• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.7
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• pp.304-307
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• 2005

The $In_2S_3\;and\;In_2S_3:Co^{2+}$ thin films were grown by the spray Pyrolysis method. The thin films crystallized into tetragonal structures. The indirect energy band gap was 2.32ev for $In_2S_3\;and\;1.81eV\;for\;In_2S_3:Co^{2+}$ at 298K. The direct energy band gap was 2.67ev for $In_2S_3:Co^{2+}$ thin films. Impurity optical absorption peaks were observed for the $In_2S_3:Co^{2+}$ thin films. These impurity absorption peaks are assigned, based on the crystal field theory to the electron transitions between the energy levels of the $Co^{2+}$ ion sited in $T_{d}$ symmetry. The electrical conductivity($\sigma$), Hall mobility(${\mu}_H$), and carrier concentration (n) of the $In_2Se_3$ thin film were measured, and their temperature dependence was investigated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.188-193
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• 1997

ZnO thin film had been deposited on the glass 7r sputtering method, and investigated by electrical and structural properties. When the rf power was 188W and sputtering pressure was 1$\times$10$^{-3}$ Torr at room temperature, Al-doped ZnO thin film had the lowest resistivity(1$\times$10$^{-4}$ $\Omega$.cm), and then carrier concentration and Hall mobility were 6.27$\times$10$^{20}$ cm$^{-3}$ and 22.04$\textrm{cm}^2$/V.s, respectively. And undoped ZnO thin film had about 10$^{14}$ $\Omega$.cm resistivity when oxygen content was 10% or more at room temperature. The surface morphology of ZnO thin film observed by SEM was overall uniform when oxygen content was 50% below and sputtering pressure was 1.0$\times$10$^{-1}$ Torr.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.82-83
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• 2008

AI doped ZnO (AZO) films, and intentionally Zn added AZO (ZAZO) films were prepared on Corning glass by rf magnetron sputtering, and the electrical, optical, and structural properties of the as-deposited films together with the air annealed films were investigated. The resistivity of the AZO films increased with increasing substrate temperature and having minimum resistivity at $150^{\circ}C$. At the high temperature, the ZAZO films showed improved electrical properties better than the AZO films due.to increase in both the carrier concentration and.the Hall mobility. Upon air annealing at $500^{\circ}C$, the resistivity of both AZO and ZAZO films increased substantially, but the relative amount of degradation was smaller for films deposited at $450^{\circ}C$ than the films deposited at $150^{\circ}C$.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.3
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• pp.124-133
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• 1995

A theoretical self-consistent thermoelectric model has been developed for optimal thermal design in the self-signal processing infraed detectors. The model is achived by employing the coupled thermoelectric equation which allows which allows the simultaneous investigation of the termal and electrical aspects of device behavior. The thermal limitation of detectivity and responsivity are determined by the enegy gap, carrier concentration, lifetime, and mobility as a function of the temperature. The calculated results indicate that the detectivity is decreased at bias fields above about 50 V/cm, because the performence is limiting by temperature when the bias voltage reached the level associated with Joule heating. It has been also found that the improvement in the mid-band modulation transfer function(MTF) may be restricted by increasing the bias fields. Further, the important paramerers in the thermal optimization of SPIR detector, such as temperature in the device, ambipolar velocity, element thickness and length, are also considered. The analytical study provides a mathematical basis for optimal design of such a photoconductive IR detector and the agreement between the experimental and theoretical results are seen to be good.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.981-982
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• 2006

In this study, the synthesis and semiconducting properties of cation and defect-doped KTaO3 film is reported. KTaO3is an important material for optoelectronic and tunable microwave applications. It is an incipient ferroelectric with a cubic structure that becomes ferroelectric when doped with Nb. the films were grown on (001) MgO single crystal substrates using pulsed-laser deposition. Semiconducting behavior is achieved by inducing oxygen vacancies in the KTaO3 lattice via growth in a hydrogen atmosphere. The resistivity of semiconducting KTaO3:Ca films was as low as 10cm, and n-type semiconducting behavior was indicated. Hall mobility and carrier concentration were 0.27 cm2/Vs and 3.21018cm-3.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.173-176
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• 1997

