Black-Si as a Photoelectrode

Denver P. Linklater, Fatima Haydous, Cheng Xi, Daniele Pergolesi, Jingwen Hu, Elena P. Ivanova, Saulius Juodkazis, Thomas Lippert, and Jurga Juodkazytė;


The fabrication and characterization of photoanodes based on black-Si (b-Si) are presented using a photoelectrochemical cell in NaOH solution. B-Si was fabricated by maskless dry plasma etching and was conformally coated by tens-of-nm of TiO2 using atomic layer deposition (ALD) with a top layer of CoO x cocatalyst deposited by pulsed laser deposition (PLD). Low reflectivity R < 5% of b-Si over the entire visible and near-IR ( λ<2 μ m) spectral range was favorable for the better absorption of light, while an increased surface area facilitated larger current densities. The photoelectrochemical performance of the heterostructured b-Si photoanode is discussed in terms of the n-n junction between b-Si and TiO2.