J. Phys. IV France 08 (1998) Pr9-139-Pr9-142
PT/P(VDF-TrFE) 0-3 nanocomposite thin film pyroelectric sensorsY. Chen1, J. Li1, H.L.W. Chan1, C.L. Choy1 and K.Y. Tong2
1 Department of Applied Physics and Materials Research Centre, The Hong Kong Polytechnic University, Hunghom, Kowloon, Hong Kong
2 Department of Electronic Engineering, The Hong Kong Polytechnic University, Hunghom, Kowloon, Hong Kong
The performances of four different pyroelectric single-element sensor configurations have been evaluated. The sensing element is either a composite of nanometer-size particles of lead titanate (PT) embedded in vinylidene-trifluoroethylene [P(VDF-TrFE)] copolymer or P(VDF-TrFE). Configuration I consists of the sensing element spin-coated on a silicon substrate. Configuration II, comprising the same sensing element but with the substrate etched away, has voltage (Rv) and current (Rl) sensitivities which, at an incident radiation modulation frequency of 10 - 100 Hz, are more than one order of magnitude higher than those of configuration I. High Rv and Rl can also be achieved by depositing a 13 µm thick polyimide (PI) thermal buffer layer between the sensing element and the silicon substrate (configuration III). Configuration IV, fabricated by etching away the substrate of configuration III, has similar Rv and Rl values as configuration II if the thickness of the PI layer is below 2.3 µm. Moreover, configuration IV is mechanically more robust than configuration II. For each configuration, the PT/P(VDF-TrFE) nanocomposite sensor has higher voltage and current sensitivities than the copolymer sensor.
© EDP Sciences 1998