Photo-induced tunable local oxidation and fragmentation in Pt ultra-nanoclusters functionalized GaN nanotubes.

Large scale square-shaped wurtzite-GaN nanotubes are synthesized by a quasi-vapor-solid process. GaN nanotubes, functionalized with ultra-small Pt nanocluster via green chemistry route, provide extraordinary physicochemical properties instigated by laser power exposure and local ambience. Laser irradiation-induced localized catalytic oxidation and catastrophic photo-fragmentation in individual nanotubes is observed as a result of rapid crystallo-chemical transformation. The auto-amplified electronic cascades inside the Pt nanoclusters, upon exposure to high laser fluency, reinforce strong energy deposition in the proximity of the metal-semiconductor interface. This process leads to ballistic recombination with the available photo-generated O ionized/radical species to yield chemisorbed oxide layer of GaO. It has been demonstrated to bisect or oxidize a selected region of a single GaN nanotube by modulating the incident laser power, gas ambience, and its kinetics. [ABSTRACT FROM AUTHOR]