Broadband antireflection property of silicon nanocone arrays with porous sidewalls fabricated by Ag-catalyzed etching

Fan Bai,Mwenya Trevor,Yan Zhang,Robert Hoye,Meicheng Li,Yingfeng Li,Zhiqiang Duan

doi:10.1063/1.4990456

Abstract

Siliconnanocone (SiNC) arrays with porous sidewallswere successfully fabricated through a simple, low-cost Ag-catalyzed etching method. By electron spin resonance technique and TEM analysis, it has been verified that the formation of porous SiNC arrays is due to the gradual dissolution of the pristine Ag nanoislands as they sank into the Si and the lateral etching of the regenerated Ag nanoparticles to the SiNC sidewalls. Theoretical calculation results suggest that the reflectance of the porous SiNC arrays is much lower than that of the smooth SiNC arrays over wide wavelengths ranging from 300nm to 1700nm. The long-wavelength reflectance can be further suppressed by increasing surface porosity of the SiNCs and their length. Experimental test results show the lowest average reflectance of 1.7% in the wavelength range of 300-1000nm while approximately 30% in the wavelength ranges of 1200-1700nm, which is generally consistent with the theoretical results. This shows that the porous SiNC arrays had excellent broadband antireflection properties, making them attractive for a wide range of potential applications in Si-based optoelectronic devices.

Highlights

Combining with the above structural advantages, we find that a composite structure of porous silicon naoncone (SiNC) arrays is an effective approach to achieve the goal of broadband antireflection
The successful growth of porous SiNC arrays using the Ag-catalyzed etching method is illustrated by the images of Fig. 1
We have reported a simple Ag-assisted chemical etching approach for the fabrication of the porous SiNC arrays

Summary

Introduction

Surface antireflection techniques are important for improving the performance of many optoelectronic devices such as light emitting diodes, light sensors and solar cells.[1,2,3,4] In recent years, Si nanowire (SiNW) arrays have developed to be one of the most promising antireflection materials.[5,6,7,8,9,10] Usually, the SiNW arrays can suppress reflection in the wavelength range of 300-1000 nm but they are relatively poor in the wavelength range of 1200-1700 nm.[11,12] the development of SiNW arrays with broadband antireflection properties is necessary.To achieve the goal of broadband antireflection, an effective approach is structural optimization of SiNW arrays. Broadband antireflection property of silicon nanocone arrays with porous sidewalls fabricated by Ag-catalyzed etching

Results

Conclusion