• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.7
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• pp.494-498
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• 2003

In this paper, the plasma treatment on gate surface has been applied prior to deposition of pentacene and the effects on performance were investigated. The Plasma treatment produced the mobility of 0.05$\textrm{cm}^2$/V.sec which is 10 times larger than the non-treated. The resistance was also reduced from 400K$\Omega$ to 50K$\Omega$. In addition, the standard deviation of performance parameters variation was reduced with the plasma exposure time, which implies that plasma treatment makes the gate surface states be uniform across the whole wafer area. The performance parameters were increased with the exposure time up to 5min, after which they degraded again. Therefore, the optimal exposure time was found to be 5min.

• Journal of the Korean Ceramic Society
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• v.40 no.3
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• pp.262-267
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• 2003

The heteroepitaxial ZnO thin film on sapphire (0001) substrate was prepared by an off-axis Radio Frequency(RF) magnetron sputtering. The crystallinity of ZnO thin film was affected by deposition pressure, RF power, and substrate temperature. High quality heteroepitaxial ZnO thin film was obtained when the kinetic energy of sputtered particles is well harmonized with the surface mobility. In the result of Photoluminescence(PL) of heteroepitaxial ZnO thin film, Ultraviolet(UV) emissions at 3.36 and 3.28 eV were observed at low(17 K) and Room Temperature(RT). respectively. As the ZnO thin film was annealed in O$_2$ambient, the crystallinity was improved while UV emission was drastically decreased.

• Journal of the Korean institute of surface engineering
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• v.52 no.6
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• pp.342-349
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• 2019

Titanium nitride(TiN) thin films have been deposited on PEN(Polyethylene naphthalate) substrate by reactive RF(13.56 MHz) magnetron sputtering in a 25% N₂/Ar mixed gas atmosphere. The pulsed DC bias voltage of -50V on substrates was applied with a frequency of 350 kHz, and duty ratio of 40%(1.1 ㎲). The effects of pulsed DC substrate bias voltage on the crystallinity, color, electrical properties of TiN_x films have been investigated using XRD, SEM, XPS and measurement of the electrical properties such as electrical conductivity, carrier concentration, mobility. The deposition rates of TiN_x films was decreased with application of the pulsed DC substrate bias voltage. The TiN_x films deposited without and with pulsed bias of -50V to substrate exhibits gray and gold colors, respectively. XPS depth profiling revealed that the introduction of the substrate bias voltage resulted in decreasing oxygen concentration in TiN_x films, and increasing the electrical conductivities, carrier concentration, and mobility to about 10 times, 5 times, and 2 times degree, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.4
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• pp.267-273
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• 1998

The band structures of $Si_{1-x}Ge_x$ layers grown on $Si_{1-y}Ge_y$ substrate are calculated using k$\cdot$p and strain Hamiltonians. The hole drift mobilities in the plane direction are then calculated by taking into account the screening effect and the density-of-states of the impurity band. When $Si_{1-x}Ge_x$ is grown on Si substrate, the mobilities of (110) and (111) $Si_{1-x}Ge_x$ layers are larger than that of (001) $Si_{1-x}Ge_x$. However, due to the large defect and surface scattering, (110) and (111) $Si_{1-x}Ge_x$ layers may not be useful for the development of the fast device. Meanwhile, when Si is grown on $Si_{1-y}Ge_y$ substrate, the mobilities of (001) and (110) Si layers are greatly enhanced. Based on the amount of defect and the surface scattering, it is expected that Si grown on (001) $Si_{1-y}Ge_y$ substrate, where the Ge contents is larger than 10%(y>0.1), has the highest mobility.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.333-334
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• 2007

This paper describes the characteristics of poly (polycrystalline) 3C-SiC grown on SiOz and AlN substrates, respectively. The crystalline quality of poly 3C-SiC was improved from resulting in decrease of FWHM (full width half maximum) of XRD by increasing the growth temperature. The minimum growth temperature of poly 3C-SiC was $1100^{\circ}C$. The surface chemical composition and the electron mobility of poly 3C-SiC grown on each substrate were investigated by XPS and Hall Effect, respectively. The chemical compositions of surface of poly 3C-SiC films grown on $SiO_2$ and AlN were not different. However, their electron mobilities were $7.65\;cm^2/V.s$ and $14.8\;cm^2/V.s$, respectively. Therefore, since the electron mobility of poly 3C-SiC films grown on AlN buffer layer was two times higher than that of 3C-SiC/$SiO_2$, a AlN film is a suitable material, as buffer layer, for the growth of poly 3C-SiC thin films with excellent properties for M/NEMS applications.

• Korean Journal of Materials Research
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• v.15 no.9
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• pp.604-607
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• 2005

Dependence of the crystallinity, surface roughness, carrier concentration, carrier mobility, electrical resistivity and transmittance of Al-doped ZnO films deposited on glass substrates by RF-magnetron sputtering on effects of the ratio of the RF power for AlZnO to that for ZnO (R) have been investigated. X-ray diffraction spectra show strong preferred orientation along the c-axis. The full width at half maximum (FWHM) of the ZnO (002) peak decreases slightly as R increases in the range of R<1.0, whereas it increases substantially in the range of R>1.0. Scanning electron micrographs (SEM) show that the ZnO film surface becomes coarse as R increases. The carrier concentration and the carrier mobility in the ZnO thin film are maximal for R=1.5 and 1.0, respectively. The electrical resistivity is minimal for R=1.0 The transmittance of the ZnO:Al film tends to increase, but to decrease slightly in the range of R>0.5. It may be concluded that the optimum R value is 1.0, considering all these analysis results. The cause of the changes in the structure and physical properties of ZnO thin films with R are also discussed.

