III–V Semiconductor Materials for Solar Hydrogen Production: Status and Prospects

Following recent developments in photoelectrochemical and photovoltaic–electrosynthetic systems, we present the benefits of III–V semiconductors for solar water splitting. In addition to their interesting light absorption and carrier transport properties, III–V alloys and multijunction structures enable the highest solar-to-hydrogen conversion efficiencies. However, many obstacles still stand in the way of practical realization of III–V solar water-splitting systems. Various surface protection strategies are being developed to address the instability of III–V semiconductors in an electrolyte. Meanwhile, multiple cost-reduction approaches are being implemented, including the use of solar concentration, epitaxial lift-off or spalling for substrate reuse, and monolithic or heterogeneous integration on silicon substrates. All these advances make III–V photoabsorbers a promising route toward decarbonated hydrogen production and pave the way to long-term deployment in real-world applications.