ABSTRACT
We have demonstrated a solid carbon source such as camphor as a natural precursor to synthesize a large area mono/bi-layer graphene (MLG) sheet to fabricate a nanowire junction-based near infrared photodetectors (NIRPDs). In order to increase the surface-to-volume ratio, Si-nanowire arrays (SiNWAs) have been developed by the metal assisted chemical etching (MACE) process. The camphor-based MLG/Si and MLG/SiNWAs Schottky junction photodetectors have been fabricated to achieve an efficient response under self-driven condition in the near infrared (NIR) regime. Due to a balance between light absorption capability and surface recombination centers, devices having SiNWAs obtained by etching for 30 min shows a better photoresponse, sensitivity and detectivity. Fabricated NIRPDs can also be functioned as self-driven devices which are highly responsive and very stable at low optical power signals up to 2 V with a fast rise and decay time of 34/13 ms. A tremendous enhancement has been witnessed from 36 μAW−1 to 22 mAW−1 in the responsivity at 0 V for MLG/30 min SiNWAs as compared to planar MLG/Si PDs, indicating an important development of self-driven NIRPDs based on camphor-based MLG for future optoelectronic devices.
