A new growth process for crystalline ultra-thin layers of conjugated oligomers used in field-effect transistor applications

Abstract

Most organic semiconductor materials dewet on silicon wafers with thermal oxide layers. While Siwafers represent convenient substrates for building a field effect transistor (FET), dewetting largely destroys the possibility for obtaining a compact and continuous crystalline thin organic semiconductor film and thus limits the mobility in these systems. Using oligothiophenes, we present an approach where the initial dewetting process can be turned into an advantage for generating very thin but large crystalline domains of a size up to the millimetres with all molecules sharing a single orientation. Our approach can be easily extended to other molecules, which have strongly differing growth velocities in the various directions of the crystal, for example due to directional π-stacking interactions. FETs devices based on such large crystalline domains showed charge carrier mobilities that were two orders of magnitude higher compared to non-crystallized films.

High-Performance Organic Field-Effect Transistors of Liquid Crystalline Organic Semiconductor by Laser Mapping Annealing

“…It is known that most organic semiconductor materials are prepared on silicon wafers with a thermally oxidized layer and that when the liquid film is thick enough, the film can be stabilized with gravity. If the thickness of the liquid film is too small, with the help of capillarity, the molecular force overwhelms gravity, and the liquid film is wetted [ 34 , 35 , 36 , 37 ]. Dewetting of the material largely destroys the compactness and continuity of the organic semiconductor film arrangement and, therefore, limits the mobility of the device.…”

Naphthyl Methylacrylate Block Copolymer Insulators for Application in Pentacene Organic Thin-Film Transistors

“…The manufacturing process of the most active layer is vacuum thermal evaporation deposition. , At lower substrate temperatures, some research results show that the diffusivity rate and mobility of pentacene molecules on the substrate are very low because the molecules do not have enough energy to find their thermodynamically stable positions; thus an amorphous film is formed. , Therefore, in order to obtain the ideal film consisting of ordered domains, the substrate temperature must be kept within a certain range.…”

2,1,3-Benzothiadiazole Small Donor Molecules: A DFT Study, Synthesis, and Optoelectronic Properties

“…Organic semiconductors are currently used in many fields of science, e.g., organic light-emitting diode (OLED), solar cells, transistors, molecular imaging, and sensors [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ]. Due to their conductive and optical properties, the possibility of easy modification, flexibility, and low production costs, they displace their inorganic counterparts.…”