Grating-gate high electron mobility transistors for terahertz modulation

Abstract

Terahertz (THz) modulators are required for wireless communication, ultrafast THz interconnects and sensing applications. Great achievements in modulation are reported utilising GaN devices with two-dimensional electron gas (2DEG). In the current work, circular grating-gate transistors based on AlGaN/GaN heterostructures are designed and fabricated. Electrical characterisation of these devices reveals ohmic-like contacts for the source and drain, Schottky barrier for the gate structures and output transistor characteristics confirming the operation through a channel with 2DEG. These circular transistor structures can become a basis for the development of THz modulators where the plasmon polaritons of the grating metal structures will be coupled with the plasmon waves of the 2DEG allowing filtering and modulating THz waves