LAUSR

In this paper, we report a novel method combining acid vapor etching (AVE) and Lithium (Li) pore-filling aiming to enhance the opto-electrical properties of silicon nanowires (SiNWs). Images provided by both scanning and transmission electron microscopies (SEM and TEM) show that, the silver-Assisted Chemical Etching (Ag-ACE) method provides uniform and vertically aligned SiNWs with smooth sidewalls. AVE treatment leads to the formation of thin porous silicon (pSi) layer covering the initially solid SiNW sidewalls without affecting their initial length. The as-prepared porous SiNWs (pSiNWs) exhibit a quite strong photoluminescence (PL) band centered on 2 eV. An additional immersion of pSiNWs in LiBr aqueous solution leads to a significant change in the surface chemistry and a stable PL emission with fourfold increase in the intensity. The total reflectivity decreases with Li concentration and reaches 1% in the visible range. Simultaneously, the minority carrier lifetime (τeff) of pSiNWs is enhanced from 1.48 to 7.1 µs due to the formation of a stable passivation layer and the saturation of dangling bands. The dark I–V measurement shows a significant decrease of the series resistance from 340 to 85 Ω.