I-V-characteristics of Schottky diodes based on graphene/n-Si heterostructures

The authors investigated the electrical properties of graphene/n-Si Schottky diode heterostructures obtained by mechanical exfoliation of graphite to thin-layer graphene in an aqueous solution of polyvinylpyrrolidone as a result of the dynamics of the dispersed graphite mixture under the action of a mechanical blender. The graphene/n-Si structures differed in terms of duration of applying graphene films on n-Si substrates: 5, 10 and 15 min. The temperature of the substrates did not exceed 250°C. The formation of graphene layers was confirmed by the study of Raman scattering spectra in the frequency range of 1000—3250 cm–1, which show G and 2D bands with the features characteristic of low-layer graphene. The dependence of the electrical properties of the investigated surface-barrier graphene/n-Si structures on the duration of sputtering of graphene films was established. It was found that the value of the contact potential difference φk was 1.35, 1.32 and 1.27 V and the series resistance at room temperature was 3.4•106, 3.4•103 and 3.7•103 Ω for structures with the duration of graphene layer deposition 5, 10 and 15 min, respectively. The formation of both forward and reverse currents was dominated by the tunneling of charge carriers through the potential barrier.