Intense-pulsed-UV-converted perhydropolysilazane gate dielectrics for organic field-effect transistors and logic gates

Abstract

We fabricated a high-quality perhydropolysilazane (PHPS)-derived SiO₂ film by intense pulsed UV irradiation and applied it as a gate dielectric layer in high-performance organic field-effect transistors (OFETs) and complementary inverters. The conversion process of PHPS to SiO₂ was optimized by varying the number of intense pulses and applied voltage. The chemical structure and gate dielectric properties of the PHPS-derived SiO₂ films were systematically investigated via Fourier transform infrared spectroscopy and leakage current measurements, respectively. The resulting PHPS-derived SiO₂ gate dielectric layer showed a dielectric constant of 3.8 at 1 MHz and a leakage current density of 9.7 × 10⁻¹² A cm⁻² at 4.0 MV cm⁻¹. The PHPS-derived SiO₂ film was utilized as a gate dielectric for fabricating benchmark p- and n-channel OFETs based on pentacene and N,N′-dioctyl-3,4,9,10-perylenedicarboximide (PTCDI-C₈), respectively. The resulting OFETs exhibited good electrical properties, such as carrier mobilities of 0.16 (±0.01) cm² V⁻¹ s⁻¹ (for the pentacene OFET) and 0.02 (±0.01) cm² V⁻¹ s⁻¹ (for the PTCDI-C₈ OFET) and an on–off current ratio larger than 10⁵. The fabrication of the PHPS-derived SiO₂ gate dielectric layer by a simple solution process and intense pulsed UV irradiation at room temperature serves as a novel approach for the realization of large-area flexible electronics in the flexible device industry of the future.