A Multilayer-Graphene/Silicon Infrared Schottky Photo-Diode

Lateral effect, Schottky photo-diodes are commonly used as magnetic- and position sensing- detectors. Yet, they can only respond to ultraviolet- and visible-light because of the low optical transmittance in metals at long wavelengths, such as infrared light. Furthermore, Schottky contacts to narrow-band gap semiconductors are challenging to fabricate. Here, it is shown that an extended multilayer-graphene/silicon junction can be used as a lateral photo-diode in the infrared range. A multilayer graphene film was grown on an intrinsic-silicon substrate. The film shows graphene order near the interface to become amorphous carbon as the film grows in thickness. Since amorphous carbon behaves as a metal, this results in an effective metallic/2D/Si heterostructure, showing a rectifying behavior in the measured current-voltage characteristics. Moreover, photo-induced Hall effect measurements show that the proximity to graphene increases the spectrum of absorbance of silicon. This work shows that 2D materials can be used to extend the range of application of silicon to the infrared wavelengths.