This thesis deals with the study of charge transport through organic semiconductors incorporated in Organic Field-Effect Transistors (OFETs). Great attention is given to the interfaces in the OFETs and the properties of which were tuned to modulate transistor response. The stability of the device under switching states and the mechanism governing charge injection were studied systematically. In a fundamental level the charge transport through self-assembled monolayers comprising of variety of π-conjugated molecules were investigated. In this thesis the charge transport process and different parameters affecting this phenomenon are investigated in detail by fabrication and characterization of three terminal devices based on OFET architectures and two terminal devices consisting junctions incorporating mono-molecular layer on surface of metal electrode. Among the different aspects governing the charge injection in macroscopic organic thin film transistors particular emphasis was given to the interface engineering by tuning the (i) Dielectric/semiconductor interface, and (ii) Metal electrode/semiconductor. To explore aspects governing charge transport within the channel of the device we investigated the property of (iii) semiconductor intrinsic mobility and (iv) usage of blends in the active layer of the transistor. On the nanoscale the charge transport through a mono molecular layer chemisorbed onto metal electrodes was investigated. To perform electrical characterization on self-assembled monolayer (SAM) a custom in-house setup comprising of eutectic alloy of liquid metallic gallium indium (GaInE) probe electrode was built.
