Surface Morphology and Sensing Property of NiO-WO3 Thin Films Prepared by Thermal Evaporation

Sensors

Dong-myong Na²  L. Satyanarayana³  Gwang-Pyo Choi¹  Yong-Jin Shin⁴ 

[1] JAMIC, Sunchun, Jeonnam 540-856, Korea;Department of Advanced Materials and Engineering, Chosun University, Gwangju 501-759, Korea;Research Institute of Energy Resources Technology, Chosun University, Gwangju 501-759, Korea;Department of Physics, Chosun University, Gwangju 501-759, Korea

关键词: Tungston Oxide;    Thin films;    Thermal evaporation;    surface morphology;   

DOI  :  10.3390/s5120519

来源: mdpi

【 摘 要 】

WO₃ and NiO-WO₃ thin films of various thicknesses were deposited on an Al₂O₃-Si (alumina-silicon) substrate using high vacuum thermal evaporation. After annealing at 500°C for 30 minutes in air, the crystallanity and surface morphology of WO₃ and NiO-WO₃ thin films were investigated using X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). It is observed that the WO₃ thin films were resulted in cracks between the polycrystalline grains and the grain growth was increased with increasing thickness causing deteriorated sensing characteristics of the films. On the other hand, an optimum deposition of NiO on WO₃ thin film has inhibited the grain growth and improved the sensitivity of the films. The inhibition is limited to a certain thickness of WO₃ and NiO content (mol %) of inclusion and below or above this limitation the grain growth could not be suppressed. Moreover, the deposition sequence of NiO and WO₃ is also playing a significant role in controlling the grain growth. A probable mechanism for the control of grain growth and improving the sensing property has been discussed.

【 授权许可】

Unknown   
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