Simulation of terahertz emission by a textured gallium arsenide using the Drude-Lorentz model

Abstract

We investigate the terahertz emission of textured gallium arsenide (GaAs) as a thin film of an effective medium made up of air and GaAs. The Bruggeman Effective Medium Approximation (BEMA) is used to estimate the optical property of the textured region of the GaAs substrate. Calculations for the dynamics of the photocarrier is done using the Drude-Lorentz model (DLM). We found that a GaAs thin film with a volume fraction of 0.60 to 0.64 exhibits the highest terahertz emission. The optimal thickness is found at 104 nm, 319 nm, 544 nm, 778 nm, and 1000 nm. Under the assumptions of BEMA and DLM, we can say that surface texturization is not always beneficial in enhancing THz emission. Texturization of semiconductor surface must be tuned for optimal THz enhancement.