• Journal of the Semiconductor & Display Technology
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• v.12 no.2
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• pp.33-37
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• 2013

In this study, we have investigated the effect of the substrate temperature and hydrogen flow rate on the characteristics of IZO thin films for the organic light emitting diodes (OLED) devices. For this purpose, IZO thin films were deposited by RF magnetron sputtering at room temperature and $300^{\circ}C$ with various $H_2$ flow rate. In order to investigate the influences of the oxygen, the flow rate of hydrogen in argon mixing gas has been changed from 0.1sccm to 0.9sccm. IZO thin films deposited at room temperature show amorphous structure, whereas IZO thin films deposited at $300^{\circ}C$ show crystalline structure having an (222) preferential orientation regardless of $H_2$ flow rate. The electrical resistivity of IZO film decreased with increasing flow rate of $H_2$ under Ar+$H_2$. The change of electrical resistivity with increasing flow rate of $H_2$ was mainly interpreted in terms of the charge carrier concentration rather than the charge carrier mobility. The electrical resistivity of the amorphous-IZO films deposited at R.T. was lower than that of the crystalline-IZO thin films deposited at $300^{\circ}C$. The increase of electrical resistivity with increasing substrate temperature was interpreted in terms of the decrease of the charge carrier mobility and the charge carrier concentration. All the films showed the average transmittance over 83% in the visible range.

• Journal of the Korean Ceramic Society
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• v.47 no.4
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• pp.329-332
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• 2010

In order to investigate the effect of tail state on the electrical and the optical properties in amorphous IGZO(a-IGZO), a-IGZO films were deposited at room temperature on fused silica substrats using pulsed laser deposition method. The laser pulse energy was used as the processing parameter. In-situ post annealing was carried out at $150^{\circ}C$ right after the film deposition. The $O_2$ partial pressure during the deposition and the post annealing was fixed to 10mTorr. The carrier mobility of the a-IGZO films had a range from 2 to $18\;cm^2/Vs$ at carrier concentrations greater than $10^{18}\;cm^{-3}$. As the laser energy density increased, the Hall mobility increased. And post annealing improved the Hall mobility, as well. The optical property was examined using the ultraviolet-visible spectroscopy. The a-IGZO films that have low Hall mobility exhibited stronger and broader absorption tails in >3.0 eV region. Post annealing reduced the intensity of the tail-like absorption. The absorption tail in a-IGZO films is an important factor which affects the electrical and the optical properties.

• Polymer(Korea)
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• v.25 no.5
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• pp.719-727
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• 2001

Recently it was found that the charge carrier transport properties are significantly enhanced due to effective intermolecular $\pi$-orbital overlapping and low disorder of hopping sites caused by self-organization of liquid crystal molecules. In this study, the xerographic properties of a double-layer photoconductor doped with nematic liquid crystal, 4-pentyl-4'-cyanoterphenyl (5CT), as a charge-carrier transport material to enhance the charge-tarrier mobility were investigated. From the results of measured surface voltage properties for the photoconductor doped with various concentrations of liquid crystal, 5CT, the initial voltage was found to increase with the concentration of 5CT and the dark decay decreased with the concentration of 5CT. The highest sensitivity was obtained at a specific concentration, 40wt% 5CT. The fluorescence behavior of the carrier transport layer (CTL) was also investigated. It was found that the charge-carrier transport properties of the organic photoconductor depend on the charge-carrier transport properties of the complex. The TNF : 5CT (40 wt%) and OXD : 5CT (40 wt%)samples showed the highest sensitivity because the greatest charge transport complex was termed between the charge-carrier transport materials in these samples.

• Membrane Journal
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• v.27 no.3
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• pp.205-215
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• 2017

Polymer membranes are cheap and easy in fabrication, and show a high permeability and selectivity, thus play pivotal roles in gas separation as well as water purification. However, polymer membranes typically exhibit the trade-off relation between permeability and selectivity; i.e. when the permeability is high, the selectivity is low and vice versa. Facilitated transport has been considered one of the solutions to address this issue. Over the last decades, facilitated transport concept had played an important role in preparing the membranes and providing ideal and various models for the transport. Understanding the nature of carrier, the mobility of matrix and the physico-chemical properties of polymer composites are crucial for facilitated transport. Depending on the mobility of carrier, facilitated transport membrane is classified into three; mobile carrier membrane, semi-mobile carrier membrane, fixed-site carrier membrane. Also, there are four types of reversible reaction between the carrier and the specific target; proton transfer reaction, nucleophilic addition reaction, p-complexation reaction and electrochemical reaction. The facilitated transport membranes have been applied in the separation of CO2, O2 and olefin (propylene or ethylene). In this review, major challenges surrounding facilitated transport membranes and the strategies to tackle these challenges are given in detail.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.782-784
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• 2002

