Solution Growth of Screw Dislocation Driven α-GaOOH Nanorod Arrays and Their Conversion to Porous ZnGa₂O₄ Nanotubes

The solution synthesis of ternary metal oxides is difficult due to the competing hydrolysis of metal ions. There are reports of hydro-/solvothermal growth of nanoparticles, but one-dimensional (1D) nanoarrays are less common. Here, we report an alternative and general strategy to circumvent this challenge by converting the 1D binary metal oxide/hydroxide nanostructures initially grown driven by screw dislocations into ternary oxides. Using the α-GaOOH/α-Ga 2 O 3 /ZnGa 2 O 4 wide bandgap transparent conductor materials as a demonstration, we synthesize vertical arrays of high aspect ratio α-GaOOH nanorods (NRs) on conducting substrates with controllable length for the first time using a continuous flow reactor and confirm their growth mechanism to be dislocation-driven. Then the α-GaOOH NR arrays can be converted into porous α-Ga 2 O 3 NR arrays, which can be further converted via a solution method into porous ZnGa 2 O 4 nanotube (NT) arrays due to the Kirkendall effect. This work presents a new and general strategy to prepare 1D nanostructure arrays of various binary and ternary oxides at low cost and large scale, and such facile solution growth and the unique structure of porous ZnGa 2 O 4 NT arrays will facilitate their practical applications.