Dynamic response of polycrystalline organic thin film transistors
In this dissertation, charge transport through organic field effect transistors is explored. In particular, small molecule-based devices consisting of Pentacene semiconducting thin films are investigated. The relationship between electric field and carrier velocity is explored over a wide range of electric fields. These velocities are then compared to directly measured velocities measured from transient measurements. New device structures are fabricated in order to provide low voltage operation, along with a method to stabilize the output response and reduce bias stress effects. A novel method is proposed to investigate the dynamics of trap response rate in highly localized systems through the characterization of the large signal frequency response of a vii device. This method is then used to gain greater insight into bias stress effects and the ability of a transistor to respond to a rapidly changing input. A greater understanding of the transport of charge through a channel is obtained, leading to a more realistic picture in which a single mobility value is an insufficient description of carrier transport through a material.