torr; effusion cell temperature 21$0^{\circ}C$ the percentage of H2 100% Post-annealing in H2 gas was required to remove residual carbon and to form MgF2 crystalline phase.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04a
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• pp.133-138
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• 2000

MgO thin films were deposited using $Mg(tmhd)_2$ as a precursor dissolved in a solvent by electrostatic spray pyrolysis. When a pure tetra hydro furan was used as a solvent, a large number of particles appeared on the MgO thin film surface due to homogeneous nucleation. However, by adding 1-butyl alcohol or 1-octyl alcohol to THF, homogeneous nucleation was restricted and the number density of the large particles was also drastically reduced. X-ray diffraction analysis showed that the MgO films had a (100) preferred orientation regardless of the type of solvents used. Characterization using Fourier Transformed-Infrared and spectroscopic photometer revealed that the crystallized MgO thin films on the glass substrate had a high optical transmittance (> 85 %) in the visible range. Discharge characteristics of MgO thin films deposited by ESP method on an alternating-current plasma display panel were compared with a MgO thin film prepared by reactive radio-frequency planar magnetron sputtering.

• Journal of the Korean Vacuum Society
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• v.10 no.4
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• pp.396-402
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• 2001

MgO thin films with 1000 $\AA$ thickness were deposited on Cu substrates by using an electron gun evaporator at room temperature. A 1000 $\AA$ thick Al layer was deposited on the MgO for removing the charging effect of the MgO thin film during the measurements of the sputtering yields. A Ga ion liquid metal was used as the focused ion beam(FIB) source. The ion beam was focused by using double einzel lenses, and a deflector was employed to scan the ion beams into the MgO layer. Both currents of the secondary particle and the probe ion beam were measured, and they dramatically changed with varying the applied acceleration voltage of the source. The sputtering yield of the MgO layer was determined using the values of the analyzed probe current, the secondary particle current, and the net current. When the acceleration voltage of the FIB system was 15 kV, the sputtering yield of the MgO thin film was 0.30. The sputtering yield of the MgO thin film linearly increases with the acceleration voltage. These results indicate that the FIB system is promising for the measurements of the sputtering yield of the MgO thin film.

• Journal of the Korean Ceramic Society
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• v.41 no.12 s.271
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• pp.880-883
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• 2004

Carbon nanofibers could be selectively formed at the groove area of the MgO substrate using microwave plasma-enhanced chemical vapor deposition system. Iridium metal was used as a catalyst layer for the formation of the carbon nanofibers. The growth direction of the carbon nanofibers was vertical to the substrate surface. The selectively grown iridium-catalyzed carbon nanofibers show around $1.8V/{\mu}m$ turn-on voltage and $1.0\;mA/cm^2$ field emission current density at $2.65\;V/{\mu}m$ in the field emission measurement.

• Current Photovoltaic Research
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• v.4 no.4
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• pp.150-154
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• 2016

Mg and In co-doped ZnO (MIZO) thin films with transparent conducting characteristics were successfully prepared on glass substrates by RF magnetron sputtering technique. The Influence of different substrate temperature (from RT to $400^{\circ}C$) on the structural, morphological, electrical, and optical properties of MIZO thin films were investigated. The MIZO thin film prepared at the substrate temperature of $350^{\circ}C$ showed the best electrical characteristics in terms of the carrier concentration ($4.24{\times}10^{20}cm^{-3}$), charge carrier mobility ($5.01cm^2V^{-1}S^{-1}$), and a minimum resistivity ($1.24{\times}10^{-4}{\Omega}{\cdot}cm$). The average transmission of MIZO thin films in the visible range was over 80% and the absorption edges of MIZO thin films were very sharp. The bandgap energy of MIZO thin films becomes wider from 3.44 eV to 3.6 eV as the substrate temperature increased from RT to $350^{\circ}C$. However, Band gap energy of MIZO thin film was narrow at substrate temperature of $400^{\circ}C$.