Photovoltaic Performance of a Rotationally Faulted Multilayer Graphene/n-Si Schottky Junction

Abstract

We report the fabrication and photovoltaic performance of a rotationally faulted multilayer graphene (rf-MLG)/n-Si Schottky junction device. A thickness-controlled rf-MLG is synthesized using a 5 {\mu}m Ni foil catalyst via the chemical vapor deposition method and transferred to the n-Si substrate via a polymer-free process, enabling facile and cost-effective fabrication. The device demonstrates an ideality factor of 1.67, a rectification factor of approximately 4x10^5 at {\pm}1.0 V, and a Schottky barrier height of 0.83 eV. A strong linear relationship between light intensity and photocurrent is also observed. Furthermore, the device exhibits a peak external quantum efficiency of ~26% at 540 nm and a peak internal quantum efficiency of ~97% at 410 nm. Transient photocurrent and photovoltaic measurements show approximately one-microsecond extraction and several-millisecond recombination times, respectively, revealing effective charge collection for photovoltaic applications. These results indicate that the rf-MLG/n-Si Schottky junction is well-formed and achieves performance comparable to that of SLG devices, demonstrating its potential for optoelectronic applications.