The Study of Pyroelectric Detectors Based on PbTiO3

• Main Authors: Chih-Ming Wang, 王志明
• Other Authors: Ying-Chung Chen
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/30319068901859751134

博士 === 國立中山大學 === 電機工程學系研究所 === 88 === The pyroelectric ceramic thin films and detectors based on PbTiO3 that exhibits a low dielectric constant and a high pyroelectric coefficient were fabricated by a sol-gel method in this thesis. The lanthanum (La) and calcium (Ca) were adopted as dopants. The PLT and PCT thin films were deposited on Pt/SiO2/Si substrates by spin coating. 1,3 propanediol was used as solvent to minimize the number of cycles of spin coating and drying processes to obtain the desired thickness of thin film. By changing the dopant content and the heating temperature, the effects of various processing parameters on the thin films growth are studied. The effects of various dopant contents on the response of pyroelectric detectors are also discussed. Experimental results reveal that the dopant contents will influence strongly on the characteristics of thin films such as microstructure, dielectricity, ferroelectricity and pyroelectricity. With the increase of dopant content, the grain size, the coercive field (Ec) and the remanent polarization (Pr) of thin films decrease. The relative dielectric constant (εr) and the pyroelectric coefficient (g) of thin films increase with increasing the dopant content. In addition, the results also show that the PLT(10) and the PCT(25) thin films exhibit large figures of merit Fv for voltage responsivity (Rv) and Fm for specific detectivity (D*) at the heating temperature of 700℃. In the pyroelectric properties of thin film detectors, Rv and D* increased with an increase of dopant content. However, Rv and D* decreased when La and Ca content exceeded 10 mol% and 25 mol%, respectively. The PLT(10) and the PCT(25) pyroelectric thin film detectors exist both the maximums of Rv and D*. The results are consistent with the evaluations of Fv and Fm of thin films.