| In this thesis we investigate electrostatic doping of a wide variety of novel materials incorporated in field-effect transistors (FETs), including polymers, organic molecular crystals, graphene and bilayer graphene. These studies have lead to substantial advances in our current understanding of these materials. Specifically, we performed the first infrared (IR) imaging of the accumulation layer in poly(3-hexylthiophene) (P3HT) FETs. Furthermore, we found that charge carriers in molecular orbital bands with light mass dominate the transport properties of single crystal rubrene. More recently, we explored the IR absorption of graphene and found several signatures of many-body interactions. Moreover, we discovered an asymmetric band structure in bilayer graphene and determined the band parameters with an accuracy never achieved before. Our work has demonstrated that IR spectroscopy is uniquely suited for probing the electronic excitations in nanometer-thick accumulation layers in FET devices. |
