  Nanowire-based plasmonic lasers are now established as nano-sources of
coherent radiation, appearing as suitable candidates for integration into
next-generation nanophotonic circuitry. However, compared to their photonic
counterparts, their relatively high losses and large lasing thresholds still
pose a burdening constraint on their scalability. In this study, the lasing
characteristics of ZnO nanowires on Ag and Al substrates, operating as
optically-pumped short-wavelength plasmonic nanolasers, are systematically
investigated in combination with the size-dependent performance of the hybrid
cavity. A hybrid nanomanipulation-assisted single nanowire optical
characterization combined with high-throughput PL spectroscopy enables the
correlation of the lasing characteristics to the metal substrate and the
nanowire diameter. The results evidence that the coupling between excitons and
surface plasmons is closely tied to the relationship between substrate
dispersive behavior and nanowire diameter. Such coupling dictates the degree to
which the lasing character, be it more plasmonic- or photonic-like, can define
the stimulated emission features and, as a result, the device performance.
