Characterization of Co-existing In 2 O 3 -ZnO Nanostructures

In this study, we report the simultaneous growth of both In 2 O 3 and ZnO nanostructures on the same substrate when attempting to achieve heavily Zn-doped In 2 O 3 nanowires with Zn. These oxide structures were synthesized by vapor–liquid–solid growth. Scanning electron microscope imaging and transmission electron microscopy shows the presence of nanostructures with different morphologies while energy-dispersive x-ray and x-ray photoelectron spectroscopy study confirms the elemental structure. Room-temperature photoluminescence (PL) study reveals the presence of oxygen vacancies and surface defects in the structures. Emission related to free and bound excitons as well as the donor–acceptor transitions were observed using temperature-dependent PL. Raman spectroscopy measurement using 442-nm non-resonant excitation sources shows the presence of four phonon modes associated with a cubic In 2 O 3 lattice structure along with the observation of the dominant E 2 high and quasi-longitudinal optical phonon modes associated with wurtzite ZnO. We find that the introduction of high zinc content results in the formation of ZnO nanowires in addition to the In 2 O 3 nanowires, and not the formation of a highly doped In 2 O 3 nanowires.