Light-Induced Adaptive Structural Evolution in Gallium Nitride Nanowire/Nickel Hydroxide Symbiotic System in Photoelectrochemical Environment

The adaptability of living organisms to dynamically adjust their biological behavior in response to fluctuating surroundings is a prerequisite for their evolutionary success. However, artificially-synthesized materials, especially semiconductors, have not been able to replicate such adaptability due to their inherent physical rigidity and lack of intrinsic structural responsiveness to external stimuli. Herein, an adaptive structural evolution in group-III-nitride semiconductors is demonstrated by constructing an AlGaN-nanowire/Ni(OH)2 symbiotic-system, resulting in self-improved optoelectronic characteristics. The mutualistic interplay between AlGaN and Ni(OH)2 nanostructure leads to the adaptive evolution of crystalline-facets of AlGaN-nanowires, along with self-optimization of Ni(OH)2 nanocrystals upon photon-irradiation during its operation. Specifically, the nanowire-surfaces dynamically evolve during Ni(OH)2 photo-deposition, removing the (0001 over bar $\bar{1}$) plane while exposing the (101 over bar 1 over bar $\bar{1}\bar{1}$), which facilitates carrier transport at AlGaN/Ni(OH)2 interface. Moreover, light-induced electrons generated from AlGaN-nanowires then partially reduce Ni2+ ions in the Ni(OH)2 nanostructure into Ni0 nanometals, which further boosts the proton reduction thermodynamics, generating an unusual self-improving photocurrent from -59.6 to -101.6 mu A cm-2. Such a "symbiotic system," which is barely observed in conventional semiconductors, provides a promising avenue toward realizing smart adaptive semiconductors that are capable of dynamic structural evolution to fully unleash their potential for emerging optoelectronic and artificial-photocatalysis applications. The occurrence of adaptive structural evolution in solid-state semiconductors is observed by constructing an AlGaN-nanowire/Ni(OH)2 symbiotic system. The mutualistic interplay between the AlGaN alloy and Ni(OH)2 nanostructure leads to the adaptive evolution of crystalline facets of AlGaN-nanowires along with an in situ self-optimization of Ni(OH)2 structure upon ultraviolet irradiation, resulting in enhanced charge transfer and a self-optimizing photoresponse.image