Photogenerated Currents in Pentacene Field Effect Transistors

This paper reports on organic FET transistors (OFETs) fabricated on silicon substrates using pentacene as active organic layer and gold as source and drain contacts. Photogenerated currents by a 625nm wavelength laser are experimentally observed. The observed light-induced increase of OFFT drain current by three-to-six orders of magnitude, depending on device operation and geometry suggests their potential for future light sensing applications. Bipolar conduction and electron trapping in pentacene films exposed to light are found responsible for some of the abnormal observed behaviors during experiments