• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 추계학술대회
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• pp.390-392
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• 2013

본 논문에서는 투명디스플레이를 구현하기 위해 가장 주목받는 ZnO 계열의 산화물반도체의 특성에 대하여 관찰하였다. 알에프 마그네트론 스퍼터링에 의해 증착된 산화물 반도체의 광학적 특성으로부터 전기적인 신호 동작특성의 상호관계를 알아보았다. 박막내의 결합 혹은 불순물이 증가할수록 PL 특성은 장파장 특성이 우세하게 나타났다. SiOC 박막위에서는 에너지 밴드갭이 증가하면서 단파장 특성이 우세하게 나타났다. 트랜지스터의 특성은 기판의 의존도가 높게 나타났다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.252-253
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• 2011

ZnO-based thin film transistors (TFTs) are of great interest for application in next generation flat panel displays. Most research has been based on amorphous indium-gallium-zinc-oxide (IGZO) TFTs, rather than single binary oxides, such as ZnO, due to the reproducibility, uniformity, and surface smoothness of the IGZO active channel layer. However, recently, intrinsic ZnO-TFTs have been investigated, and TFT- arrayss have been demonstrated as prototypes of flat-panel displays and electronic circuits. However, ZnO thin films have some significant problems for application as an active channel layer of TFTs; it was easy to change the electrical properties of the i-ZnO thin films under external conditions. The variable electrical properties lead to unstable TFTs device characteristics under bias stress and/or temperature. In order to obtain higher performance and more stable ZnO-based TFTs, HZO thin film was used as an active channel layer. It was expected that HZO-TFTs would have more stable electrical characteristics under gate bias stress conditions because the binding energy of Hf-O is greater than that of Zn-O. For deposition of HZO thin films, Hf would be substituted with Zn, and then Hf could be suppressed to generate oxygen vacancies. In this study, the fabrication of the oxide-based TFTs with HZO active channel layer was reported with excellent stability. Application of HZO thin films as an active channel layer improved the TFT device performance and bias stability, as compared to i-ZnO TFTs. The excellent negative bias temperature stress (NBTS) stability of the device was analyzed using the HZO and i-ZnO TFTs transfer curves acquired at a high temperature (473 K).

• 한국전기전자재료학회논문지
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• 제31권7호
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• pp.481-485
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• 2018

In this study, oxide/metal/oxide-type transparent electrodes based on Al and ZnO were investigated. Thin films of these materials were sputter-deposited at room temperature. To evaluate the thickness dependence of the oxide layers, the top and bottom ZnO layers were varied in the range of 5~80 nm and 2.5~20 nm, respectively. When the thicknesses of the top and bottom ZnO layers were fixed at 30 nm and 2.5 nm, a maximum transmitance of 66% and sheet resistance of $16.5{\Omega}/{\square}$ were achieved, which is significantly improved compared with the Al layer without top and bottom ZnO layers showing a maximum transmitance of 44.3% and sheet resistance of $44{\Omega}/{\square}$.

• Advances in nano research
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• 제1권1호
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• pp.43-58
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• 2013

Zinc oxide (ZnO) is a unique semiconductor material that exhibits numerous useful properties for dye-sensitized solar cells (DSSCs) and other applications. Various thin-film growth techniques have been used to produce nanowires, nanorods, nanotubes, nanotips, nanosheets, nanobelts and terapods of ZnO. These unique nanostructures unambiguously demonstrate that ZnO probably has the richest family of nanostructures among all materials, both in structures and in properties. The nanostructures could have novel applications in solar cells, optoelectronics, sensors, transducers and biomedical sciences. This article reviews the various nanostructures of ZnO grown by various techniques and their application in DSSCs. The application of ZnO nanowires, nanorods in DSSCs became outstanding, providing a direct pathway to the anode for photo-generated electrons thereby suppressing carrier recombination. This is a novel characteristic which increases the efficiency of ZnO based dye-sensitized solar cells.

• 반도체디스플레이기술학회지
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• 제22권1호
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• pp.78-82
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• 2023

Metal oxide semiconductor (MOS) adapting spray-pyrolysis deposition technique has drawn large attention based on their high quality of intrinsic and electrical properties in addition to simple and low-cost processibility. To fully utilize the merits of MOS field-effect transistors (FETs) , transparency, it is important to understand the instability behaviors of FETs under illumination. Here, we studied the photo-induced properties of nc-ZnO/ZnO field-effect transistors (FETs) based on spray-pyrolysis under illumination which incorporating ZnO nanocrystalline nanoparticles into typical ZnO precursor. Our experiments reveal that nc-ZnO in active layer suppressed the light instabilities of FETs.

