Hybrid metal oxide nano‐ and microstructures exhibit novel properties, which make them promising candidates for a wide range of applications, including gas sensing. In this work, the characteristics of the hybrid ZnO‐Bi₂O₃ and ZnO‐Zn₂SnO₄ tetrapod (T) networks are investigated in detail. The gas sensing studies reveal improved performance of the hybrid networks compared to pure ZnO‐T networks. For the ZnO‐T‐Bi₂O₃ networks, an enhancement in H₂ gas response is obtained, although the observed p‐type sensing behavior is attributed to the formed junctions between the arms of ZnO‐T covered with Bi₂O₃ and the modulation of the regions where holes accumulate under exposure to H₂ gas. In ZnO‐T‐Zn₂SnO₄ networks, a change in selectivity to CO gas with high response is noted. The devices based on individual ZnO‐T‐Bi₂O₃ and ZnO‐T‐Zn₂SnO₄ structures showed an enhanced H₂ gas response, which is explained on the basis of interactions (electronic sensitization) between the ZnO‐T arm and Bi₂O₃ shell layer and single Schottky contact structure, respectively. Density functional theory‐based calculations provide mechanistic insights into the interaction of H₂ and CO gas molecules with Bi‐ and Sn‐doped ZnO(0001) surfaces, revealing changes in the Fermi energies, as well as charge transfer between the molecules and surface species, which facilitate gas sensing.

Continued development of GaN-based light emitting diodes is being hampered by constraints imposed by current non-native substrates. ZnO is a promising alternative substrate but it decomposes under the conditions used in conventional GaN metal organic vapor phase epitaxy (MOVPE). In this work, GaN was grown on $\mathrm{Zn}\mathrm{O}∕c\text{-}{\mathrm{Al}}_2{\mathrm{O}}_3$ using low temperature/pressure MOVPE with ${\mathrm{N}}_2$ as a carrier and dimethylhydrazine as a $N$ source. Characterization confirmed the epitaxial growth of GaN. The GaN was lifted-off the $c\text{-}{\mathrm{Al}}_2{\mathrm{O}}_3$ by chemically etching away the ZnO underlayer. This approach opens up the way for bonding of the GaN onto a support of choice.