Low-Voltage n- and p-Channel Organic Transistors using Al2O3 Dielectric

The integration of high-k dielectric materials presents a promising strategy to reduce the operating voltage of organic thin-film transistors (OTFTs) while enhancing their overall performance. In this study, we explore the impact of a 20 nm Al2O3 interlayer deposited atop conventional SiO2 dielectrics on the electrical characteristics of both p-channel pentacene and n-channel N,N′-dioctyl-3,4,9,10-perylenedicarboximide (PTCDI-C8) OTFTs. Devices incorporating the Al2O3/SiO2 bilayer dielectric demonstrate marked improvements in electrical properties for both n-type and p-type devices, including increased drain current, transconductance, and carrier mobility, along with higher on/off current ratios at reduced operating voltages compared to those using SiO2 alone. Furthermore, this bilayer architecture lowers threshold and turn-on voltages, decreases subthreshold swing, and mitigates interfacial trap states and contact resistance, thereby promoting more efficient charge injection and enhanced device operation across both charge carrier types. These findings highlight the effectiveness of Al2O3/SiO2 dielectric engineering as a viable approach for advancing low-power, high-performance organic electronics.