Numerical Investigation of the Instability-Based Power Emission from an Ungated Plasmonic HEMT Using Complete Hydrodynamic Model

The full-wave analysis of the Dyakonov-Shur instability in an ungated short-channel high electron mobility transistor (HEMT) is investigated in this paper. This mechanism causes the emission of electromagnetic radiations by the device. The accurate analysis of the device is important especially when large electric fields are present. Herein, to analyze such structures, the complete hydrodynamic model, which is the simultaneous solution of Maxwell's equations and the first three moments of the Boltzmann transport equation, is used. This model well describes the electron-wave interactions by considering the transport parameter variations with the electron energy and temperature. These variations are especially considerable when the emitter operates at high electromagnetic fields and were not considered in previous studies. The obtained results demonstrate the oscillation current along the channel and consequently the radiated power of the device are severely influenced by the transport parameter variations. The developed analysis method describes the behavior of the device as a terahertz emitter more accurately than the available ones.