2.2. Simulation for photon absorption
The finite difference time domain (FDTD) algorithm is
widely adopted to solve Maxwell’s equations (Taflove
and Hagness, 2005) and we use this method to analyze
the optical absorption of the nanostructured thin-film solar
cells. In the simulation, plane waves are normally incident
on the cells. The perfectly matched layer (PML) absorbing
boundary condition is imposed on both the top and bottom
boundaries while the periodic boundary condition is
implemented around the side boundaries within the simulation
region. Once obtaining the spatial distribution of the
electromagnetic field, one can obtain the total absorption
in the semiconductor layer as Yahaya et al. (2013):