AbstractMeasured output characteristics of our prepared short‐channel organic transistor show the well known effect of a nonlinear increase of the drain current with positive curvature at low drain voltages. We investigated this peculiarity by means of 2D simulations considering the bilayer contact for source or drain, respectively. The simulations show that the low work function of the chromium adhesion layer causes the nonlinearity. Another important aspect demonstrated by the simulations is the estimation of the mobility applying the simple Shockley equation. The influence of the contact properties on the rise of the drain current results in erroneous values for the mobility as estimated directly from the current–voltage characteristics. Output characteristics of a 1 µm channel length transistor.magnified imageOutput characteristics of a 1 µm channel length transistor.(© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)