The structural, chemical, electrical and carrier transport properties of high-k ZrO2 on n-type In P with Au electrode have been studied by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), current-voltage (I-V) and capacitance-voltage (C-V) techniques at room temperature. Results show that the high barrier height is achieved for the Au/ZrO2/n-InP metal-insulator-semiconductor (MIS) diode as compared to the Au/n-InP metal-semiconductor (MS) diode. Using Cheung's functions, the barrier height, ideality factor and series resistance are estimated for the MS and MIS diodes. The barrier heights are determined by I-V, Cheung's and surface potential-forward voltage plot for both the MS and MIS diodes which are found to be in good agreement with each other. Results indicate that the interface state density of Au/ZrO2/n-InP MIS diode is lower than that of Au/n-InP MS diode. This may be attributed to the fact that the introduction of the high-k ZrO2 interlayer led to reduction of the interface state density in the Au/n-InPMSdiode. Results indicate that the Poole-Frenkel emission is the dominant conduction mechanism in the lower bias region while Schottky emission is dominant in the higher bias region for both the Au/n-InP MS and Au/ZrO2/n-InP MIS diodes. (C) 2016 Elsevier B.V. All rights reserved.