Properties of PLZT Ferroelectric Thin Films Prepared by Sol-Gel Technique

• Main Authors: Wu, Bing-Hsun, 吳秉勳
• Other Authors: Lin, Jing-Fung
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/53661338203817676546

碩士 === 遠東科技大學 === 機械工程研究所 === 99 === Ferroelectric films as PLZT have the characteristics of big electric conduction constant, strong self polarization, high electro-optic coefficient and good integration with semiconductor technique. Hence, integrated ferroelectrics and integrated optics especially have excellent applications in optic communications. This study is to adopt sol-gel method to manufacture the PLZT films, using ITO glass as substrate, considering with or without a seeding layer, trying different thickness of a seeding layer as PT or PLT, and also using sol-gel method to manufacture the upper SnO2 film. Finally, using two linear heterodyne interferometers to measure the electric-field-induced birefringence of the PLZT films including the principal axis angle and the retardance. Next, using a UV-VIS spectrometer to measure the transmittances of PLZT films. Further, to make comparisons and discussions. According to the experimental results by the heterodyne interferometer, the principal axis of a quarter-wave plate is rotated 0 to 180°in increments of 5°(22.5°is included), the correlation coefficient is determined to be 0.99997 and the average relative error of the principal axis is 0.66%. When the principal axis is orientated at 22.5 ° , the average relative error of the retardance for ten times measurements is 0.47%. These results validate the measurement system methodology. The applied voltage on the PLZT films is from 0 to 0.5V in increments of 0.1V. The average retardance of PLZT film is determined as 15.20°. Further, the average of retardance of PLZT films of a PT or PLT layer is determined as 15.34° and 16.88°, respectively. From 400nm to 700nm, the transmittance of PLZT film without a seeding layer isdetermined as 72.36%. Further, the transmittances of PLZT films with a seeding layer as PT or PLT are determined as 63.47% and 71.27%, respectively. As above, the reference ITO is annealed at 500℃. The thickness of PT or PLT is 24nm, respectively, and that of PLZT film is 500nm by the SEM measurement. From the comparison, the retardance of PLZT films with a seeding layer is greater than that of the PLZT films without a seeding layer.The transmittance of PLZT films with a PLT seeding layer is higher than that of PLZT films with a PT seeding layer. Finally, we could know the seeding layer plays a key in the increase of the retardance and avoid optical loss, may due to the increase of crystalline resulted from the addition of a seeding layer into the PLZT film.