Ultrafast graphene photodetector.
Graphene research so far has focused on electronic rather than photonic applications, in spite of its impressive optical properties. These include its ability to absorb approximately 2% of incident light over a broad wavelength range despite being just one atom thick. Here, we demonstrate ultrafast transistor-based photodetectors made from single- and few-layer graphene. The photoresponse does not degrade for optical intensity modulations up to 40 GHz, and further analysis suggests that the intrinsic bandwidth may exceed 500 GHz. The generation and transport of photocarriers in graphene differ fundamentally from those in photodetectors made from conventional semiconductors as a result of the unique photonic and electronic properties of the graphene. This leads to a remarkably high bandwidth, zero source-drain bias and dark current operation, and good internal quantum efficiency.
Xia
Fengnian
F
IBM Thomas J Watson Research Centre, Yorktown Heights, NY 10598, USA. fxia@us.ibm.com
Mueller
Thomas
T
Lin
Yu-Ming
YM
Valdes-Garcia
Alberto
A
Avouris
Phaedon
P