Charge carrier mobility in pentacene is determined using three different methods, the standard one being the field effect transistor (FET), and the others, not much explored in organic materials are the impedance spectroscopy and the space charge limited current (SCLC). We have found that the FET technique yields exaggerated mobility values. We have obtained a mobility of 3.5 x 10(-2) cm(2)/V s for an applied electrical field of 3 x 10(7) V/m. We have characterized the growth and structural organization of pentacene layers using AFM and X-ray diffraction measurements to support our interpretation of the transport mechanisms. (c) 2012 Elsevier Ltd. All rights reserved.