Optical Properties and Fano Resonance Behavior in Silicon Nanowires with p-n Junctions: Mapping the Junction

Abstract

Silicon nanowires (NWs) with axial homojunctions have exhibited superior forward current density compared to traditional bulk silicon p-n junctions, making them highly promising for photovoltaic applications with minimal absorption losses. In particular, understanding the intricate interplay between dopants and these structures is crucial for enhancing the NW properties. Contactless optical techniques are suitable for NW characterization, in particular micro-Raman spectroscopy permits the analysis of axial p-n junctions in Si NWs using the Fano asymmetry parameter (q). The micro-Raman scan along the NW allows us to distinguish the n-type segment, the charge-depleted region at the p-n junction, and the p-type segment. Micro-Raman spectroscopy allows contactless estimation of the free carrier concentration, together with structural characterization, and the junction characteristics.