Effect of Mobility Degradation on the Device Performance of Organic thin-film transistor's

The quest for alternative materials to Silicon has lead the technological industry to introduce a new class of materials i.e. 'organics'. The semiconducting properties of organic materials has made possible the realization of organic thin-film transistor (OTFT) which provides a major area of research in the device design technology. It is a well-known fact that OTFT's exhibit the Poole-Frenkel mobility mechanism wherein the material mobility increases with the increase in gate voltage. In this paper, an attempt is made to investigate the mobility behaviour of pentacene (intrinsic) based OTFT in bottom-contact configuration. The device characteristics are studied based on two-dimensional numerical simulation and analysis. Due to the grain structure of pentacene and interface charges, the material mobility degrades due to surface roughness and scattering phenomenon. These mobility degradation effects have been incorporated into the numerical analysis and it has been found that the device characteristics show a significant deviation from the linear trend at high gate voltages. The influence of mobility degradation on device performance parameter metrics i.e. V-TH, G(M) and ION/IOFF has been studied and it has been found that there is substantial change in these parameters.