Electrical transport measurements and degradation of graphene/n-Si schottky junction diodes

Abstract

We report on the electrical properties, such as the ideality factors and Schottky barrier heights, that were obtained by using current density — voltage (J — V ) and capacitance — voltage (C — V ) characteristics. To fabricate circularly- and locally-contacted Au/Gr/n-Si Schottky diode, we deposited graphene through the chemical vapor deposition (CVD) growth technique, and we employed reactive ion etching to reduce the leakage current of the Schottky diodes. The average values of the barrier heights and the ideality factors from the J — V characteristics were determined to be ~0.79 ± 0.01 eV and ~1.80 ± 0.01, respectively. The Schottky barrier height and the doping concentration from the C — V measurements were ~0.85 eV and ~1.76 × 10¹⁵ cm ^-3, respectively. From the J — V characteristics, we obtained a relatively low reverse leakage current of ~2.56×10^-6 mA/cm^-2 at -2 V, which implies a well-defined rectifying behavior. Finally, we found that the Gr/n-Si Schottky diodes that were exposed to ambient conditions for 7 days exhibited a ~3.2-fold higher sheet resistance compared with the as-fabricated Gr/n-Si diodes, implying a considerable electrical degradation of the Gr/n-Si Schottky diodes.