In this study, we investigated the electrical stability and performance enhancement of In₂O₃ thin-film transistors (TFTs) through hydrogen peroxide (H₂O₂) and ultraviolet (UV) treatment under controlled temperature conditions. The In₂O₃ TFTs were fabricated using a sol-gel process, followed by H₂O₂ treatment at 40, 50, and 60℃ in combination with UV irradiation. The impact of these processing conditions on the device characteristics, including mobility (μ), threshold voltage (Vth), subthreshold swing (S/S), and on/off current ratio, was systematically analyzed. The results indicate that the 50℃ TFTs exhibited the most stable electrical performance, with minimal Vth shift under negative bias stress (NBS) conditions and optimized switching behavior. Furthermore, static inverter measurements confirmed the reliable voltage transfer characteristics (VTCs) and gain performance of the optimized In₂O₃ TFTs. These findings suggest that the proposed H₂O₂ and UV treatment technique can effectively improve the reliability and long-term stability of In₂O₃-based electronic devices, making them promising candidates for future electronic applications.

The SiO₂/TiO₂ multilayer thin films used for narrow band pass filter were fabricated using E-beam evaporation method. The narrow band pass filter was used to enhance the resolution of spectroscopy and sensor applications with near infrared (NIR) light source. The narrow band pass filter with multilayer thin films were designed with Essential Macleod program. The multilayers of SiO₂/TiO₂ with 32 layers were deposited on the silicon encapsulation of IR with peak wavelength (λp) of 660 nm and NIR LEDs with λp of 830 nm, 880 nm, and 955 nm. After NIR light passed through the narrow band pass filter, the full width of half maximum of 33.4~48.6 nm became narrow to 20~24 nm owing to the absorption of photons with short or long wavelength of designed band of 20 nm. The SiO₂/TiO₂ band pass filter fabricated in this study can be used for sensor, optoelectronics, and NIR spectroscopy applications.

CNT fiber has been in the spotlight as a conductor, but the conductivity of CNT fibers do not match that of CNT. This study reveals that the conductivity of CNT fiber can be improved by depositing Al/Cu through vacuum evaporation. Cu is commonly used for deposition on CNT fibers. But low bonding strength of the interface between CNT and Cu could be a disadvantage. To overcome this, Al was deposited on the CNT fiber for forming aluminum carbide islands to increase the interfacial bonding strength. The conductivity characteristics were improved as the deposition time increased. The resistance was measured as a function of temperature, demonstrating that the temperature coefficient of resistance (TCR) is improved to be 241 ppm/℃ in comparison with that of as-received CNT fibers at -1,251 ppm/℃, when the CNT fibers are deposited with Al and Cu, respectively, for 90s and for 540s.

The phase change memory material is an active element in phase change memory and exhibits reversible phase transition behavior by thermal energy input. The doping of the phase change memory material with Ga leads to the increase of its crystallization temperature and the improvement of its amorphous stability. In this study, we investigated the effect of GaGe sputtering power on the formation of the phase change memory material including Ga. The deposition rate linearly increased to a maximum of 127 nm and the surface roughness remained uniform as the GaGe sputtering power increased in the range from 0 to 75 W. The Ga concentration in the thin film material abruptly increased at the critical sputtering power of 60 W. This influence of GaGe sputtering power was confirmed to result from a combined sputtering-evaporation process of Ga occurring due to the low melting point of Ga (29.77℃).

Electrode pattern effects on the capacitive humidity sensor were investigated. The fabrication of the capacitive humidity sensor was formed with three steps. The bottom electrode was formed on the silicon substrate with Pt/Ti thin layer by using shadow mask and e-beam evaporator. The photosensitive polyimide was formed on the bottom electrode by using photolithography process as a humidity sensitive thin film. The upper electrode was formed on the polyimide thin film with Pt/Ti thin layer by using e-beam evaporator and lift-off method. Three electrode patterns, such as circle, square, and triangle pattern, were used and changed the sizes to investigate the effects. The capacitances of the sensors were decreased 622 to 584 pF with the area decreament of patterns 250,000 to 196,250 μm2. From these results, a capacitive humidity sensor with photo sensitive polyimide is expected to be applied to a high sensitive humidity sensor.

