Characterization of a Polymer-Based MEMS Pyroelectric Infrared Detector

AFRL/MLPJE had developed a novel thermal sensing material termed proteinimpregnated- polymer (PIP). Thus far, a proof-of-concept has been demonstrated using a macro-sized pixel (0.64 mm2) as a bolometric detector. In an effort to better characterize this novel thermal sensing material, experimental data was used to determine figures of merit (FOMs) comparative to off-the-shelf thermal detectors. Microelectromechanical (MEMS) pixels were designed and used as the support structure for an inkjet-deposited droplet of the PIP. During the material characterization, two observations were made: PIP is a pyroelectric material, and the polymer (polyvinyl alcohol (PVA)) without the protein was found to be more suited for measurements taken on the micro-scaled pixels. Both PVA and PVA doped with carbon black (PVA_CB) were the materials focused on in this research, with the latter being the material used for FOM characterization. Pyroelectric coefficients for PVA and PVA_CB were found to be 755.11 nC/(cm2 K), and 108.32 nC/(cm2 K), respectively, which are both two orders of magnitude higher than values for current pyroelectric polymers. A responsivity of 1.66 104 V/W, thermal time constant of 3.59 sec, noise equivalent power of 21.3 nW, and a detectivity of 1.93 105 cm Hz/W were the FOMs found in this thesis. Although the calculated FOMs are not stellar in comparison to current thermal detector technology, this material shows much promise. The shortfalls in FOMs could potentially be attributed to a poor pixel design. This thesis plants the scientific seed in cultivating a thermal imaging focal plane array (FPA) using a newly found pyroelectric polymer.