Organic Semiconductor and Plasmonic Gold Nanoparticle Based Transistor

Organic semiconductor-based devices such as field effect transistors (OFET) show promise in electronics and photodetection due to low-temperature and solution processability as well as the ability to be fabricated on flexible substrates such as polymer films. However, charge carrier mobilities are low relative to inorganics, ranging from 0.001-1 cm²/Vs compared to 100-500 cm²/Vs in silicon devices. The incorporation of metal nanoparticles into the active layer of an OFET device offers enhanced optical properties such as an increased absorption cross-section which we predict leads to enhanced sensitivity in a photodetector due to the excitation of the surface plasmon resonance of the gold nanoparticle. In the absence of illumination, we predict the gold nanoparticles will act as traps leading to suppression of dark current. 6,13-Bis(triisopropylsilylethynyl) (TIPS)-pentacene OFETs are fabricated on a heavily-doped silicon wafer with an SiO₂ gate dielectric layer and gold electrodes. The TIPS-pentacene active layer is drop cast from solution to create a bottom-gate bottom-contact geometry. Results will be presented to elucidate the effect of gold nanoparticles in the active layer on charge carrier mobility and on/off ratio.