Spatially Correlated, Single Nanomaterial-Level Structural and Optical Profiling of Cu-Doped ZnO Nanorods Synthesized via Multifunctional Silicides

We demonstrate a straightforward and effective method to synthesize vertically oriented, Cu-doped ZnO nanorods (NRs) using a novel multipurpose platform of copper silicide nanoblocks (Cu(3)Si NBs) preformed laterally in well-defined directions on Si. The use of the surface-organized Cu(3)Si NBs for ZnO NR growth successfully results in densely assembled Cu-doped ZnO NRs on each NB platform, whose overall structures resemble thick bristles on a brush head. We show that Cu(3)Si NBs can uniquely serve as a catalyst for ZnO NRs, a local dopant source of Cu, and a prepatterned guide to aid the local assembly of the NRs on the growth substrate. We also ascertain the crystalline structures, optical properties, and spectroscopic signatures of the Cu-doped ZnO NRs produced on the NBs, both at each module of NRs/NB and at their ensemble level. Subsequently, we determine their augmented properties relative to the pristine form of undoped ZnO NRs and the source material of Cu(3)Si NBs. We provide spatially correlated structural and optical data for individual modules of Cu-doped ZnO NRs assembled on a Cu(3)Si NB by resolving them along the different positions on the NB. Ensemble-averaged versus individual behaviors of Cu-doped ZnO NRs on Cu(3)Si NBs are then compared. We further discuss the potential impact of such ZnO-derived NRs on their relatively unexplored biological and biomedical applications. Our efforts will be particularly useful when exploiting each integrated module of self-aligned, Cu-doped ZnO NRs on a NB as a discretely addressable, active element in solid-state sensors and miniaturized luminescent bioprobes.