The Effect of Annealing Treatment on n-Cu2O Thin Film Fabrication

This experiment is about fabrication of homojunction n-type cuprous oxide (Cu2O) thin film by using electrodeposition method. The Cu2O thin films were deposited on fluorine doped tin oxide (FTO) substrates by using copper acetate based solution through potentiostatic electrodeposition method. The n-type Cu2O was fabricated at pH 6.3 with a fixed potential of -0.125V vs. Ag/AgCl and time deposition of 30 minutes. Annealing treatment was introduced to enhance the properties of the thin films.  The quality of Cu2O thin films were studied in varied the annealing duration. Morphological, structural, optical and electrical properties were characterized using X-Ray Diffractometer, Field Emission-Scanning Electron Microscopy, Ultraviolet-visible Spectroscopy and Four Point Probe, respectively

The Effect of pH Solution on Electrodeposit-N-Cu2O Thin Film

n-type semiconducting Cu2O thin film was successfully prepared on FTO coated glass substrate using electrodeposition method. The effect of pH solution was studied in order to optimize the deposition parameters of n-Cu2O. The solution was prepared using copper acetate and acid lactic. The pH solution was accurately adjusted using potassium hydroxide and varied from 3.5 until 6.5. The n-Cu2O was successfully deposited at higher pH solution from 5.5 until 6.5. Moreover, it showed excellent structural characteristic and good morphology properties. The Cu2O was adsorbed light at approximately 600 nm corresponding to the bandgap of 2.0 eV. The successful fabrication of n-Cu2O was confirmed and the significant effect of pH solution was observed

Annealing Treatment on Homogenous n-TiO2/ZnO Bilayer Thin Film Deposition as Window Layer for p-Cu2O-Based Heterostructure Thin Film

Metal oxide semiconductor material has great potential to act as window layer in p–n heterojunction solar cell thin film owing to low production cost and significant properties in photo-voltaic mechanism. In this work, n-TiO2/ZnO bilayer thin film was effectively constructed by means of sol-gel spin coating technique in an effort to diminish the electron-hole recombination rate from single-layered thin film. Annealing time is one of the important parameters in the fabrication process and was varied to study the impact of annealing treatment towards the thin film characteristics as window layer. It was found that the optimum parameter for the n-TiO2/ZnO bilayer was 500 °C with an annealing time of 2 h. High crystallinity of the n-(101)-TiO2/(002)-ZnO bilayer thin film was obtained, which consists of anatase and a hexagonal wurtzite structure, respectively. Orientation of (002)-ZnO is essential for deposition with the (111) Cu2O-absorbing layer due to a low different lattice mismatch between these two interfaces. The homogenous morphology of n-TiO2/ZnO bilayer was observed with a compact and dense layer. The improvement of transmittance has also been achieved in a range of 60%–80%, which indicated that the incident light can penetrate throughout the thin film directly. In addition, a p-Cu2O absorbing layer was successfully fabricated on top of n-TiO2/ZnO bilayer thin film to form a p-n junction in order to visualize significant electrical rectification properties. The existence of p-Cu2O was confirmed by a (111)-peak orientation and triangular shape in structural and morphological properties, respectively

High temperature fracture toughness and fatigue behavior of ti-zr-mo and w-re alloys for x-ray tube application

Commercial x-ray targets for computed tomography (CT) applications consist of two major components, a metal disc made of the titanium-zirconium-molybdenum (TZM) alloy, and a surface layer in the bombarding region made of the tungsten-rhenium (W-Re) alloy. The target must endure extremely high temperature, associated with high thermal stress, and mechanical stress due to the centrifugal force induced by high speed rotation of the target. Therefore, studies on high temperature fracture and fatigue behavior of these materials would be the most important for reliability assessment and safety design of the x-ray target. However, they have been rarely reported and high temperature fracture and fatigue behavior of these materials has been not always clarified. In the present study, high temperature fracture toughness was evaluated for two kind of TZM alloys, one with higher C content and the other with higher O content. Moreover, effect of forging rate on high temperature fracture toughness was discussed. Fatigue properties at room temperature and 1000 °C were evaluated for three kinds of materials, layered W-Re/TZM, bulk W-Re and bulk TZM, and a fatigue failure definition in the high temperature fatigue test was investigated to evaluate high temperature fatigue strength. The fatigue processes of these x-ray target materials at high temperature were also investigated. High temperature fracture toughness of two TZM alloys with different kinds of grain boundary particles was successfully evaluated using the convenient JIC test method. The result indicated that the JIC values at temperatures ranged from 800 °C to 1000 °C were almost constant regardless of temperature, while the JIC values of the TZM with higher C content were higher than those of the TZM with higher O content. The TZM with different forging rates showed similar JIC values, which suggested the effect of forging rate would be not significant at high temperatures. High temperature fatigue characteristics of W-Re and TZM were successfully evaluated under load-controlled four point bending test at 1000 °C by introducing a fatigue failure criterion as two-times increase of initial compliance, which was corresponding to nucleation and propagation of multiple cracks from specimen surface. The layered W-Re/TZM specimen exhibited the similar fatigue strength to the bulk W-Re specimen. The bulk TZM showed much lower fatigue strength compared to the layered W-Re/TZM and the bulk W-Re. The total crack length measured on the specimen surface at 1000 °C would be a dominant indicator for evaluating progress of fatigue damage

Annealing Treatment on Homogenous n-TiO2/ZnO Bilayer Thin Film Deposition as Window Layer for p-Cu2O-Based Heterostructure Thin Film

Metal oxide semiconductor material has great potential to act as window layer in p–n heterojunction solar cell thin film owing to low production cost and significant properties in photo-voltaic mechanism. In this work, n-TiO2/ZnO bilayer thin film was effectively constructed by means of sol-gel spin coating technique in an effort to diminish the electron-hole recombination rate from single-layered thin film. Annealing time is one of the important parameters in the fabrication process and was varied to study the impact of annealing treatment towards the thin film characteristics as window layer. It was found that the optimum parameter for the n-TiO2/ZnO bilayer was 500 °C with an annealing time of 2 h. High crystallinity of the n-(101)-TiO2/(002)-ZnO bilayer thin film was obtained, which consists of anatase and a hexagonal wurtzite structure, respectively. Orientation of (002)-ZnO is essential for deposition with the (111) Cu2O-absorbing layer due to a low different lattice mismatch between these two interfaces. The homogenous morphology of n-TiO2/ZnO bilayer was observed with a compact and dense layer. The improvement of transmittance has also been achieved in a range of 60%–80%, which indicated that the incident light can penetrate throughout the thin film directly. In addition, a p-Cu2O absorbing layer was successfully fabricated on top of n-TiO2/ZnO bilayer thin film to form a p-n junction in order to visualize significant electrical rectification properties. The existence of p-Cu2O was confirmed by a (111)-peak orientation and triangular shape in structural and morphological properties, respectively