TSCuPc/Au hybrid trench devices. A comparative study of solution processed and thermally evaporated molecular channels

Organic semiconductors have potential applications in the spintronics field due to the weak spin scattering mechanism in organic molecules, which implies that the spin polarization of the carriers can be maintained for a much longer time (in the range µs to ms) than in inorganic materials. Cost-efficient, wafer level fabrication of such devices is one of the main challenges in this field. Currently e-beam lithography is used for fabricating the required small electrode gap dimensions. Previously, we reported an alternative approach for fabricating laterally stacked organic trench devices using conventional optical lithography, where paramagnetic (CoPc, CuPc) and diamagnetic Alq3 molecules were evaporated to form the organic channels. It was observed that the molecules form a membrane between the electrodes. In this work, solution processing of organic materials was tested by drop-coating of water-soluble 3,4',4",4‴-copper(II) phthalocyanine-tetrasulfonic acid tetrasodium salt (TSCuPc). Using this approach it was possible to fill the trenches. A comparative study of a solution processed device and a device with evaporated channel material is presented.