The propagation of shock waves with THz frequency in field-effect transistors

The investigation on propagation of shock waves with terahertz frequency in field-effect transistors has promoted the development of terahertz radiators and detectors. In this paper, we analyze the nonlinear behavior of shock waves with THz frequency in field-effect transistors and study their propagation characteristics at different viscosity coefficients and times. Using reductive perturbation expansion, the hydrodynamic equations are reduced to a Burgers equation governing the characteristic of shock structures in field-effect transistors. We investigate the evolution of shock waves with different viscosity coefficients and times numerically. The analytical and numerical results show that there are monotone shock waves and oscillatory shock waves in this system and an increase in the viscosity coefficient will lead to the diminishment of oscillation. These properties could make the field-effect transistors advantageous for realization of practical terahertz radiation and detection.