Nano polymer Films by Fast Dip Coating Method for Field Effect Transistor Applications

Nano Polyvinyl alcohol films are prepared by fast dip coating method. Cleaned glass plates are used as substrate to prepare the above said films. The thickness of the films are measured by capacitance method, weighing method and cross checked by electronic measuring instrument (Tesatronic-TTD 20). IR spectrum is used to identify the coated films. The coated films are identified by IR spectrum. No pits and pin holes are found on the surface. The XRD spectrum indicated the amorphous nature of the films studied. Aluminium/PVA/Aluminum sandwich structures are formed to study the dielectric and AC conduction behaviour. The capacitance and dielectric loss of the films are measured in the frequency range of 0.1 kHz to 100 kHz for various temperatures ranging from 290 K to 450 K. The observed increase of capacitance with the decrease of frequency in the lower frequency range can be assigned to charge carriers being blocked at the electrodes. The decrease of capacitance with increasing frequency is also attributed to the increasing inability of the dipoles to orient them selves in a rapidly varying electric field. The AC conductivity is found to vary according to the relation σac α ωn, where the value of n depends on temperature and frequency. The value of activation energy is found to be 0.0015 eV ∼0.007 eV for various temperatures confirms the amorphous nature of the film.