Effects of silver catalyst concentration in metal assisted chemical etching of silicon

Abstract

A systematic investigation is performed to determine the effects of the concentration of silver on metal assisted chemical etching (MaCE) on nanostructure formation mechanisms on silicon as well as their resultant optical properties. Silver nitrate concentrations of 0.008M, 0.004M, 0.003M and 0.002M with hydrogen fluoride were used for the preparation of p-type silicon nanostructures. Experimentally it is observed that when the catalysis molarity concentration is decreased in the etching processes, it resulted in macro, micro and nanostructures from 140 to 60 nm, respectively over the concentrations investigated. A detailed investigation of the optical and structure provided insight into the physics of their formation. In addition, the results show the silicon nanostructures formed black silicon where in the visible region of the spectrum the reflectance dropped by an order of magnitude. The results indicate MaCE is a promising approach to the manufacturing of antireflection coatings on black silicon-based solar photovoltaic cells. MaCE is a simple and scalable approach to enhance the optical absorption of silicon and improve the overall efficiency of the solar cell without adding significantly to the complexity, capital expenditure or cost of production.

Influence of metal assisted chemical etching time period on mesoporous structure in as-cut upgraded metallurgical grade silicon for solar cell application

“…Graded mesoporous Si nanostructures have previously been observed to exhibit reduced recombination losses compared to Si nanowires (SiNWs) [12]. Optimized silver loading conditions were utilized to obtain mesoporous Si, more detail on the effect of silver loading on the nanostructure morphology can be found elsewhere [25]. Figure 1(a) shows the morphology and surface coverage of Ag nanoparticles (AgNPs) on CP5 polished-reference sample.…”

Economic Advantages of Dry-Etched Black Silicon in Passivated Emitter Rear Cell (PERC) Photovoltaic Manufacturing

“…Furthermore, b-Si allows the adoption of the diamond wire sawing technology for mc-Si block wafering [25], which is broadly used for Cz-Si ingot wafering since it reduces the kerf-losses compared to the slurry-based wafering. Note that other b-Si etching technologies currently employed in the PV industry require additional steps for the b-Si etching process, i.e., metal-assisted chemical etching (MACE) [32,41,42] or atmospheric dry etching (ADE) [43]. Furthermore, it has been shown that black mc-Si etched by DRIE can be directly effectively passivated via double-side atomic layer deposition (ALD) [44,45], which further contributes to reducing the number of processing steps necessary for mc-Si PERC cells.…”

Black silicon quality control by conditions of nickel-assisted etching of crystalline silicon surfaces in photovoltaic devices

“…Black-Si was commonly accepted as the nano-and micro-structured silicon surfaces that effectively suppress reflection, while simultaneously enhancing the scattering and absorption of light and a black look instead of a silver-gray look of pure silver wafer [3]. Until now, diverse methods have been proposed for the formation of black-Si including reactive ion etching (RIE) [4], metal-assisted etching with gold [5] or silver [6] nanoparticles, electrochemical etching, etc. The black-Si formation using one- [7] or two- [8] step nickel nanoparticlesassisted etching was also demonstrated.…”