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 x 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-C-8), respectively. The resulting OFETs exhibited good electrical properties, such as carrier mobilities of 0.16 (+/- 0.01) cm(2) V-1 s(-1) (for the pentacene OFET) and 0.02 (+/- 0.01) cm(2) V-1 s(-1) (for the PTCDI-C-8 OFET) and an on-off current ratio larger than 10(5). 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.