Fabrication and characterization of suspended La_0.7Sr_0.3MnO₃ nanofibers for high-sensitive and fast-responsive infrared bolometer

Abstract

La1−x Sr x MnO3 manganite oxides have shown great potential for infrared (IR) sensing. In this study, La0.7Sr0.3MnO3 (LSMO) nanofibers, synthesized by a simple electrospinning process, are suspended between gold interdigitated electrode (IDE). These electrodes, which acts as a supporting platform for the dangling nanofiber, are microelectromechanical systems based that can be fabricated quickly and economically with fewer fabrication steps. Due to the large surface-area-to-volume ratio, these fibers have outstanding thermo-electrical properties, which puts them in the leagues of materials suitable for IR sensing. Performance-wise these hanging nanofibers belong to a class of promising thermal sensors due to negligible thermal loss. The optoelectrical characterization shows its temperature coefficient of resistance (TCR) is −1.48%K−1, and its electrical resistance follows an inverse square law for distance from the IR source. The fabricated LSMO nanofibers based microbolometer has a significantly low thermal time constant with average thermal response and recovery time of 63 ms and 77 ms, respectively. Furthermore, they show encouraging bolometric properties with thermal conductance, thermal capacitance, voltage responsivity, and thermal noise limited detectivity of 3.6 × 10−3WK−1, 0.2268 × 10−3JK−1 , 1.96 × 105VW−1, and 3.7 × 108cm Hz1/2W−1 respectively. The high voltage responsivity and TCR, commensurate with the ultralow response and recovery time confirm that the fabricated Microbolometer can find industrial applications as thermal sensors.