The Effects of Non-Stoichiometry and Lithium Doping on the Performances of (Na0.5K0.5)NbO3 –Based Piezoelectric Thin Films Derived via Sol-Gel Methods

• Main Authors: Chan-ChingChen, 陳展慶
• Other Authors: Sheng-Yuan Chu
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/65034443530684820095

碩士 === 國立成功大學 === 電機工程學系 === 102 === In this study, lead-free non-stoichiometric piezoelectric (Na0.5K0.5)NbO3 (NKN) films were fabricated by sol-gel processing on Pt (111)/Ti/SiO2/Si(100) substrates. To investigate the microstructure and electrical properties of films, a serious of measurements such as XRD, SEM, AFM, J-V, XPS, P-E, d33, etc were carried out. It was found that the secondary phases and oxygen vacancies formed when sodium and potassium volatilized via annealing process. Then these secondary phases resulted in poor electrical properties. Therefore, the compensation of sodium and potassium appropriately is necessary. Besides, we tried to clarify the mechanism of current conduction more clearly. At last, the optimum excess mount of sodium and potassium on NKN film were found from this study. In addition to non-stoichiometric NKN film, lithium dopants are doped in our system to form Lix(Na0.5 K0.5)(1-x) NbO3 structure. The effects of lithium doping on the microstructures and electrical properties of the samples were investigated. Finally, we found the remnant polarization and piezoelectric coefficient were Improved effectively through doping lithium appropriately.