KTa_(0.55)Nb_(0.45)O_3薄膜的介电和铁电及热释电性能研究

STUDY ON THE DIELECTRIC, FERROELECTRIC AND PYROELECTRIC PROPERTIES OF KTa_(0.55) Nb_(0.45) O_3 THIN FILMS

在ＢＴ／Ｐｔ／Ｔｉ／ＳｉＯ２／Ｓｉ 衬底上用溶胶－ 凝胶法制备了ＫＴａ０．５５Ｎｂ０．４５Ｏ３（ＫＴＮ） 薄膜．０ ．５ μｍ ＫＴＮ－ ０．０８ μｍ ＢＴ 薄膜在２５ ℃，１ ．０ ｋＨｚ 时，其εｒ＝ １ １１４，ｔａｎδ＝２ ．５ ％ ；１２ ℃时，其Ｐｒ＝ ２．１ μＣ／ｃｍ２ ，Ｐｓ＝４ ．２ μＣ／ｃｍ２， Ｅｃ＝ ５．８ ｋＶ／ｃｍ ．０ ．５ μｍ厚ＫＴＮ膜的Ｃｕｒｉｅ 温度为３５ ℃；２５ ℃，１ ．０ ｋＨｚ 时，ＫＴＮ 膜的εｒ＝ １ ４１２ ． 估算ＫＴＮ 材料的体积热容Ｃｖ ＝ ２ ．７３ Ｊ／ｃｍ３·Ｋ．ＫＴＮ 薄膜在室温及１０３ ｋＶ／ｃｍ 下极化３０ ｍｉｎ 后，其室温热释电系数ｐ ＝ ５ ．１ ×１０ －７ Ｃ／ｃｍ２·Ｋ，电压响应优值Ｆｖ ＝ １ ．３２ ×１０ －１０ Ｃ·ｃｍ／Ｊ，探测度优值Ｆｄ＝ ３．１５ ×１０ －１０ Ｃ·ｃｍ／Ｊ，该薄膜是一种优异的热释电材料．

KTa 0.55 Nb 0.45 O 3(KTN) thin films were prepared by sol-gel method on BT/Pt/Ti/SiO 2/Si substrates. KTN film with a thickness of 0.5 μm and BT film with a thickness of 0.08 μm show a relative permittivity of 1 114 at room temperature and dielectric loss of 0.025 at 1.0 kHz. The remanent polarization is 2.1 μC/cm 2, spontaneous polarization is 4.2 μC/cm 2,coercive field is 5.8 kV/cm at 12 ℃. The maximum relative permittivity of 0.5 μm_thick KTN was observed at 35 ℃. Its relative permittivity at room temperature is calculated to be 1 412, volume heat capacity is 2.73 J/cm 3·K, pyroelectric coefficient at room temperature is 5.1×10 -7 C/cm 2·K,optimal value of voltage response is 1.32×10 -10 C·cm/J, optimal value of detectivity is 3.15×10 -8 C·cm/J. The results show that KTa 0.55 Nb 0.45 O 3 thin film is a kind of excellent pyroelectric material.