The III-V nitride semiconductor InN thin films which have the direct bandgap in visible light wavelength region have been deposited on Si(100) substrates and AIN/Si(100) substrates by rf reactive sputtering. InN thin films have been investigated on the structural, and electrical properties according to the sputtering parameters such as total pressure, rf power, and substrate temperature. It is found that optimal conditions required for fabricating InN thin films with high crystal Quality, low carrier concentration, high Hall mobility are total pressure 5mTorr, rf power 60W, substrate temperature 6$0^{\circ}C$ . InN thin films deposited on the AIN(60min.)/Si(100) substrates arid AIN(120min.)/Si(100) substrates showed remarkably high crystal quality and electrical properties. It is known that AIN buffer layer is to decrease free energy at interface between InN film and Si substrate, and then promoting lateral growth of InN films.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.4
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• pp.272-275
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• 2019

We investigated the electrical characteristics of amorphous silicon-zinc-tin-oxide (a-SZTO) thin films deposited by RF-magnetron sputtering at room temperature depending on the deposition time. We fabricated a thin film transistor (TFT) with a bottom gate structure and various channel thicknesses. With increasing channel thickness, the threshold voltage shifted negatively from -0.44 V to -2.18 V, the on current ($I_{on}$) and field effect mobility (${\mu}_{FE}$) increased because of increasing carrier concentration. The a-SZTO film was fabricated and analyzed in terms of the contact resistance and channel resistance. In this study, the transmission line method (TLM) was adopted and investigated. With increasing channel thickness, the contact resistance and sheet resistance both decreased.

• Journal of Magnetics
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• v.11 no.1
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• pp.1-4
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• 2006

We report on the growth, structural and transport properties of zinc-blende CrAs/GaAs/MnAs/GaAs multilayers on GaAs(001) substrates. Structural analyses using in-situ reflection high-energy electron diffraction and exsitu cross-sectional transmission electron microscopy confirmed the realization of a zinc-blende crystal structure. Room temperature Hall measurements reveal that the as-grown multilayer exhibits p-type conductivity with a very low resistivity of $0.052\;\omega{cm}$, a high carrier concentration of $6.2X10^{19}\;cm^{-3}$ and a Hall mobility of $1.8\;cm^2/Vs$. We also observed a clear decrease of the resistivity in samples after low temperature annealing.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1542-1545
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• 2005

Transparent conducting aluminum-doped zinc oxide (AZO) thin films have been deposited on corning 1737 glass by DC magnetron sputter. The structural, electrical and optical properties of the films were investigated as a function of various substrate temperatures. AZO thin films were fabricated by dc magnetron sputtering with AZO ceramic target $(Al_2O_3: 2wt %)$. The obtained films were poly crystalline with a hexagonal wurtzite structure and preferentially oriented in the (002) crystallographic direction. The lowest resistivity is $6.0{\times}10^{-4}$ Ocm with the carrier concentration of $2.694{\times}10^{20}\;cm^{-3}$ and Hall mobility of $20.426cm^2/Vs$. The average transmittance in the visible range was above 90%.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1546-1549
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• 2005

Al-doped ZnO (ZnO:Al) thin films were grown on corning 1737 glass substrates by dc magnetron sputtering. The structural, electrical and optical properties of the films were investigated as a function of various discharge power. The obtained films were polycrystalline with a hexagonal wurtzite structure and preferentially oriented in the (002) crystallographic direction. The lowest resistivity is $6.0{\times}10^{-4}$ Ocm with the carrier concentration of $2.694{\times}10^{20}$ $cm^{-3}$ and Hall mobility of $20.426cm^2/Vs$. The average transmittance in the visible range was above 90%.