Download or read book III-nitride Nanowire Photoelectrodes written by Shizhao Fan and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "The photoelectrochemical (PEC) approach of converting solar energy into fuels holds significant potential to establish a sustainable energy system. Tremendous effort has been devoted to metal oxide based PEC systems. However, it remains elusive to reach the calibre for application in terms of efficiency, stability and scalability, due to the intrinsic limits of metal oxide light absorbers. Herein, we demonstrate the versatility of indium gallium nitride (InGaN) alloys grown by plasma-assisted molecular beam epitaxy (PA-MBE) for the purpose of water splitting under sunlight. Using tunnel junction nanowires, we realize a monolithically integrated InGaN-nanowire/Si tandem photocathode with dramatically improved efficiency and stability compared to other Si-based photocathodes. Besides, we establish a growth window to produce high quality InGaN alloy nanowires with indium content as high as 50%, which unprecedentedly extends the absorption edge to ~700 nm and leads to the highest photocurrent of InGaN photoelectrodes under AM1.5G one sun illumination. Based on such InGaN nanowires, we further construct an InGaN-nanowire/Si tandem photoanode with an energy bandgap configuration approaching the ideal values of 1.75 eV (top cell) and 1.13 eV (bottom cell) for tandem photovoltaic devices. Such an innovation brings us one step closer to unassisted PEC water splitting with a solar-to-hydrogen (STH) efficiency above 20%. We have successfully coupled the tandem photoanode with NiFeOx water oxidation co-catalyst, reaching a peak STH of 1.3% for water splitting in strong base electrolyte. In addition, we explore the photocatalytic properties of GaN nanowires for the formation and cleavage of C-H bond. Under UV illumination, photocatalytic CO2 reduction towards CO and CH4 is observed on GaN nanowires with Pt nanoparticles as co-catalyst. The difficulty of C-H bond formation on GaN nanowires inspires us to study the cleavage of C-H bond on the surface of GaN nanowires under UV illumination, which leads to the photocatalytic conversion of CH4 to benzene." --