In the present work, the surface morphology, structural and optical features of graphene oxide (GO) films are investigated. The Al/GO/n-InP MIS diode is formed by depositing GO layer on n-InP wafer for the barrier enhancement. Interfacial properties of the MIS diode with GO interlayer are extracted from current-voltage (I-V) measurement. The simple diode parameters such as barrier height and ideality factor are extracted from I-V plots, and the values are compared with those of conventional Al/n-InP MS contact. The value of barrier height (BH) for the Al/GO/n-InP contact is found as 0.85eV. The BH value of 0.85eV of the Al/GO/n-InP MIS structure is as high as around 100% compared to the value of 0.43eV of the Al/n-InP reference contacts. We have showed that the value of 0.85eV is one of the highest values presented for reference contacts with an interlayer.