We calculate the tunneling conductance of a graphene normal metal-insulator-superconductor (NIS) junction with a barrier of thickness $d$ and with an arbitrary voltage $V_0$ applied across the barrier region. We demonstrate that the tunneling conductance of such a NIS junction is an oscillatory function of both $d$ and $V_0$. We also show that the periodicity and amplitude of such oscillations deviate from their universal values in the thin barrier limit as obtained in earlier work [Phys. Rev. Lett. {bf 97}, 217001 (2006)] and become a function of the applied voltage $V_0$. Our results reproduces the earlier results on tunneling conductance of such junctions in the thin [Phys. Rev. Lett. {bf 97}, 217001 (2006)] and zero [Phys. Rev. Lett. {bf 97}, 067007 (2006)] barrier limits as special limiting cases. We discuss experimental relevance of our results.
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