The development of a large-area solution process for CuO nanowires, which are promising p-type thin film transistors (TFT) channel materials, is required. To overcome the limitations of the existing high-vacuum and high-cost deposition process, a large-area Cu nanowire network was formed on the substrate using the Mayer rod coating method, and a CuO channel was implemented by subsequent thermal annealing. Consequently, p-type TFT with an on/off current ratio of 1.4×10⁴ and a field-effect mobility µ_FE≈10^-4 cm²/(V⋅s). was fabricated and optimized. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses showed that the sample annealed at 200°C exhibited an incomplete oxidation state with a mixed Cu/Cu₂O phase and a high fraction of M-OH species (58.78%), resulting in a low on/off current ratio (≈1.2). In contrast, annealing at 450°C leads to a CuOdominant phase, where the fraction of lattice oxygen(O1) increases to 31.11% and the oxygen vacancy (VO) component increases to 7.15%, indicating a significant improvement in hole concentration and charge transport. These phase transitions and surface chemical changes are identified as the key mechanisms for the enhanced TFT switching characteristics. The low-cost, large-area Mayer rodbased solution process proposed in this study provides a basic process platform for p-type TFTs applicable to flexible wearables and display technologies and suggests the possibility of commercialization through additional optimization of bias stability in the future.

In this study, the following results were obtained by analysis of electric properties with FT-IR, DSC, XRD, and SEM, in the range of temperature 30~160℃ and frequency 0.1~200 kHz, when filling agent (0~100 phr) and silicone oil (0~12 phr) were added to raw silicone rubber. In the case of 100 phr mixed samples, the relative dielectric constant εr gradually decreased from 4.3 to 3.96 as frequency increased, and the dielectric loss tan δ decreased to 0.01 at 300 Hz, then increased to 0.022 at 30 kHz, then decreased to 200 kHz. The FT-IR analysis identified the same binding structure according to the chemical composition of added silica (SiO₂). Through DSC analysis, we could determine the change of heat quantity and the glass transition temperature of each specimen. In the XRD analysis, it was found that the images SiO₂, TiO₂, and Fe₂O₃ appeared for specimens with 0%, 50% and 100% filling agent. Finally, the SEM analysis confirmed that particles of 0.5 to 1.5 μm size with silica (SiO₂) mixing were dispersed evenly.

Methylammonium lead triiodide (MAPbI₃)-based perovskite solar cells potentially have potential advantages such as high efficiency and low-cost manufacturing procedures. However, MAPbI₃ is structurally unstable and has low phase-change temperatures (30°C and 130°C); it is necessary to solve these problems. We investigated the crystal structure and phase separation using real-time temperature-change X-ray diffraction, transmission electron microscopy, and electron energy loss spectroscopy. MAPbI₃ has a tetragonal structure, and at about 35°C the c-axis contracts, transforming MAPbI₃ into the related cubic crystal structure. In addition, at 130°C, phase separation occurs in which CH₃NH₂ and HI at the center of the unit cell of the perovskite structure are extracted by gas, leavingand only PbI₂ of the three-component structure, is produced as the final solid product.

Thermal and structural stability in the glass transition region of chalcogenide glasses has been investigated in terms of thermodynamics for application to various optoelectronic devices. In this study, the compositions of Ge_xSb₂₀Se_80-x (x = 10, 15, 20, 25, and 30) were selected to investigate the glass stability according to germanium ratios. The chalcogenide bulks were fabricated by using a traditional melt-quenching method. Thin films were deposited by a thermal evaporation system, maintaining the deposition ratio of 3~5 A in order to have uniformity. The thermal and structural properties were measured by a differential scanning calorimeter (DSC) and X-ray diffraction (XRD). The DSC analysis provided thermal parameters and theoretical glass region stabilities. The XRD analysis supported the theoretical stabilities because of where the crystallization peak data occurred.

Citations

• Characteristics of Heavy Metal Oxide Glasses in BaO-GeO2-La2O3-ZnO-Sb2O3 System for Infrared Lens
  Sang-Jin Park, Bok-Hyun Oh, Sang-Jin Lee
  Korean Journal of Materials Research.2023; 33(10): 414.     CrossRef

Bottom-gate tin oxide (SnO2) thin film transistors (TFTs) were fabricated on N+ Si wafersused as gate electrodes. 60-nm-thick SnO2 thin films acting as active layers were sputtered onSiO2/Al2O3 films. The SiO2/Al2O3 films deposited on the Si wafers were employed for gate dielectrics. Inorder to increase the resistivity of the SnO2 thin films, oxygen mixed with argon was introduced into thechamber during the sputtering. The mobility of SnO2 TFTs was measured as a function of the flow ratioof oxygen to argon (O2/Ar). The mobility variation with O2/Ar was analyzed through studies oncrystallinity, oxygen binding state, optical properties. X-ray diffraction (XRD) and XPS (X-rayphotoelectron spectroscopy) were carried out to observe the crystallinity and oxygen binding state ofSnO2 films. The mobility decreased with increasing O2/Ar. It was found that the decrease of the mobilityis mainly due to the decrease in the polarizability of SnO2 films.

