Tailored electrical properties and conduction mechanism of plasma polymerized 2,6-diethylaniline and <i>N</i>,<i>N</i>,3,5-tetramethylaniline composite thin films

Plasma polymerized (PP) 2,6-diethylaniline (DEA) and N,N,3, 5 tetramethylaniline (TMA) composite thin films were deposited by dynamic plasma (AC, 50 Hz) polymerization technique using a capacitively coupled reactor of diverse monomer composition. The composite film thickness increased proportionally with the percentage of TMA in the composition. X-ray photoelectron spectroscopy confirmed the uniformity of the film composition, consisting primarily of carbon, nitrogen, and oxygen, with different possible groups such as C–C, C–H, C–N, and C–O. Field emission scanning electron microscopy images revealed smooth and homogeneous surface morphologies in the composite films, which contrast with the thin homopolymer films. The current density (J) vs voltage (V) behaviors of the homopolymer and composite polymer thin films sandwiched between aluminum electrodes demonstrated that the J values could be tailored by adjusting the individual monomer concentration in the PP(DEA:TMA) composite films, as well as by increasing the measurement temperature (298–373 K). The conduction behavior of these composite films exhibited ohmic characteristics in the lower voltage region (below 10 V), while space charge-limited conduction dominated in the higher voltage region (above 10 V) across the entire temperature region. The activation energy was ∼0.019 eV in the ohmic region and 0.260 eV in the non-ohmic region. Changing the composition of two monomers can tune the properties of the as-deposited films, making the film suitable for various electronic and optoelectronic devices.