The characterization and fabrication of pyroelectric infrared sensors and application of gas monitoring

In the paper the pyroelectric infrared sensor with the lead zirconate titanate (PZT) (PbZr_0.3Ti_0.7O₃) thin film has been successfully fabricated. Prepared by a sol-gel process, the PZT thin film, which is chosen as infrared sensing film, uses lead acetate trihydrate, zirconium acetylacetone, acetylacetone, and titanium isopropoxide as starting materials. The fabrication process of device is discussed in detail. A new Au Pt-PZT-Pt infrared detecting structure on silicon substrate with a micro bridge is designed. Under the response and reference dual-element configuration, undesirable signals, caused by vibration, ambient temperature change and sunlight, are cancelled out at the input of the preamplifier circuit. The dual-element Structural design of device is discussed and analyzed in detail. In experiment, in order to use this infrared sensor to monitor gas concentration, we designed a detection device in the light of certain gas absorbs infrared radiation at specific (and often unique) wavelengths. Therefore, the narrow band filters are selected, 3.3plusmn0.03 um for methane characteristic absorption peak, and 3.9plusmn0.03 um for reference characteristic absorption peak, two filters are separating installed before in response and reference element of detector. The gas concentration is obtained by designing weak signal detect circuit and data arithmetic. First measurement for methane is reported. Experimental result shows the ability of methane detecting of the system based on the IR sensor.