Optical properties of black silicon prepared by wet etching

Abstract

In this paper, the optical properties of black silicon have been studied. The black silicon samples were fabricated by alkaline etching and metal assisted etching. The micro-columns and nanopores on the silicon surface were obtained in KOH and Au-induced HF/H 2 O 2 solution, respectively. The height and diameter of micro-columns prepared by KOH etching is about 470 nm and 2 lm. In the Au-induced HF/H 2 O 2 etching, the metallic nuclei behave as a cathode and their surrounding area acts as an anode, resulting in nanopores with diameters ranging from 80 to 120 nm. These microstructures formed in the etching process directly affect the optical properties of black silicon such as reflectance, transmittance and absorptance. According to the measurement of integrating sphere detector, the absorptance of the black silicon produced by wet etching remains roughly 90% from 250 to 1,000 nm wavelength, which is almost 150% of the absorptance of conventional silicon. However, the reflectance of black silicon is less than 13% and the transmittance is less than 4%.

Enhanced the light absorptance of stain-etched black Silicon decorated by TiN nanoparticles

“…Stain etching method leads to formation of porous silicon and the main chemical reaction is results in a continus process of oxidation-followed-by-dissolution in which HNO 3 is devoted to injecting holes and oxidizing silicon, and HF for the removal of the formed oxide [8,9]. Figure 2 shows the typical SEM images of stain-etched black silicon in top view at 30°angle for different etching time.…”

“…Texturing silicon surface by laser ablation requires a lot of time and economic cost. Thus, more attention has been paid on other technical means for the fabrication of BSi, such as electrochemical etching [6], reactive ion etching (RIE) [7], stain etching [8,9], metal-assisted etching [10], etc.•. However, BSi materials generated in these approaches wouldn't break the limitation of the large energy bandgap of Si without heavily doped impurity elements, which means the electromagnetic wave with a wavelength over 1100 nm won't generate electro-holes pairs inside semiconductor [11].…”

Optical Properties of Black Silicon: An Analysis

“…18 Due to the local catalytic action of the Au clusters, this treatment leads to nano-scale texturing. 19 For the typical metal-assisted chemical etching process, a Si substrate is partially covered by noble metals which can be obtained by vacuum technology.…”

Facile Fabrication of Self-Similar Hierarchical Micro-Nano Structures for Multifunctional Surfaces via Solvent-Assisted UV-Lasering

“…Recently, techniques based on reactive ion etching (RIE) and metal catalyzed chemical etching (MCCE) have been developed. Nevertheless, they also have some problems, such as costly facility, required operational conditions, and wasted liquid that may be harmful to the natural environment [ 37 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 ]. An appealing technique is that of directly ablating silicon surface to obtain “penguin-like” microstructures via femtosecond lasering in toxic gas atmospheres such as SF 6 , Cl 2 , and H 2 S [ 51 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 ].…”