Gwangpyo Choi

Growth and Surface Morphology of Textured NiO Thin Films Deposited by Off-Axis RF Magnetron Sputtering

Textured crystalline NiO thin films were grown on Si(100) substrates by off-axis RF magnetron sputtering without substrate heating using a NiO target. (100)-textured NiO films were obtained using pure Ar gas. On the other hand, (111)-textured NiO films were obtained using pure O2 gas. Also, the surface morphology and roughness of the NiO thin films were closely related to the type of sputtering gas and RF power.

Characteristics of Pd-doped WO 3 thin film for hydrogen gas sensor

Physicochemical and electrical properties for hydrogen gas sensors based on Pd-deposited thin films were investigated as a function of Pd thickness, annealing temperature, and operating temperature. thin films were deposited on an insulating material by thermal evaporator. XRD, FE-SEM, AFM, and XPS were used to evaluate the crystal structure, microstructure, surface roughness, and chemical property, respectively. The deposited films were grown polycrystalline with rhombohedral structure after annealing at . The addition effect of Pd is not the crystallinity but the suppression of grain growth of . Pd was scattered an isolated small spherical grain on thin film after annealing at and it was agglomerated as an irregular large grain or diffused into after annealing at . 2 nm Pd-deposited thin films operated at showed good response and recovery property.

Potentiometric CO 2 gas sensor based on the thin film electrolyte of Li + ion conductor

Li+-ion conducting () thin films with thickness of , , were deposited on substrate at room temperature by thermal evaporation. They were sintered at and for 2 hours, respectively. Reference electrode and sensing electrode were printed on Au-electrode by silk printing method. The EMF and the /dec were increased with increasing the electrolyte thickness and sintering temperature. The sample sintered at was shown a good response and recovery characteristics more than those sintered at . The Nernst`s slop of 75 mV per decade was obtained at operating temperature of .