Phase transition properties of the copolymer films of polyvinylidene fluoride (PVDF) and trifluoroethylene(TrFE), P(VDF-TrFE), were studied with X-ray diffraction (XRD) and polarization modulated ellipsometry (PME). XRD studies on both Langmuir-Blodgett (LB) films and spin coated films exhibit conversions from ferroelectric phase to paraelectric phase at 108±2℃ on heating and paraelectric phase to ferroelectric phase at 78±2℃ on cooling. The presence of the ferroelectric-paraelectric phase transition is also confirmed by the PME technique for the first time in this study. PME was proved to be a very sensitive tool in the measurement of the structural changes at the nano-thickness films.

Concern for the TOS (Transparent Oxide Semiconductor) is increasing with the recent increase in interest for flexible device. Especially MgZnO has attracted a lot of attention. MgxZn1-xO, which ZnO-based wideband-gap alloys is tuneable the band-gap ranges from 3.36 eV to 7.8 eV. In particular, the flexible substrate, the crystal structure of the amorphous as well as the surface morphology is not good. So research of MgZnO thin films growth on flexible substrate is essential. Therefore, in this study, we studied on the effects of the oxygen partial pressure on the structural and crystalline of Mg0.1Zn0.9O thin films. MgZnO thin films were deposited on PES substrate by using pulsed laser deposition. We used XRD and AFM in order to observe the structural characteristics of MgZnO thin films. UV-visible spectrophotometer was used to get the band gap and transmittance. Crystallization was done at a low oxygen partial pressure. The crystallinity of MgZnO thin films with increasing temperature was improved, Grain size and RMS of the films were increased. MgZnO thin films showed high transmittance over 80% in the visible region.

In this study, transparent conducting Al-doped Zinc Oxide (AZO) films with a thickness of 150 nm were prepared on corning glass substrate by the RF magnetron sputtering with using a Al-doped zinc oxide (AZO), (Al2o3: 2 wt%) target at room temperature. This study investigated the effect of rapid thermal annealing temperature and oxygen ambient on structural, electrical and optical properties of Al-doped zinc oxide (AZO) thin films. The films were annealed at temperatures ranging from 400 to 700℃ by using Rapid thermal equipment in oxygen ambient. The effect of RTA treatment on the structural properties were studied by x-ray diffraction and atomic force microscopy. It is observed that the Al-doped zinc oxide (AZO) thin film annealed at 500℃ at 5 minute oxygen ambient gas reveals the strongest XRD emission intensity and narrowest full width at half maximum among the temperature studied. The enhanced UV emission from the film annealed at 500℃ at 5 minute oxygen ambient gas is attributed to the improved crystalline quality of Al-doped zinc oxide (AZO) thin film due to the effective relaxation of residual compressive stress and achieving maximum grain size.

Perovskite niobates and tantalates have been placed on a short list of functional materials for future technologies. This article was investigated ferroelectric materials Ag(Ta,Nb)O3 thick film. In this study, we have fabricated the Ag(Ta,Nb)O3 thick film on the Al2O3 substrates by screen printing method. The Ag(Ta,Nb)O3 thick film were fabricated by the mixed oxide method. The sintering temperature and time were 1,150℃, 2 hr. The electrical properties of Ag(Ta,Nb)O3 thick film were investigated at 30∼100℃.

As a II-IV compound semiconductor, ZnO has a wide band gap of 3.37 eV with transparent properties. Due to this transparent properties, ZnO materials can be also employed as the transparent conducting electrode materials. Recently, rapid progress has been made in the field of DSSC (dye sensitized solar cell)area. Therefore, strong demands have been required for the transparent electrodes with low temperature processing and cheap cost. In this paper, we will prepare ZnO thick films on the PET substrates for the electrode applications. We will investigate the structural and microstructure properties through the XRD, and SEM analysis, respectively. Also, we will study the electrical of specimens to apply the conducting electrode.

The semiconducting material of ZnO in II-VI group was well known as its good application for photo electronics, chemical sensors and field effect transistors due to the remarkable optical properties with wide energy band gap and great ionic reactivities. Up to now the growth of a good quality of ZnO film has been issued for better performances. Even though there were many deposition methods for making ZnO films, pulse laser deposition methods have been preferred for high crystalline films. In this report, the ZnO film was also created by pulsed laser deposition technique which also showed high crystalinity. By controlling several factors when deposited, it was investigated that the optimal condition for ZnO film formation. Mainly, oxygen partial pressures and growth temperatures were changed when ZnO films were synthesized and followed the characterization by HRXRD and AFM.