title: Tunable Surface Structuration of Silicon by Metal Assisted Chemical Etching with Pt Nanoparticles under Electrochemical Bias.
abstract: An in-depth study of metal assisted chemical etching (MACE) of p-type c-Si in HF/H2O2aqueous solutions using Pt nanoparticles as catalysts is presented. Combination of cyclic voltammetry, open circuit measurements, chronoamperometry, impedance spectroscopy, and 2D band bending modeling of the metal/semiconductor/electrolyte interfaces at the nanoscale and under different etching conditions allows gaining physical insights into this system. Additionally, in an attempt to mimic the etching conditions, the modeling has been performed with a positively biased nanoparticle buried in the Si substrate. Following these findings, the application of an external polarization during etching is introduced as a novel efficient approach for achieving straightforward control of the pore morphology by acting upon the band bending at the Si/electrolyte junction. In this way, nanostructures ranging from straight mesopores to cone-shaped macropores are obtained as the Si sample is biased from negative to positive potentials. Remarkably, macroscopic cone-shaped pores in the 1-5 μm size range with a high aspect ratio (L/W ∼ 1.6) are obtained by this method. This morphology leads to a reduction of the surface reflectance below 5% over the entire VIS-NIR domain, which outperforms macrostructures made by state of the art texturization techniques for Si solar cells.
authors: Institut de Chimie et des Matériaux Paris-Est, CNRS, Université Paris-Est , 2-8 rue Henri Dunant, 94320 Thiais, France.
authors: Encarnación
authors: E
authors: Torralba
authors: Group of electrical engineering - Paris, UMR CNRS 8507, Centrale Supélec, Univ. Paris-Sud, Université Paris-Saclay, Sorbonne Universités, UPMC Université Paris 06 , 3 & 11 rue Joliot-Curie, Plateau de Moulon, 91192 Gif-sur-Yvette CEDEX, France.
authors: Sylvain
authors: S
authors: Le Gall
authors: Group of electrical engineering - Paris, UMR CNRS 8507, Centrale Supélec, Univ. Paris-Sud, Université Paris-Saclay, Sorbonne Universités, UPMC Université Paris 06 , 3 & 11 rue Joliot-Curie, Plateau de Moulon, 91192 Gif-sur-Yvette CEDEX, France.
authors: Raphaël
authors: R
authors: Lachaume
authors: Institut d'Électronique, de Microélectronique et de Nanotechnologie, UMR CNRS 8520, Université de Lille 1 - Sciences et Technologies , Avenue Henri Poincaré, CS 60069, 59652 Villeneuve d'Ascq cedex, France.
authors: Vincent
authors: V
authors: Magnin
authors: Institut d'Électronique, de Microélectronique et de Nanotechnologie, UMR CNRS 8520, Université de Lille 1 - Sciences et Technologies , Avenue Henri Poincaré, CS 60069, 59652 Villeneuve d'Ascq cedex, France.
authors: Joseph
authors: J
authors: Harari
authors: Institut d'Électronique, de Microélectronique et de Nanotechnologie, UMR CNRS 8520, Université de Lille 1 - Sciences et Technologies , Avenue Henri Poincaré, CS 60069, 59652 Villeneuve d'Ascq cedex, France.
authors: Mathieu
authors: M
authors: Halbwax
authors: Institut d'Électronique, de Microélectronique et de Nanotechnologie, UMR CNRS 8520, Université de Lille 1 - Sciences et Technologies , Avenue Henri Poincaré, CS 60069, 59652 Villeneuve d'Ascq cedex, France.
authors: Jean-Pierre
authors: JP
authors: Vilcot
authors: Institut de Chimie et des Matériaux Paris-Est, CNRS, Université Paris-Est , 2-8 rue Henri Dunant, 94320 Thiais, France.
authors: Christine
authors: C
authors: Cachet-Vivier
authors: Institut de Chimie et des Matériaux Paris-Est, CNRS, Université Paris-Est , 2-8 rue Henri Dunant, 94320 Thiais, France.
authors: Stéphane
authors: S
authors: Bastide
keywords: 2D band bending modeling; Si texturization; c-Si; cone-shaped macropores; cyclic voltammetry; impedance spectroscopy; metal assisted chemical etching; platinum