Al/maleic anhydride (MA)/p-Si metal-polymer-semiconductor (MPS) diodes have been prepared by spin coating of an organic film on p-Si substrate. These MPS structures have a good rectifying behavior. The diode parameters from the forward I-V characteristics such as the ideality factor (n), barrier height (BH) and series resistance have been analyzed by well-known methods. These methods are standard I-V characteristics, Cheung, Norde, Lien-So-Nicolet and Werner methods. The ideality factor, series resistance and barrier height values obtained from these methods have been compared and discussed in accordance with each other. Barrier height (BH) and series resistance are responsible from non-ideal behavior of I-V characteristics. (C) 2014 Elsevier B.V. All rights reserved.