Polarization Induced Deformation Sensing in Thin Film Transistor

Abstract

Recently, as rapidly growing research interest in shape deformable electronics including display technical demands for shape deformation sensing devices are also increased. Including various sensing methods using resistivity, capacitance, and also optical system deformation sensing systems integrated with display systems is highly desired. Obviously, active deformation sensing using a thin film transistor (TFT) is most desirable due to the good compatibility with a pixelated array but this is still in challengable. Shortly, converting mechanical deformation energy into the electrical signal and further integrated signal in TFT is ideally desired. Electroactive material based on polarized materials such as ferroelectric polymers or dielectric elastomers can convert energies between mechanical deformation stress and electrical polarization change which results in charge volume density and also current change [1]. In particular, the resulting charge density amount is reversibly switchable by the polarization rotation induced by mechanical deformation. This is caused by a change in the direction of molecular arrangement due to the influence of external stress, resulting in a change in the direction of the dipole moment [2,3]. Using these polarization switching material properties, various sensor devices can be implemented.In this work, we investigated a feasibility study of strain deformation sensing in the TFT device structure by exploiting the polarization rotation switching of electroactive materials. As result, we could found a good reversible current changing selectivity from ID of field-effect transistor sensor which has an embedded rotational polarity change of polarization layer (Fig 1). We will report details of shape deformation stress sensing mechanism in TFT structure from the investigation of modified depletion property by strain-induced polarization change.