Effect of pentacene thickness on organic thin film transistors: Role of pentacene/insulator interface

A top contact organic (pentacene) thin film transistor (OTFT) is exhibiting a variation in extracted field effect mobility as thickness of pentacene changes from 10 to 35 nm. Device simulation of an ideal OTFT does not exhibit any dependence on semiconductor thickness, as expected. In simulations, we systematically introduced effects based on low-mobility-layer adjacent to the dielectric, and energy level shift in the same layer as compared to the bulk pentacene, which then explains the experimental observations.