Plasmon thin film transistor has great potential to be applied in present-day technologies including modern medical diagnostics. Here, we report the fabrication of plasmon thin film transistor, realized by depositing a nanocomposite material on a pre-fabricated transistor substrate. Plasma polymerized aniline rubrene hybrid semiconductor and gold nanoparticles are synthesized in a combined plasma process to form the nanocomposite material. Absorption spectra indicate that the polymer shows broad absorption in the UV-Visible region and inclusion of Gold nanoparticles (Au NPs) results in strongly enhanced absorption in the visible region of the electromagnetic spectrum due to plasmon resonance. The prepared thin film transistor device shows substantial increment of drain current when irradiated by a light source 520 nm, leading to significantly high responsivity and detectivity. The plasmon thin film transistor with enhanced photoresponse in the visible region can be a promising device for application in future technologies such as in the field of imaging, plasmonic integrated circuits, Human Machine Interfaces. It can also be used for varied medical applications e.g. biosensors and biomedical devices for personalized use.