Modeling of electrically tunable metamaterial embedded intersubband transitions in GaN HEMT for terahertz applications

This paper presents the computational study of the combined metamaterial driven inter-sub band transition phenomenon in GaN HEMT which is possible mode to extend its operating frequency well beyond its present cutoff frequency to THz band. It has been reported that the device dimension and geometry act as terahertz (THz) metamaterial and its couple with two-dimensional electron gas (2DEG) inside triangular quantum well of HEMT. Semiconductor device modeling has been used to extract intersubband (ISB) resonance phenomena by solving Schrodinger- Poisson equations self-consistently and k.p method. Terahertz response of entire GaN HEMT device has been modeled using Finite difference frequency domain electromagnetic simulation for 0.3 to 3.0 THz region. The combination of external electrical field dependent tunable ISBT and metamaterial driven enhancement of electric field distribution inside channel due to THz illumination clearly explain the GaN HEMT device behavior at THz frequency