Figure 1

Conceptual Schematic of Superlattice.

(a) The structure of the superlattices. (TCO layers (n₁) of 10 nm interspersed with low n (n₂) layers of 2.5 nm to 10 nm thickness). (b) The optical response of the superlattice, namely an effective medium of refractive index index n₁ > n > n₂.