Growth of β-Ga₂O₃and GaN nanowires on GaN for photoelectrochemical hydrogen generation

Abstract

Enhanced photoelectrochemical (PEC) performances of Ga(2)O(3) and GaN nanowires (NWs) grown in situ from GaN were demonstrated. The PEC conversion efficiencies of Ga(2)O(3) and GaN NWs have been shown to be 0.906% and 1.09% respectively, in contrast to their 0.581% GaN thin film counterpart under similar experimental conditions. A low crystallinity buffer layer between the grown NWs and the substrate was found to be detrimental to the PEC performance, but the layer can be avoided at suitable growth conditions. A band bending at the surface of the GaN NWs generates an electric field that drives the photogenerated electrons and holes away from each other, preventing recombination, and was found to be responsible for the enhanced PEC performance. The enhanced PEC efficiency of the Ga(2)O(3) NWs is aided by the optical absorption through a defect band centered 3.3 eV above the valence band of Ga(2)O(3). These findings are believed to have opened up possibilities for enabling visible absorption, either by tailoring ion doping into wide bandgap Ga(2)O(3) NWs, or by incorporation of indium to form InGaN NWs.

Nanoporous GaN for enhanced solar hydrogen production

“…This is significantly greater than the 24 % achieved for the as-grown which is comparable to other GaN based devices. 30,31 All GaN devices show a strong UV absorption as expected (Fig. 4a) with the porous devices A and B, demonstrating a 36 % efficiency gain over the as-grown device.…”

InN/InGaN quantum dot photoelectrode: Efficient hydrogen generation by water splitting at zero voltage

“…Recently, GaN has been revealed as a material well suited for PEC water splitting and studied systematically [13][14][15][16][17]. On top, the progress in fabricating and characterizing InGaN nanostructures opens up new opportunities.…”

Facile Fabrication of Ga2O3 Nanorods for Photoelectrochemical Water Splitting

“…RF sputtered Ga 2 O 3 films were also demonstrated to generate H 2 from water with good stability . In addition, Ga 2 O 3 nanowires grown on GaN substrate owned a defect band centered 3.3 eV above the valence band and achieved decent conversion efficiencies of 0.906% . These researches prove Ga 2 O 3 as a promising photoelectrode for PEC.…”