Enhancing the conductivity of ZnO micro- and nanowire networks with gallium oxide

In this work a successful hybridization strategy for ZnO micro- and nanowire's surface with Ga
₂
O
₃
nano-networks is presented and briefly discussed. The ZnO micro- and nanowires are grown by an upgraded flame transport synthesis (FTS) approach. The ZnO wires have been coated with gallium acetylacetonate (Ga(acac)3) organic solution followed by subsequent annealing in air and argon atmospheres. Depending on the annealing conditions, distinct impacts on the electrical properties of individual hybridized ZnO microwires are observed which demonstrate a remarkable increase in conductivity (factor of 20 for air and 200 for argon environments). Scanning transmission electron microscopy (STEM) in combination with energy-dispersive X-ray spectroscopy (EDX) confirmed that the gallium oxide nanoparticles form, alter the ZnO surface features and might effect a doping in such a way. High-resolution transmission electron microscopy (HRTEM) studies of the hybridized ZnO surface reveal that both the β-/γ-Ga
₂
O
₃
phases are present as nanoinclusions in the top layer. These investigations confirmed noticeable modifications in the ZnO lattice caused by the hybridization with gallium oxide. Moreover, the structural changes in the ZnO surface were traced via Raman spectroscopy examinations revealing an increase in the scattering peaks intensity at 569 cm
^-1
and 646 cm
^-1
which are responsible for the native oxygen vacancies in ZnO and a corresponding blue shift for the E
₂
(high) peak indicates an introduction of strain into ZnO lattice.