  Plasmonic devices have advanced significantly in the past decade. Being one
of the most intriguing devices, plamonic nanolasers plays an important role in
biomedicine, chemical sensor, information technology, and optical integrated
circuits. However, nanoscale plasmonic devices, particularly in ultraviolet
regime, are extremely sensitive to metal and interface quality, which renders
the development of ultraviolet plasmonics. Here, by addressing the material
issues, we demonstrate a low threshold, high characteristic temperature
metal-oxide-semiconductor ZnO nanolaser working at room temperature. The
template for ZnO nanowires consists of a flat single-crystalline aluminum film
grown by molecular beam epitaxy and an ultra-smooth Al2O3 spacer layer prepared
by atomic layer deposition. By effectively reducing surface plasmon scattering
loss and metal intrinsic absorption loss, the high-quality metal film and sharp
interfaces between layers boost the device performance. Our work paves the way
for future applications using ultraviolet plasmonic nanolasers and related
devices.
