Numerical modeling of TeraHertz electronic devices

Abstract

We investigate by means of Monte Carlo simulations the physical processes associated with the emission of TeraHertz radiation in different electronic devices. We analyze four alternative and complementary strategies which seem to be promising candidates to obtain the TeraHertz emission: (1) a nitride maser based on the optical-phonon transit-time resonance, (2) the high-order harmonic generation in bulk materials and nanometric Schottky-barrier diodes, (3) the excitation of coherent plasma oscillations in micron and submicron diodes, (4) the current instabilities and plasma oscillations in high electron mobility transistors (HEMT). The numerical results show that several physical mechanisms can be exploited to increase significantly the operating frequency of these devices and the best conditions to optimize the radiation emission in the TeraHertz range are studied in detail.

A Planar Gunn Diode Operating Above 100 GHz

“…However, conventional vertical device architectures do not readily permit efficient fundamental-mode operation of vertical Gunn diodes much above 90 GHz in GaAs [5] or 315 GHz in InP [6]. However, recent numerical studies have shown that Gunn diodes are, in principle, capable of operation above 1 THz, provided that they are appropriately engineered [7]. The frequency of oscillation is determined by the time taken for a Gunn domain to form and complete a transit between the cathode and anode contacts.…”

Terahertz Emission from Collapsing Field Domains during Switching of a Gallium Arsenide Bipolar Transistor

“…Among various plasma instability scenarios [15] which may cause THz oscillations in electronic devices, the closest to our case appears to be the popular model of plasma waves in GaAs-based compounds [16], as confirmed experimentally in low-dimension field-effect transistors at cryogenic temperatures [17]. We would not attribute the results of our THz measurements to analogous plasma waves, however, as a number of very critical assumptions belonging to the model [16] are not valid in a GaAs bipolar transistor (ballistic regime, low-dimension, low/moderate carrier density, cryogenic lattice temperature, etc.…”

Noise-induced resonance-like phenomena in InP crystals embedded in fluctuating electric fields

“…The electron velocity fluctuations of hot electrons, moving inside semiconductors structures owing to static or oscillating voltages, have been extensively investigated during recent decades as the growing miniaturization process of microelectronic components causes charge carriers to be driven by increasingly intense electric fields and exhibit a highly nonlinear response [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18].…”