Study On The Infrared Absorption Characteristic Of Organic Materials

The sensing unit of infrared detector does not have good absorption characteristics and the ability of capturing infrared light directly affects the quality of detection devices. Special infrared absorption structure is needed to improve infrared absorptivity. Based both on the thermal mass of absorber structure and the infrared absorption coefficient, the research fulfills the design and fabrication of array micro-structure infrared absorption layer with organic material, and the test and analysis the infrared absorption characteristics are done.First, the principle of infrared absorber structure is researched in this paper. Based on the multiple reflection mechanism, infrared absorber structure with cubic array of organic material PDMS is designed. Second, by reactive ion etching micromachined of Si mask and PDMS embossing, the PDMS cubic array of various sizes structure are fabricated on the surface of ZnS. On mask etching, the deposition of aluminum film mask, wet etching of aluminum periodic patterns, reactive ion etching of manufacture are researched. Embossing process mainly include:seal press、solidify、demould. Finally, by testing and comparing the infrared absorption coefficients of different structures, the optimalized absorption structure are obtained, the relationship between the structure size and infrared absorption efficiency are analyzed.Experimental results:(1)Wet etching rate of aluminum thin-film periodic patterns;(2)RIE etching bosch process of different open sizes patterns;(3)PDMS array micro structure infrared absorber layer improves the absorption intensity of ZnS, average absorption strength of5μm to20μm can be raised from0.3to3.5;(4)The optimalizing absorption model is:cubic array structure with8μm side length,20μm height and8μm cell spacing, its relative absorption strength of5μm to12μm can reach4.0, and the transmittance will be the lowest20%.