• Journal of Soil and Groundwater Environment
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• v.20 no.6
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• pp.133-139
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• 2015

Attention to munitions constituents such as 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in the firing ranges is increasing due to their toxicity and high mobility to the environment. It is helpful to use a systemic model to predict the amount of contaminants for the establishment of environmental management of firing ranges. This study employed Training Range Environmental Evaluation and Characterization System (TREECS) program to estimate the mobility characteristics of TNT and RDX via groundwater leaching, soil erosion and surface water runoff. The prediction results of the TNT and RDX migration with TREECS showed that 68% of initial TNT and 21% of initial RDX were discharged through the soil erosion and the 20% of initial TNT and 54% of initial RDX ran out the firing range via the groundwater leaching. The rest of the initial TNT and RDX moved to adjacent surface water via surface runoff. The data suggest that soil erosion and surface runoff occupying 80% of TNT to the total amount are important migration pathways. On the other hand, groundwater leachning occupying 54% to the total amount was also important pathway for RDX.

• Journal of Soil and Groundwater Environment
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• v.20 no.6
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• pp.28-36
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• 2015

Simultaneous mobility reduction of explosives and heavy metals in an operational range by monopotassium phosphate (MKP) and bentonite spreading technology was investigated. Potassium ion and phosphate ion in MKP act as explosives sorption enhancer and insoluble heavy metal phosphate formation, respectively, while bentonite acts as the explosives adsorbent. Then, the decrease in surface water concentration of the pollutants and resulting risk reduction for local residents of the operational range, by MKP/bentonite application was estimated. Under untreated scenario, the noncancer hazard index (HI) exceeded unity on February, July and August, mainly due to 2,4,6-trinitrotoluene (TNT); however, MKP/bentonite treatment was expected to lower the noncancer hazard index by decreasing the surface water concentration of explosives and heavy metals (especially TNT). For example, on July, estimated surface water concentration and HI of TNT were 0.01 mg/L and 1.1, respectively, meanwhile the sorption coefficient of TNT was 3.9 mg¹⁻ⁿkg⁻¹Lⁿ. However, by MKP/bentonite treatment, the TNT sorption coefficient increased to 113.8 mg¹⁻ⁿkg⁻¹Lⁿ and the surface water concentration and HI decreased to about 0.002 mg/L and 0.2, respectively. Based on the result, it can be concluded that MKP/bentonite spreading is a benign technology that can mitigate the risk posed by the pollutants migration from operational ranges.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.6
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• pp.588-593
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• 2023

The advantage of OTFT technology is that large-area circuits can be manufactured on flexible substrates using a low-cost solution process such as inkjet printing. Compared to silicon-based inorganic semiconductor processes, the process temperature is lower and the process time is shorter, so it can be widely applied to fields that do not require high electron mobility. Materials that have utility as electrode materials include carbon that can be solution-processed, transparent carbon thin films, and metallic nanoparticles, etc. are being studied. Recently, a technology has been developed to facilitate charge injection by coating the surface of the Al electrode with solution-processable titanium oxide (TiOx), which can greatly improve the performance of OTFT. In order to commercialize OTFT technology, an appropriate method is to use a complementary circuit with excellent reliability and stability. For this, insulators and channel semiconductors using organic materials must have stability in the air. In this study, carbon-doped Mo (MoC) thin films were fabricated with different graphite target power densities via unbalanced magnetron sputtering (UBM). The influence of graphite target power density on the structural, surface area, physical, and electrical properties of MoC films was investigated. MoC thin films deposited by the unbalanced magnetron sputtering method exhibited a smooth and uniform surface. However, as the graphite target power density increased, the rms surface roughness of the MoC film increased, and the hardness and elastic modulus of the MoC thin film increased. Additionally, as the graphite target power density increased, the resistivity value of the MoC film increased. In the performance of an organic thin film transistor using a MoC gate electrode, the carrier mobility, threshold voltage, and drain current on/off ratio (I_on/I_off) showed 0.15 cm²/V·s, -5.6 V, and 7.5×10⁴, respectively.

• Journal of Information Display
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• v.6 no.2
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• pp.16-18
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• 2005

Hybrid insulator pentacene thin film transistors (TFTs) are fabricated with thermally grown oxide and cross-linked polyvinylalcohol (PVA) including surface treatment by dilute ploymethylmethacrylate (PMMA) layer on $n^+$ doped silicon wafer. Through the optimization of $SiO_2$ layer thickness in hybrid insulator structure, carrier mobility is increased to more than 35 times than that of the TFT which has only a gate insulator of $SiO_2$ at the same electric field. The carrier mobility of $1.80cm^2$/V-s, subthreshold swing of 1.81 V/decade, and $I_{on}/I_{off}$ current ratio> $1.10{\times}10^5$ are obtained less than -30 V bias condition. The result is one of the best reported performances of pentacene TFTs with hybrid insulator including cross-linked PVA layer as a gate insulator at relatively low voltage operation.