• Journal of Microbiology and Biotechnology
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• 제34권6호
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• pp.1229-1238
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• 2024

This study aimed to develop and assess a chitosan biomedical antibacterial gel ZincOxide-GrapheneOxide/Chitosan/β-Glycerophosphate (ZnO-GO/CS/β-GP) loaded with nano-zinc oxide (ZnO) and graphene oxide (GO), known for its potent antibacterial properties, biocompatibility, and sustained drug release. ZnO nanoparticles (ZnO-NPs) were modified and integrated with GO sheets to create 1% and 3% ZnO-GO/CS/β-GP thermo-sensitive hydrogels based on ZnO-GO to Chitosan (CS) mass ratio. Gelation time, pH, structural changes, and microscopic morphology were evaluated. The hydrogel's antibacterial efficacy against Porphyromonas gingivalis, biofilm biomass, and metabolic activity was examined alongside its impact (MC3T3-e1). The findings of this study revealed that both hydrogel formulations exhibited temperature sensitivity, maintaining a neutral pH. The ZnO-GO/CS/β-GP formulation effectively inhibited P. gingivalis bacterial activity and biofilm formation, with a 3% ZnO-GO/CS/β-GP antibacterial rate approaching 100%. MC3T3-e1 cells displayed good biocompatibility when cultured in the hydrogel extract.The ZnO-GO/CS/β-GP thermo-sensitive hydrogel demonstrates favorable physical and chemical properties, effectively preventing P. gingivalis biofilm formation. It exhibits promising biocompatibility, suggesting its potential as an adjuvant therapy for managing and preventing peri-implantitis, subject to further clinical investigations.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.450-450
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• 2012

In recent days, advances in ZnO-based oxide semiconductor materials have accelerated the development of thin-film transistors (TFTs), which are the building blocks for active matrix flat-panel displays including liquid crystal displays (LCD) and organic light-emitting diodes (OLED). In particular, the development of high-mobility ZnO-based channel materials has been proven invaluable; thus, there have been many reports of high-performance TFTs with oxide semiconductor channels such as ZnO, InZnO (IZO), ZnSnO (ZTO), and InGaZnO (IGZO). The reliability of oxide TFTs can be improved by examining more stable oxide channel materials. In the present study, we investigated the effects of an ALD-deposited water vapor permeation barrier on the stability of ZnO and HfZnO (HZO) thin film transistors. The device without the water vapor barrier films showed a large turn-on voltage shift under negative bias temperature stress. On the other hand, the suitably protected device with the lowest water vapor transmission rate showed a dramatically improved device performance. As the value of the water vapor transmission rate of the barrier films was decreased, the turn-on voltage instability reduced. The results suggest that water vapor related traps are strongly related to the instability of ZnO and HfZnO TFTs and that a proper combination of water vapor permeation barriers plays an important role in suppressing the device instability.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.242-242
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• 2012

Transparent oxide semiconductors are increasingly becoming one of good candidates for high efficient channel materials of thin film transistors (TFTs) in large-area display industries. Compare to the conventional hydrogenated amorphous silicon channel layers, solution processed ZnO-TFTs can be simply fabricated at low temperature by just using a spin coating method without vacuum deposition, thus providing low manufacturing cost. Furthermore, solution based oxide TFT exhibits excellent transparency and enables to apply flexible devices. For this reason, this process has been attracting much attention as one fabrication method for oxide channel layer in thin-film transistors (TFTs). But, poor electrical characteristic of these solution based oxide materials still remains one of issuable problems due to oxygen vacancy formed by breaking weak chemical bonds during fabrication. These electrical properties are expected due to the generation of a large number of conducting carriers, resulting in huge electron scattering effect. Therefore, we study a novel technique to effectively improve the electron mobility by applying environmental annealing treatments with various gases to the solution based Li-doped ZnO TFTs. This technique was systematically designed to vary a different lithium ratio in order to confirm the electrical tendency of Li-doped ZnO TFTs. The observations of Scanning Electron Microscopy, Atomic Force Microscopy, and X-ray Photoelectron Spectroscopy were performed to investigate structural properties and elemental composition of our samples. In addition, I-V characteristics were carried out by using Keithley 4,200-Semiconductor Characterization System (4,200-SCS) with 4-probe system.

• 반도체디스플레이기술학회지
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• 제21권3호
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• pp.22-25
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• 2022

Metal oxide semiconductor (MOS) based on spray-pyrolysis deposition technique has attracted large attention due to simple and low-cost processibility while preserving their intrinsic optical and electrical characteristics. However, their high process temperature limits practical applications. Here, we demonstrated the nc-ZnO/ZnO field-effect transistors (FETs) via spray-pyrolysis as incorporating ZnO nanocrystalline nanoparticles into typical ZnO precursor. The nc-ZnO/ZnO FETs exhibit good quality of electrical properties. Our experiments reveal that nc-ZnO in active layer enhance electrical characteristics.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
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• pp.1273-1276
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• 2007

We provide a newly developed dry etching process for the fabrication of ZnO-based oxide TFTs. The etching characteristics of ZnO (active layer) and $Al_2O_3$ (gate insulator) thin films were systematically investigated when the etching gas mixtures and their mixing ratios were varied in the heliconplasma etching system.