Enhanced light coupling into periodic arrays of nanoscale semiconducting fins

Abstract

In this paper, we study experimentally and theoretically the light coupling into periodic arrays of nanoscale semiconducting fins among others to explain its enhancement when increasing the fin pitch, i.e., the spatial periodicity. With Raman spectroscopy on Si fin arrays, we show the enhancement of the light coupling into the fins in arrays of increasing pitch. We prove that this enhancement is due to the excitation of an electromagnetic mode, which is confined and guided inside the fins, and is more efficiently excited as the pitch increases. Finally, we propose a quantitative analytical model describing the physical mechanism responsible for the light coupling into nanoscale semiconducting fins arranged into periodic arrays of narrow sub-60 nm pitch.