Tuning of Threshold Voltage in Organic thin film transistors using buried silver nanoparticles distributed floating gated contacts

Abstract

Digital logic circuits built with organic thin film transistors (OTFT) are often implemented using depletion-load logic employing unipolar devices with different threshold voltages. Distributed floating back-gated contacts are proposed using silver nanoparticles buried inside the semiconductor in order to alter the channel carrier concentration thereby causing the shift in threshold voltage. Simulation results are produced to show the effectiveness of the proposed method in tuning the threshold voltage. Mix-mode simulation of inverters show possibility of high gain and steep voltage transfer curve and small delay of 0.5 milliseconds. Experimental validation of threshold voltage tuning on p-channel OTFT was also achieved by depositing buried layer of silver nanoparticles during growth of semiconductor pentacene at the middle of its thickness. OTFT with buried silver nanoparticles had a negative shift in threshold voltage by 2 volts.