High-power three-dimensional polymer FETs

We report high-power three-dimensional organic field-effect transistors (3D-OFETs) with a newly developed polymer semiconductor of poly(2,7-bis(3-icosylthiophene-2-yl)naphtha[1,2-b:5,6-b′]dithiophene) (PNDTBT-20).The active layer is formed on approximately 1 μm-high vertical walls in the 3D structure. The walls are densely arranged so that each channel requires very small area in the substrate, which results in extremely high-output-current per unit area. Large current density exceeding 5 A/cm² was achieved. Surface wettability of the 3D structure is modified with phenylaminosilanes to reproduce the performance in many devices so that the polymer neatly covers the sidewalls. Such high current density and improved reproducibility can be beneficial for practical applications as current-driven displays using organic light-emitting diodes, for example.

► We developed a three-dimensional structure for high-power organic field-effect transistors.
► A new polymer semiconductor material is used for the active channels in 3D-OFETs.
► Phenylaminosilane is used to modify surface wettability of the 3D structure.
► Large output current density over 5 A/cm2 is achieved.