A thin poly(ethylmethacrylate) (PEMA) layer is deposited on n-InP as an interlayer for electronic modification of Au/n-InP Schottky structure. The electrical properties of Au/PEMA/n-InP Schottky diode have been investigated by currentevoltage (I-V) and capacitance-voltage (C-V) measurements at different annealing temperatures. Experimental results show that Au/PEMA/n-InP structure exhibit a good rectifying behavior. An effective barrier height as high as 0.83 eV (I-V) and 1.09 eV (C-V) is achieved for the Au/PEMA/n-InP Schottky structure after annealing at 150 degrees C compared to the as-deposited and annealed at 100 and 200 degrees C. Modified Norde's functions and Cheung method are also employed to calculate the barrier height, series resistance and ideality factors. Results show that the barrier height increases upon annealing at 150 degrees C and then slightly decreases after annealing at 200 degrees C. The PEMA layer increases the effective barrier height of the structure as this layer creates a physical barrier between the Au metal and the n-InP. Terman's method is used to determine the interface state density and it is found to be 5.141 x 10(12) and 4.660 x 10(12) cm(-2) eV(-1) for the as-deposited and 200 degrees C annealed Au/PEMA/n-InP Schottky diodes. Finally, it is observed that the Schottky diode parameters change with increasing annealing temperature. (C) 2013 Elsevier B.V. All rights reserved.