Noise mechanisms investigation in pyroelectric infrared detectors based on Mn-doped Pb(Mg1/3Nb2/3)O3–0.27PbTiO3 vs. LiTaO3 single crystals

•High quality pyroelectric infrared detector based on PMNT and LT single crystals were fabricated.•Different mechanisms were found in the proposed detectors.•The dominated noise is tan δ noise for PMNT based detectors, while resistance noise for LT based ones at frequency of 10 Hz.•Three forms of figure of merit for detectivity were derived based on the different mechanisms.•Our investigation is significant in further evaluating and selecting better materials for pyroelectric infrared detectors.

Different noise mechanisms between Mn-doped Pb(Mg1/3Nb2/3)O3–0.27PbTiO3 (Mn-PMNT) and LiTaO3 (LT) based pyroelectric infrared detectors were observed under voltage mode, revealing that at low frequency of 10 Hz, dielectric loss noise dominates for Mn-PMNT based detectors, while resistance noise for LT based ones. Meanwhile, an extremely low equivalent voltage noise of appropriate 20 nV/Hz1/2 was obtained in Mn-PMNT based detectors, 1/4 times lower than that of the LT based detectors. On the basis of the different noise mechanisms, frequency dependence of figure of merit for detectivity (Fd) have been deduced, providing significant reference values for the analysis of different materials based pyroelectric detectors.