• Journal of the Korean Ceramic Society
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• v.41 no.1
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• pp.57-61
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• 2004

Zinc Oxide (ZnO) have the crystal structure of wurtzite which is semiconducting oxide with band gap energy of 3.3eV. $In_2O_3$-doped ZnO films were fabricated by electron beam evaporation at $400^{\circ}C$ and their characteristics were investigated. The content of $In_2O_3$ in ZnO films had a marked effect on the electrical properties of the films. As $In_2O_3$ content decreased. $In_2O_3$-doped ZnO films was converted amorphous into crystallized films and showed a better characteristics generally as a transparent conducting oxide. As $In_2O_3$-doped ZnO films were prepared by $In_2O_3$-doped ZnO pellet with 0.2at% of $In_2O_3$ content, the value of resistivity was about $6.0 {\times} 10^{-3} {\Omega}cm$. The transmittance was higher than 85% throughout the visible range.

• Journal of the Korean Ceramic Society
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• v.23 no.1
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• pp.44-50
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• 1986

Si-ZnO n-n heterojunction diodes were prespared by r.f diode sputtering of the sintered ZnO target on n-type Si single crystal wafers and their structures and electrical properties were studied. The films were grown orientedly with the c-axis of crystallites perpendicular to the substrate surface at low r.f. powder and grown to polycrystalline films with random orientation at high r. f. powder. The crystallite size increased with the increasing substrate temperture The oriented texture films only were used to prepare the photovoltaic diodes and these didoes showed the photovoltaic effect veing positive of the ZnO side for the photons in the wavelength range of 380-1450nm. The sign reversal of phootovoltage which is the property os isotype heterojunction was not observed because of the degeneration of the ZnO films. The diode showed the forward rectification when it was biased with the ZnO side positive. The current-voltage characteristics exhibited the thermal-current type relationship J∝exp(qV/nkT) with n=1.23 at the low forward bias voltage and the tunnelling-current type relationship J∝exp($\alpha$V) where $\alpha$ was constant independent of temperature at the high forward bias voltage. The crystallite size of ZnO films were influenced largely on the photovoltaic properties of diodes ; The diodes with the films of the larger crystallites showed the poor photovoltaic properties. This reason may be cosidered that the ZnO films with the large crystallites could not grow to the electrically continuous films because the thickness of films was so thin in this experiment.

• Transactions on Electrical and Electronic Materials
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• v.9 no.1
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• pp.24-27
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• 2008

ZnO has intensively attracted interest for the next generation of short wavelength LEDs and semiconductor lasers. However, for the development and application of the devices based on this material, the fabrication of p-type ZnO thin films is pivotal. Generally, the process of preparation of ZnO is unavoidably accompanied by the natural donor ions such as interstitial Zn ions and oxygen vacancy ions that show n-type electrical property and make fabrication of p-type ZnO to be a hard problem. On this study, to realize stable high-quality p-type ZnO thin films, the undoped ZnO thin films were diffused with P in vapor state. The ZnO:P thin films showed high-quality p-type properties electrically and optically.

• Transactions on Electrical and Electronic Materials
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• v.10 no.1
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• pp.24-27
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• 2009

N-doped ZnO thin films were deposited on n-type Si(100) and homo-buffer layer, and undoped ZnO thin film was also deposited on homo-buffer layer by RF magnetron sputtering method. After deposition, all films were in-situ annealed at $800^{\circ}C$ for 5 minutes in ambient of $O_2$ with pressure of 10Torr. X -ray diffraction shows that the homo-buffer layer is beneficial to the crystalline of N-doped ZnO thin films and all films have preferable c-axis orientation. Atomic force microscopy shows that undoped ZnO thin film grown on homo-buffer layer has an evident improvement of smoothness compared with N-dope ZnO thin films. Hall-effect measurements show that all ZnO films annealed at $800^{\circ}C$ possess p-type conductivities. The undoped ZnO film has the highest carrier concentration of $1.145{\times}10^{17}cm{-3}$. The photoluminescence spectra show the emissions related to FE, DAP and many defects such as $V_{Zn}$, $Zn_O$, $O_i$ and $O_{Zn}$. The p-type defects ($O_i$, $V_{Zn}$, and $O_{Zn}$) are dominant. The undoped ZnO thin film has a better p-type conductivity compared with N-doped ZnO thin film.

