Bio Organic-Based Gate Dielectric Materials for Thin Film Transistors

The potential of bio-dielectrics for thin film transistor applications was explored via the incorporation of titanium dioxide (TiO 2 ) nanoparticles, rutile form, a high dielectric constant (ɛ) ceramic, in the deoxyribonucleic acid (DNA) bio-polymer. The DNA-ceramic hybrid films were fabricated from stable suspensions of the TiO 2 nanoparticles in viscous, aqueous DNA solutions. Dielectric characterization revealed that the incorporation of TiO 2 in DNA resulted in enhanced dielectric constant (14.3 at 1 kHz for 40 wt % TiO 2 ) relative to that of DNA in the entire frequency range of 1 kHz-1 MHz. Variable temperature dielectric measurements, in the 20-80 ° C range, of the DNA-TiO 2 films revealed that the ceramic additive stabilizes DNA against large temperature dependent variations in both ɛ and the dielectric loss factor tan δ. The bulk resistivity of the DNA-TiO 2 hybrid films was measured to be two to three orders of magnitude higher than that of the control DNA films, indicating their potential for utilization as insulating dielectrics in transistor and capacitor applications.