InGaN/GaN nanowires for water splitting
- Photocatalysis of water is a process that uses light to break down water into its basic components, hydrogen and oxygen,
with the aid of a photochemical catalyst. Under illumination, photons absorbed by the catalyst, generate charge carriers (electron-hole pairs)
which are then transported to the reaction sites to catalyze the targeted oxidation and reduction reactions. The catalysts used in water
photocatalysis are generally semiconducting materials such as titanium dioxide (TiO2) or other metal oxides
- InGaN/GaN alloys have a band gap that can cover the visible range by varying the indium composition. It is thus estimated that
with 50% Indium (Eg≈1.7 eV) it is possible to collect a large part of the solar spectrum while having valence and conduction band levels
ideally placed for water oxidation and reduction reactions. Theoretical solar-to-hydrogen (STH) conversion efficiencies of 10% could thus
be achieved, far superior to metal oxides.
- Device efficiency can also be enhanced by modifying material morphology. The use of nanostructures such as nanowires increases the active
surface area compared with a planar layer, ensuring a greater number of sites available for photoelectrochemical reactions. Moreover, nanowire
growth results in a material with better crystalline quality, minimizing non-radiative recombination centers
- GaN/InGaN core-shell nanowires are grown at CRHEA using organometallic vapor-phase epitaxy, and their photoelectrochemical characterization
is carried out in collaboration with the Photocatalysis and Photoconversion team at ICPEES.
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