Sol-Gel Derived Pyroelectric Barium Strontium Titanate Thin films for Infrared Detector Applications

摘要

Ba_(0.8)Sr_(0.2)TiO_3 thin films that are suitable for infrared detector applications have been prepared with a sol-gel process using a highly diluted precursor solution Columnar structure with grain size close to 200 nm was obtained with layer-by- layer homoepitaxy due to a very small thickness of individual layer. The measured pyroelecrtic coefficient is larger than 3.1Xl0~(-4) C/m~2K at the temperatures ranging from 10 to 26°C and reaches the maximum value of 4.1X10~(-4) C/m~2K at 16.8°C. The infrared detectivity of 4.6Xl0~7 cmHz~(1/2) W~(-1) has been obtained at 19°C and 10 Hz in the Ba_(0.8)Sr_(0.2)TiO_3 films deposited on thick (500 m) platinum coated silicon substrates. The better infrared response can be expected by the improvement in the thermal isolation of pyroelectric element and the electrode materials.