| Summary: | 碩士 === 國立中山大學 === 電機工程學系研究所 === 88 === The Mg-modified lead titanate [(Pb1-xMgx)TiO3,abbreviated to PMT] thin films were deposited on Pt/SiO2/Si substrates by spin coating with sol-gel processing in this thesis. 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 Mg content (0~10 mol%) and the heating temperature (500~800℃), the effects of various processing parameters on the thin films growth are studied. The effects of various Mg contents on the response of pyroelectric IR detector devices are studied also.
Experimental results reveal that the Mg contents will influence strongly on grain size, dielectricity, ferroelectricity and pyroelectricity of PMT thin films. With the increase of Mg content, the grain size of PMT thin film decrease slightly, and the lattice structure of PMT thin film will change from tetragonal to cubic when the Mg content over 8 mole%. The relative dielectric constant of PMT thin film increases from 25 up to 91. The tan�� increases from 0.0008 to 0.0021, Ec decreased from 80 KV/cm to 25 KV/cm, and Pr decreases from 8.7 �媴/cm2 to 2.3 �媴/cm2, but �� increases from 2�e10-8 C/cm2K up to 3.86�e10-8 C/cm2K with an increase of Mg content. In addition, the results also show that the PMT thin film possesses the largest figures of merit Fv (1.46×10-10 Ccm/J) and Fm (2.5×10-8 Ccm/J) at the heating temperature of 700℃ and Mg content of 6 mol％. The voltage responsivities (Rv) measured at 20 Hz increase from 1463 to 5280 V/W and the specific detecivities (D*) measured at 100 Hz increase from 2.44×107 to 5.12×107 cmHz1/2/W with an increase of Mg content from 0 to 6 mol%. However, the voltage responsivity and the specific detecivity decrease with Mg content in excess of 6 mol%. The results show that PMT(6) pyroelectric thin film detector exists both the maximums of voltage responsivity and specific detecivity. Therefore, PMT(6) thin film exhibits the best IR characteristics for detector material.
|
|---|
