Protected Light-Trapping Silicon by a Simple Structuring Process for Sunlight-Assisted Water Splitting
Abstract
Macroporous layers are grown onto n-type silicon by successive photoelectrochemical etching in HF containing solution and chemical etching in KOH. This specific latter treatment gives highly antireflective properties of the Si surface. The duration of the chemical etching is optimized to render the surface as absorbent as possible and the morphology of the as-grown layer is characterized by scanning electron microscopy. Further functionalization of such structured Si surface is carried out by atomic layer deposition of a thin conformal and homogenous TiO 2 layer that is crystallized by an annealing at 450°C. This process allows using such surfaces as photoanodes for water oxidation. The 40 nm-thick TiO 2 film acts 2 indeed as an efficient protective layer against the photocorrosion of the porous Si in KOH, enhances its wettability and enlarge the light absorption of the photoelectrode. The macroporous Si has a beneficial effect on water oxidation in 1 M KOH and leads to a considerable negative shift of onset potential of ~400 mV as well as a 50 % increase in photocurrent at 1 V vs SCE.
Keywords
Black silicon
Photo-anodes
Functionalizations
Nano structuration
Photo-electrochemical etching
Structuring process
Porous silicon
Water splitting
Antireflective properties
Titanium dioxide
Semiconducting silicon
Scanning electron microscopy
Silicon
Photoelectrochemical cells
Light absorption
Hydrofluoric acid
Electrochemistry
Electromagnetic wave absorption
Electrochemical etching
Deposition
Atomic layer deposition
Black Silicon
Electrochemical Etching
Atomic Layer Deposition
Nanostructuration
Photoanode
Water Splitting
Photoelectrochemical Cells
Domains
Chemical Sciences| Origin | Files produced by the author(s) |
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