  Semiconductor nanowire lasers can produce guided coherent light emission with
miniaturized geometry, bringing about new possibility for a variety of
applications including nanophotonic circuits, optical sensing, and on-chip and
chip-to-chip optical communications. Here, we report on the realization of
single-mode room-temperature lasing from 890 nm to 990 nm utilizing a novel
design of single nanowires with GaAsSb-based multiple superlattices as gain
medium under optical pumping. The wavelength tunability with comprehensively
enhanced lasing performance is shown to result from the unique nanowire
structure with efficient gain materials, which delivers a lasing quality factor
as high as 1250, a reduced lasing threshold ~ 6 kW cm-2 and a high
characteristic temperature ~ 129 K. These results present a major advancement
for the design and synthesis of nanowire laser structures, which can pave the
way towards future nanoscale integrated optoelectronic systems with stunning
performance.