• Electrical & Electronic Materials
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• v.9 no.9
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• pp.925-932
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• 1996

Using the d.c. 2-probe method, we have examined the temperature dependence of CO gas sensitivity of pure ZnO and ZnO CuO thick films prepared by the acqueous precipitation. At 200ppm CO gas, pure ZnO thick film shows the maximum sensitivity of -6.5 at 300.deg. C. On the other hand, the maximum sensitivity of 1-5 mol% and 10-15 mol% CuO added ZnO thick films are 2.8-2.5 and 1.6, respectively. Therefore, the sensitivity of pure ZnO thick film is about three times larger than those of ZnO-CuO thick films. We suggest that the promotion of maximum sensitivity is caused by low packing and the increase of chemical adsorptions for $O_{2}$ gas.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.235-236
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• 2008

Wet etched ZnO:Al films for thin film solar cells were prepared by Facing Target sputtering(FTS) method. Wet etching has been used to produce a rough TCO surface that enables light trapping in the absorber. The ZnO:Al films for thin film solar cells were etched by HCl 0.5%. The etching performance of ZnO:Al films can be tuned by changing etching time. The etched ZnO:Al films compared to a smooth ZnO:Al thin film structure. From the results, the lowest resistivity of deposited films was $5.67\times10^{-4}$ [$\Omega$-cm] and the transmittance of all ZnO:Al thin films were over 80% in visible range.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.3
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• pp.103-108
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• 2005

ZnO thin films on (001) sapphire substrates have been deposited by pulsed laser deposition(PLD) technique using an Nd:YAG laser with a wavelength of 266nm. Before post-annealing treatment in the oxygen ambient, the experiment of the deposition of ZnO thin films has been performed for substrate temperatures in the range of $300\~450^{\circ}C$ and oxygen gas flow rate of $100\~700\;sccm$. In order to investigate the effect of post-annealing treatment of ZnO thin films, films have been annealed at various temperatures after deposition. After post-annealing treatment in the oxygen ambient, the structural properties of ZnO thin films were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM) and the optical properties of the ZnO were characterized by photoluminescence(PL).

• Journal of the Semiconductor & Display Technology
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• v.10 no.2
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• pp.83-89
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• 2011

In this study, we investigated the effects of shutter control by Reactive Magnetron Sputtering using Inductively-Coupled Plasma(ICP) for obtaining ZnO thin films with high purity. The surface morphologies and structure of deposited ZnO thin films were characterized using Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and X-ray Diffractometer (XRD). Also, optical and chemical properties of ZnO thin films were analyzed by Spectroscopic Ellipsometer (SE) and X-ray Photoelectron spectroscopy (XPS). As a result, it observed that ZnO thin films grown at reactive sputtering using shutter control and ICP were higher density, lower surface roughness, better crystallinity than other conventional sputtering deposition methods. For obtaining better quality deposition ZnO thin films, we will investigate the effects of substrate temperature and RF power on shutter control by a reactive magnetron sputtering using inductively-coupled plasma.

• Journal of the Korean institute of surface engineering
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• v.55 no.2
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• pp.91-95
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• 2022

ZnO single layer (60 nm thick) and ZnO with Ag interlayer (ZnO/Ag/ZnO; ZAZ) films were deposited on the glass substrates by using radio frequency (RF) and direct current (DC) magnetron sputter to evaluate the effectiveness of Ag interlayer on the optical visible transmittance and the conductivity of the films. In the ZAZ films, the thickness of ZnO layers was kept at 30 nm, while the Ag thickness was varied as 5, 10, 15 and 20 nm. In X-ray diffraction (XRD) analysis, ZnO films show the (002) diffraction peak and ZAZ films also show the weak ZnO (002) peak and Ag (111) diffraction peak. As a thickness of Ag interlayer increased to 20 nm, the grain size of the Ag films enlarged to 11.42 nm and the optical band gap also increased from 4.15 to 4.22 eV with carrier concentration increasing from 4.9 to 10.5×10²¹ cm^-3. In figure of merit measurements, the ZAZ films with a 10 nm thick Ag interlayer showed the higher figure of merit of 4.0×10^-3 Ω^-1 than the ZnO single layer and another ZAZ films. From the experimental result, it is assumed that the Ag interlayer enhanced effectively the opto-electrical performance of the ZAZ films.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.14 no.6
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• pp.253-256
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• 2004

Growth of ZnO epitaxial films have been carried out on (0001) sapphire substrates by RF magnetron sputtering. The single crystalline ZnO films of the thickness about 400-500 mm were grown successfully. At the various substrate temperatures of 200～$600^{\circ}C$, the growth behavior and optical properties of the epitaxial films have been characterized. As-grown ZnO films were annealed at the temperatures of 400, 600 and $800^{\circ}C$ respectively in order to characterize the optical properties. The carrier concentration of ZnO films annealed at the temperature of $600^{\circ}C$ was measured $2.6${\times}$10^{16}\textrm{cm}^{-3}$ by Hall measurements.