ZnO crystals with different morphologies were synthesized through a thermal evaporation of Zn-Mn mixtures in air. The morphology was dependant on the Mn content in Zn-Mn mixture. The morphology was changed from rod to tetrapod shape with decreasing Mn content in Zn-Mn mixture. There sult indicates that the concentration of Mn might be responsible for the different morphologies of ZnOcrystals. XRD spectra showed that the ZnO crystals had a hexagonal wurtzite crystal strutures. For all the samples, room temperature cathodoluminescence spectra showed a ultra-violet emission at 380 nm and a green emission at around 500 nm. However, the intensity ratio of ultra-violet emission to green emission was significantly different with the Mn content in the source material.

Tubular-shaped ZnO crystals were synthesized by thermal evaporation technique under air atmosphere. Mixture of Zn and Mg powder was used as the source material. The thermal evaporation and oxidation of Zn/Mg mixture were carried out for 1 hr at 1,000℃ and 1,200℃ under in air under atmospheric pressure. When only Zn powder was used as a source material, tetrapod-shaped ZnO crystals were synthesized. This provides that Mg played a key role in the formation of the tubular-shaped crystals. SEM images showed that the tubular-shaped ZnO crystals grew along [0001] direction. XRD spectrum revealed that the ZnO tubes had hexagonal wurtzite structure. Two emission peaks at 380 nm and 510 nm were observed in the room temperature cathodoluminescence spectrum.

In this paper, we prepared Cu(In,Ga)Se2 thin films by using co-evaporation method, and analyzed the properties of the thin films. During the thin film preparation process, we confirmed InGaSe2 phase was formed at 400℃ in first stage, and also confirmed the thin films showed the vacancy decrease. In second and third stage,we confirmed the density increase of crystalline structure at over 480℃ and the formation of Cu(In0.7Ga0.3)Se2phase. As the result of SEM and XRD analysis of the films which were before and after heat-treated, we confirmed the disappearance of Cu2Se2 and the formation of Cu(In0.7Ga0.3)Se2 single phase after the heat-treatment,We, therefore, confirmed the heat-treatment did not affect the absorbency spectra of the thin films.

ZnO crystals with octahedral shape were synthesized by thermal evaporation technique. ZnF2 powder was used as the source material. The thermal evaporation and oxidation of ZnF2 powder was carried out for 1 hr at 1,000℃ in air under atmospheric pressure. SEM images showed that the ZnO crystals produced by oxidizing ZnF2 vapor possessed a characteristic octahedral shape. XRD spectrum revealed that the ZnO octahedron had hexagonal wurtzite structure. In the room temperature photoluminescence spectrum, a strong green emission peak at around 510 nm was observed.

The effect of oxygen pressure in the synthesis of ZnO nanostructures through thermal evaporation of Zn powder was investigated. The thermal evaporation process was carried out in oxygen ambient for 1 hr at 1,000℃ under different pressures. The oxygen pressure was changed in range of 0.5 ? 900 Torr. Any nanostructure was not formed on the specimens prepared at oxygen pressures lower than 10 Torr. When oxygen pressure was 100 Torr, ZnO nanowires were observed. With increasing the oxygen pressure to 500 Torr, the morphology of ZnO nanostructures changed from wire to tetrapod. For all the samples, room temperature photoluminescence spectra show a strong green emission peak at around 550 nm.

The prepartion of various metal oxide nanostructures via hydrothermal method, hydrolysis, thermal evaporation and electrospinning and their applications to chemoresistive sensors have been investigated. Hierarchical and hollow nanostructures prepared by hydrothermal method and hydrolysis showed the high response and fast responding kinetics on account of their high gas accessibility. Thermal evaporation and electrospinning provide the facile routes to prepare catalyst-loaded oxide nanowires and nanofibers, respectively. The loading of noble metal and metal oxide catalyst were effective to achieve rapid response/recovery and selective gas detection.

