Wide bandgap aeromaterials and prospects for their applications

Abstract

We report on the fabrication of aeromaterials based on GaN, Ga2O3, TiO2 and Zn2TiO4 using hydride vapor phase epitaxy (HVPE) or Atomic Layer Deposition (ALD) approaches. The fabrication process is based on growth of the preferred material on sacrificial templates consisting of interconnected ZnO microtetrapods. During the epitaxial growth of GaN at high temperatures and corrosive environment, the ZnO is etched away and, consequently, hollow microtetrapods with the wall thickness of the tubes in the range of 20 - 100 nm are obtained. Further, GaN can be transformed into Ga2O3 through an annealing process at temperature as high as 800 ∘C. Alternatively, ALD approach is used to fabricate aero-TiO2 or aero-Zn2TiO4 materials using sacrificial ZnO templates.