Effects of silver nanoparticles layer thickness towards properties of black silicon fabricated by metal‑assisted chemical etching for photovoltaics

摘要

This paper investigates effects of silver nanoparticles (Ag NPs) layer thickness towards properties of black silicon (b-Si)fabricated by two-step metal-assisted chemical etching for potential application in photovoltaic (PV) devices. Ag NPswith different layer thicknesses (1.3–5.1 μm) are deposited on monocrystalline silicon (mono c-Si) wafers by electrolesschemical deposition in AgNO_3/HF aqueous solution for 10–40 s. This is followed by etching in HF:H_2O_2:DI H_2Oaqueoussolution for 20 s. Surface morphological investigation confirms presence of b-Si nanowires with height of 250–577 nmand diameter of 100–200 nm. The b-Si nanowires suppress broadband reflectance from the wafers over 300–1100 nmwavelength region, due to refractive index grading effect. Sample with Ag NPs layer thickness of 5.1 μm exhibits b-Sinanowires with average height of 577 nm and average diameter of 200 nm after etching. This sample demonstrates thelowest weighted average reflectance of 5.5% compared to other samples. This sample exhibits absorption of 96.5% atwavelength of 600 nm. The enhanced broadband light absorption leads to maximum potential short-circuit currentdensity (J_(sc(max))) of 39.7 mA/cm~2, or 51% relative enhancement compared to planar reference sample.