Organic devices based on pentacene and perylene by the neutral cluster beam deposition method

In this study, on the basis of p-type pentacene and n-type N,N′-dioctyl-perylene-3,4,9,10-tetracarboxylic acid diimide (PTCDI-C8) organic field-effect transistors (OFETs) and two-input complementary NAND logic gates in the top-contact device configuration were produced and characterized. The organic active layers were deposited on hydroxyl-free polymethylmethacrylate (PMMA)-modified indium tin oxide (ITO) glass gate substrates by the neutral cluster beam deposition (NCBD) method. The morphological and structural properties of the organic semiconducting active layers on the PMMA substrates were examined using atomic force microscopy, X-ray diffraction and contact-angle goniometry. Based on the growth of high-quality, well-packed crystalline films on the PMMA dielectric-modified ITO gate substrates, the p- and n-type transistors exhibited hole and electron mobilities of 0.247 and 7.23 × 10⁻² cm²/Vs, respectively, in the air without encapsulation. The trap density and activation energy were also derived from the transport characteristics for the temperature dependence of the mobilities in the temperature range 20 − 300 K for the first time. Because of the well balanced p- and n-type OFETs in the devices, the complementary metal-oxide semiconductor (CMOS) NAND logic circuits exhibited a high voltage gain and a large noise margin with slight hysteresis.