Open AccessAntireflective silicon surface with vertical-aligned silicon nanowires realized by simple wet chemical etching processes
Author(s) -
YungJr Hung,
SanLiang Lee,
Kai-Chung Wu,
Yian Tai,
Yen-Ting Pan
Publication year - 2011
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.19.015792
Subject(s) - materials science , etching (microfabrication) , silicon , optoelectronics , isotropic etching , fabrication , nanowire , absorption (acoustics) , optics , reflection (computer programming) , anti reflective coating , scattering , silicon nanowires , nanotechnology , composite material , computer science , medicine , alternative medicine , physics , layer (electronics) , pathology , programming language
Silicon antireflection is realized with vertical-aligned SiNWs by using improved metal-induced etching technique. The spectral responses of the transmission, reflection, and absorption characteristics for the SiNWs of different lengths are investigated. In order to realize short SiNWs to provide sufficiently low reflection, a post chemical etching process is developed to make the nanowires have a larger length fluctuation and/or tapered structure. The use of short SiNWs can allow a faster process time and avoid the sub-bandgap absorption that frequently occurs in long nanowires. Short SiNWs can also provide more compatible material structure and fabrication procedures than long ones can for applying to make optoelectronic devices. Taking the applications to solar cells as examples, the SiNWs fabricated by the proposed technique can provide 92% of solar weighted absorption with about 720 nm long wires because of the resultant effective graded index and enhanced multiple optical scattering from the random SiNW lengths and tapered wires after KOH etching.