Many compound semiconductors which have high carrier mobility and small band gap have attentive in application of various practical a field. Especially, InSb served for Hall device and magnetic resistor such as magnetic sensor because InSb thin film has high mobility. Many studies on InSb thin film deposition because In and Sb has been very different feature of vapor pressure($10^4$ times) When In and Sb deposited. In this paper studied it In and Sb deposited simultaneously using by method of co-sputtering deposotion. This process, get to effects of manufacture process simplification. After that this paper observed micro structure and electronic behavior of InSb thin film using by co-sputtering.

• Journal of IKEEE
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• v.22 no.2
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• pp.484-487
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• 2018

5 MeV proton-irradiation with total dose of $10^{15}/cm^2$ was performed on AlGaN/GaN-on-Si high electron mobility transistors (HEMTs) with various gate metals including Ni, TaN, W, and TiN to investigate the degradation characteristics. The positive shift of pinch-off voltage and the reduction of on-current were observed from irradiated HEMTs regardless of a type of gate materials. Hall and transmission line measurements revealed the reduction of carrier mobility and sheet charge concentration due to displacement damage by proton irradiation. The shift of pinch-off voltage was dependent on Schottky barrier heights of gate metals. Gate leakage and capacitance-voltage characteristics did not show any significant degradation demonstrating the superior radiation hardness of Schottky gate contacts on GaN.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.305-306
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• 2005

The effects of As addition In amorphous selenium (a-Se) films for digital X-ray conversion material have been studied using the moving photocarrier grating (MPG) technique We have found an increase in hole drift mobility and recombination lifetime, especially when 0.3% As is added into a-Se film, whereas electron mobility decreases with As addition due to the defect density. The transport properties for As doped a-Se films obtained by using MPG technique have been compared with X-ray sensitivity for a-Se:As X-ray device. The fabricated a-Se (0.3%As) based X-ray detector exhibited the highest X-ray sensitivity of 5 samples.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.8 no.2
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• pp.54-62
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• 1983

The electric characteristics of semiconductor materials can be found by way of various methods, of which the measurement of the carrier mobility is thought to be of great importance. There exist some mobilty measurements, but the measurement based on Hall effect is the most widely uesd. In this paper is adopted the mobility measurement of semiconductor by the use of cylindrical eavity operated in the same shape as TE modes. It is hoped that the resultant values of measurement, the structure of measurement circut, cavity design and the raising of relevant problems may give much help to those who may interested in this field.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.370-374
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• 2002

Many compound semiconductors which have high carrier mobility and small band gap have attentive in application of various practical a field. Especially, InSb served for Hall device and magnetic resistor such as magnetic sensor because InSb thin film has high mobility. Many studies on InSb thin film deposistion because In and Sb has been very different feature of vapor pressure ($10^{-4}$ times) When In and Sb deposited. In this paper studied it In and Sb deposited simultaneously using by method of co-sputtering deposotion. This process, get to effects of manufacture process simplification. After that this paper observed micro structure and electronic behavior of InSb thin film using by co-sputtering and we study properties of magneto-resistance by annealing.

• Journal of Electrical Engineering and Technology
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• v.9 no.2
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• pp.609-614
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• 2014

We fabricated amorphous zinc tin oxide (ZTO) transparent thin-film transistors (TTFTs). The effects of Al electrode on the mobility and threshold voltage of the ZTO TTFTs were investigated. It was found that the aluminum (Al)-ZTO contact decreased the mobility and increased the threshold voltage. Traps, originating from $AlO_x$, were assumed to be the cause of degradation. An indium tin oxide film was inserted between Al and ZTO as a buffer layer, forming an ohmic contact, which was revealed to improve the performance of ZTO TTFTs.