Investigating the optical absorption of gallium arsenide with gold plasmonic nanodisk array via RCWA- and FDTD-based simulation
Gallium arsenide (GaAs) is a semiconductor material that is widely used in optoelectronic device fabrication. The optical properties of semiconductor materials highly influence the performance of these devices. Particularly, maximizing the optical absorption has been shown to improve the efficiency and performance of the device. In this study, we used gold (Au) plasmonic nanodisks in a rectangular array to improve the optical absorption of GaAs. The enhancement in optical absorption was investigated using finite-difference time-domain (FDTD) and rigorous coupled wave analysis (RCWA)-based simulations. It was shown that the plasmonic nanostructure was able to alter the optical properties of the material. At optimum nanodisk dimensions, a significant increase in the absorbance and absorption coefficient was observed. Moreover, a localized enhancement of the electric field was observed near the plasmonic nanodisks.