Active layer and electrode thickness dependent performances of bottom contact photosensitive organic field-effect transistors

Abstract Optimizing the thicknesses of the organic active layer and source/drain electrode layer of photosensitive organic field-effect transistors (PhOFET) for high device performance is of great importance. With the increase of organic active layer thicknesses, both the photocurrent and photoresponsivity display the same variation trend of increasing sharply at first and then tending to saturate at large values. The Au source/drain electrode-layer thickness shows great impact on the performance of PhOFET. With the increase of Au source/drain electrode-layer thicknesses, both the dark current and photoresponsivity increase sharply at first and then tend to saturate at large thicknesses. For pentacene PhOFETs with bottom-gate bottom-contact geometry, the Au source/drain electrode-layer thickness should be larger than 150 nm for optimized device performance. This research may supply a theoretical basis for the development of PhOFET.