Growth of Single-sided ZnO nanocombs/ML graphene Heterostructures

We report catalyst-free growth of high-density single-sided ZnO nanocombs for the first time on a multi-layer graphene (MLG). Structural analysis based on scanning electron microscope reveals the nanocomb ribbon average diameter and length are about 90–600 nm and 5–60 μm, respectively, while the diameter and length of the comb tooth are about 30–100 nm and 100–700 nm respectively. In general, the length of the teeth decreases gradually from one end of the nanocomb ribbon to another. ZnO crystal growth seems to involve two steps which are the formation of Zn buffer layer/graphene, which works as growth nucleation sites and long nanowires ends with nanocombs structure. Raman and PL optical transitions prove the well-faceted hexagonal structure of ZnO nanocombs as well as the existence of defects such as O vacancies and Zn interstitials. Graphene-based inorganic hybrid nanostructures provide several potential applications in optoelectronics and nanoscale electronics such as nanogenerators, photovoltaic devices, optical devices, and photodetectors.