Investigation of structural and electrical properties of Al2O3/PVP nano hybrid composite (as OFET dielectric gate)

Al2O3/PVP nano-hybrid composite samples are synthesized using sol-gel method at 75°C. Weight percent of poly 4-vinyl phenol and aluminum oxide is 0.0, 0.28, 0.56, and 0.84. To study the nano-structural and electrical characteristics, X-ray diffraction, Fourier transfer infrared radiation, scanning electron microscopy, and atomic force microscopy are used. Dielectric constant of the samples is measured using “GPS 132 A” multi-meter. The results show that the highest amounts of dielectric constant at the frequency of 120 and 1 kHz are related to Al2O3 + 0.28 %wt. PVP(k=35) and Al2O3 + 0.56 %wt. PVP (k=26) nano-composite samples, respectively. Therefore, at the frequency of 120kHz, Al2O3 + 0.28 %wt. PVP nano-composite sample, due to having higher equivalent oxide thickness, less roughness, ohmicproperties, smaller size of nano-crystallites (Scherrer diameter of 45nm), higher dielectric constant, and as a result of less leakage current, is recommended as the gate dielectric for the future of organic field effect transistors.