Numerical Simulation on the Voltage Response of Field Effect Transistor by Focused Terahertz Radiation

A numerical method is proposed to simulate the corresponding terahertz photoresponse which is induced by radiations between source-and-gate and gate-and-drain electrodes in field effect transistors. Simulations illustrate that the response of terahertz radiation in field effect transistor depends on the gate bias. The response contains contributions of different polarities which induced by radiations between `source and gate electrodes´ and `gate and drain electrodes´ respectively. The simulation matches well with the existing theory quantitatively. The proposed method is also used to study the response in resonant region by changing some parameters of field effect transistors (FET). The results illustrate that it is a useful tool in THz detector design and optimization.