Hydrodynamic study of terahertz three-dimensional plasma resonances in InGaAs diodes

Abstract

Using a hydrodynamic model self-consistently coupled to a Poisson solver, we investigate the time and frequency response of InGaAs diodes excited at room temperature by an optical photoexcitation presenting a beating in the terahertz frequency domain. The analysis of the main physical quantities, such as the local electric field and the conduction current density, evidences the presence of strong resonances that are interpreted as three-dimensional plasma oscillations excited by the optical beating. By studying the influence of the geometry and doping of the diode, it is shown that, in most cases, the highly doped contacts mainly control the frequency of the plasma mode while the diode length is a crucial parameter to evidence a second resonance related to the diode active region. Moreover, the amplitude of the plasma resonances can be enhanced at high doping levels and by increasing the level of the optical photoexcitation.