Single walled carbon nanotube/Si heterojunctions for high responsivity photodetectors

• Published in: Nanotechnology Vol. 28; no. 43; p. 435201
• Main Authors: Salvato, M, Scagliotti, M, De Crescenzi, M, Crivellari, M, Prosposito, P, Cacciotti, I, Castrucci, P
• Format: Journal Article
• Language: English
• Published: England IOP Publishing 27.10.2017
• Subjects: carbon nanotubes; optical transmittance; photodetector; potential barrier
• ISSN: 0957-4484; 1361-6528
• DOI: 10.1088/1361-6528/aa8797

Single walled carbon nanotube/n-Si (SWCNT/n-Si) hetero-junctions have been obtained by depositing SWCNT ultra-thin films on the surface of an n-Si substrate by dry transfer method. The as obtained junctions are photo sensitive in the measured wavelength range (300-1000 nm) and show zero bias responsivity and detectivity values of the order of 1 A W−1 and 1014 Jones respectively, which are higher than those previously observed in carbon based devices. Moreover, under on-off light excitation, the junctions show response speed as fast as 1 s or better and noise equivalent powers comparable to commercial Si photomultipliers. Current-voltage measurements in dark and under illumination suggest that the devices consist of Schottky and semiconductor/semiconductor junctions both contributing to the fast and high responses observed.