Morphological and Optical Properties of Silicon Nanostructure, Obtained by One Step Ag-assisted Chemical Etching

میادة حسین,Samir Ahmad

doi:10.33899/rjs.2021.169977

Abstract

Silver-assisted one-step chemical etching (AACE) is a low-cost, straightforward method for producing silicon nanostructures to improve their light absorption; it includes the etching of the wafers in aqueous hydrofluoric acid (HF), silver nitrate (AgNO3) and nitric acid (HNO3) solution. Influence of various parameters, such as AgNO3 concentration (0.47, 0.58, and 1.17 mM), HF concentration (0.67, 0.9, and 1.129 M), HNO3 concentration (0.12, 0.24, and 0.37 M), etching temperature (40, 50, and 60oC), and etching time (4, 5, and 6 min), on the Morphological and optical properties of silicon wafers were investigated. The results show that these parameters have a main role in determining the nanostructure size. The reflection measurements show that the minimum reflectance with 11% achieved with 0.58 mM AgNO3, 1.129 M HF, and 0.12M HNO3 recipe. Field Emission Scanning Electron Microscopy (FESEM) appears that the morphology of the manufactured silicon is semi-spherical nanostructures with the formation of the porous surface on the surface of the wafers.

Highlights

The reflection increases with the increase in the concentration of AgNO3 in the etching solution from 14.10% to 19.25%, where when the concentration of silver increases, continuous nano-layers are formed, which prevent the reaction of the hydrofluoric acid (HF) with SiO2 and reduce the etching rate
The Ag assistance chemical etching process can be explained as rapid oxidation and etching of silicon (Si) by hydrofluoric acid (HF) near metal nanoparticles produced on the surface by electroless deposition
With the increase in the temperature of the etching solution to 45°C, we notice a decrease in the reflection 11.54% Fig. 5(a) where the surface of the wafer becomes a nano-porous structure as in Field Emission Scanning Electron Microscopy (FESEM) image 5(c)

Summary

Introduction

The reflection increases with the increase in the concentration of AgNO3 in the etching solution from 14.10% to 19.25%, where when the concentration of silver increases, continuous nano-layers are formed, which prevent the reaction of the HF with SiO2 and reduce the etching rate.

Results

Conclusion