Enhanced Current Transportation in Siliconriched Nitride (SRN)/Silicon-riched Oxide (SRO) Multilayer Nanostructure

Abstract

Abstract A novel structure of silicon-riched nitride (SRN)/silicon-riched oxide (SRO) is proposed and prepared using RF reactive magnetron co-sputtering. High temperature annealing of SRN/SRO multilayers leads to formation of Si nanocrystals (NC) from isolating SRN and SRO layers simultaneously, which efficiently improves carrier transport ability compared to conventional SRN/Si3N4 counterpart. Micro-Raman scattering analysis reveals that SRN layer has dominating number of denser and smaller Si NCs, while SRO layer has relatively less, sparser and bigger Si NCs, as confirmed by high resolution transmission electron microscopy observation. The substitute SRO layers for Si3N4 counterparts significantly increase the amount of Si NCs as well as crystallization ratio in SRN layers; while the average Si NC size can be well controlled by the thickness of SRN layers and the content of N, and hence an obvious stronger absorption in UV region for the novel structure can be observed in absorption spectra. The I–V characteristics show that the current of hybrid SRN/SRO system increases up to 2 orders of magnitude at 1 V and even 5 orders of magnitude at 4 V compared to that of SRN/Si3N4 structure. Si NCs in SiOy layers provide a transport pathway for adjacent Si NCs in SiNx layers. The obvious advantage in carrier transportation suggests that SRN/SRO hybrid system could be a promising structure and platform to build Si nanostructured solar cells.