First, we considered absorption enhancements in the GaAs layer due to the planar monolith as a function of the total TiO2 thickness (Figure ). We denote the null structure as the planar monolith with no TiO2 (thickness = 0 nm) and normalized all other absorption values to the null structure absorption. Some oscillatory behavior in the GaAs absorption was observed as a function of the TiO2 thickness as would be expected from thin film interference. The maximum enhancement was observed to be roughly 2.8 times larger than the null structure absorption for a TiO2 layer thickness of 400 nm.