Bow-tie antenna-coupled graphene FETs for direct detection at 0.6THz

Abstract

The recent demonstration of the electric field effect in graphene, a two-dimensional carbon lattice, and the measurement of its extraordinary room-temperature properties have sparked enormous interest in graphene as a material in electronics. Atomically thin and conductive, graphene has many options for integration with existing electronic devices and opportunities for the development of new devices. Graphene has a high carrier mobility and high carrier saturation velocity at room temperature, two properties which give it the potential for use in high-speed, high-frequency applications. Technologies operating at terahertz (1 1012 Hz) frequencies are becoming more numerous as an effort is made to close the so-called terahertz gap, and graphene has recently emerged as a viable terahertz material. This thesis presents terahertz (THz) direct detectors based on antenna-coupled graphene eld effect transistors (GFETs). These GFETs were fabricated using both mechanically exfoliated graphene and graphene grown by chemical vapor deposition (CVD) and integrated with split bow-tie antennae. These direct detectors are capable of room-temperature rectification of a 0.6 THz signal and achieve maximum optical responsivities of 13.0 V/W and 9.1V/W and minimum noise equivalent power (NEP) of 530 pW/Hz0:5 and 490 pW/Hz0:5 for the CVD and exfoliated detectors, respectively. These results are a significant improvement over previous work done with graphene direct detectors and are comparable to other established direct detector technologies. This is the first time room temperature direct detection has been demonstrated using CVD graphene, and because large-area graphene can be produced by CVD growth, scalable graphene detector production is now a possibility.