ZnO nanostructures were developed on a Si (100) substrate from powder mixture of ZnO and 5 mol% Pd (ZP-5) as reactants by × sccm oxygen pressures(x= 0, 10, 20, 40). DTA (differential thermal analysis) result shows the Pd(5 mol%)+ZnO mixtured powder(PZ-5) is easily evaporated than pure ZnO powder. The PZ-5 mixtured powder was characterized by DTA to determine the thermal decomposition which was found to be at 800℃, 1,100℃. Weight loss(%) and ICP (inductively coupled plasma) analysis reveal that Zn vaporization is decreased by increased oxygen pressures from the PZ-5 at 1,100℃ for 30 mins. Needle-like ZnO nanostructures array developed from 10 sccm oxygen pressure, was well aligned vertically on the Si substrate at 1,100℃ for 30 mins. The lengths of the Needle-like ZnO nanostructures is about 2 μm with diameters of about 65 nm. The developed ZnO nanostructures exhibited growth direction along [001] with defect-free high crystallinity. It is considered that Zn vaporization is responsible for the growth of Needle-like ZnO nanostructures by controlling the oxygen pressures. The photoluminescence spectra of ZnO nanostructures exhibited stronger 376.7 nm NBE (near band-edge emission) peak and 529.3 nm DLE (deep level energy) peak.

Cu(In1-x,Gax)Se2 thin films have been considered as an effective absorber material for high efficient solar cells. In this paper, the CIGS thin films with varied Ga content were prepared using a co-evaporation process of three stage. We carry out structure and electrical optical property on the thin film in varied Ga content. CIGS thin films have been characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), energy-dispersive spectroscopy(EDS), four-point probe measurement, and the Hall measurement. To optimize Ga contents, Ga/(In+Ga) ratio were changed from 0.13 to 0.72. At this time the carrier concentrations were varied from 1.22×10(11) cm-3 to 5.07×10(16) cm-3, and electrical resistivity were varied from 1.11×10(0) Ω-cm to 1.08×10(2) Ω-cm. A strong <220/204> orientation and a lager grain size were obtained at a Ga/(In+Ga) of 0.3. We were able to achieve conversion efficiency as high as 15.95% with a Ga/(In+Ga) of 0.3.

In this paper, CuInSe2 thin film was prepared by use of the co-evaporation method with the variation of the substrate temperature in the range of 100℃ to 400℃. The film was annealed at 300℃ for an hour in a vacuum chamber at 3×10-4 Pa. After annealing, the thin film prepared at the substrate temperatures of 100℃ and 200℃ was observed. The XRD (x-ray diffraction) pattern of sample prepared at 100℃ showed the single phase formation of CuInSe2. However, at 200℃, there was no apparent difference in the XRD pattern except a variation in the intensity of the peak. As the annealing treatment of substrate improved the crystal structure of the film, it affected to the increase of an electron mobility, resulted in an increase in conductivity and a decrease in resistance. As a results, when the substrate temperature was at 200℃ and 300℃, the sheet resistance was 1.534 n/and 1.554 n/, respectively, and the resistivity was 1.76×10-6 n·㎝ and 1.7210-6 n·㎝, respectively. From the absorption spectrum measurements, there was no variation between the before and after annealing conductions. And it means that the annealing step does not affect the thickness of the thin film.

CdSe films were deposited on glass substrates (CdSe/glass) by thermal evaporation. Substrate temperature was lowered by cooling substrate holder with liquid nitrogen. Substrate temperatures were 200℃, 0℃ and -40℃. The crystallographic properties and surface morphologies of the CdSe/glass films were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The optical and electrical properties of the films were investigated by dependence of energy gap, photosensitivity and resistivity on the substrate temperature. CdSe/glass showed energy gap of ～1.72 eV regardless of substrate temperature. The resistivity of the films decreased to 0.5 Ωcm by lowering the substrate temperature to -40℃. The CdSe/glass films prepared at 0℃ showed the highest photosensitivity among the films in this study.