With an eye towards moving the photoabsorption spectrum closer to that of solar radiation and creating a more regular material for water splitting, Caccamo et al. have recently fabricated crystalline InGaN/GaN core-shell nanorods with a relatively constant (0.30\(\pm\)0.04) indium fraction\cite{Caccamo_2014}. The material has not yet been tested, but the proposed advantages are many: as relatively large nanorod arrays, they have quite a large surface area, and the reduced quantity of recombination-center defects, which will decrease the efficiency of a photocatalyst, and thus hinder any attempts to split water and separate hydrogen.

Finally, to show that p-doped InGaN nanowires were just as useful as their n-doped cousins, Kibria et al. followed up their 2013 paper with another, this time demonstrating the usefulness of the p-doping in tackling the surface band-bending problem\cite{Kibria_2015}. They first demonstrated that band-bending– the shifting in energy band edges in a semiconductor in the presence of metal\cite{Zhang_2012}– has a noticeable effect on the oxidation and reduction reactions that take place on doped InGaN, helping some and hindering others. Kibria et al. reasoned that manipulating this band bending through precise doping could help the efficiency of water splitting by GaN/InGaN nanowires.

Kibria et al. first investigated the band structure by recording angle-resolved x-ray photoelectron spectroscopy, and when the surface was shown to be conducive to downward-bending p-doping, they doped their structure with magnesium and attempted water splitting. The result was a photocatalyst that showed high levels of energy conversion efficiency, absorbed photon conversion efficiency, and apparent quantum efficiency, and showed the power of band-bending in optimizing the function of catalysts.