Semiconductor nanowires are widely considered to be the next frontier in the drive towards ultra-small, highly efficient coherent light sources. While NW lasers in the visible and ultraviolet have been widely demonstrated, the major role of surface and Auger recombination has hindered their development in the near infrared. Here we report infrared lasing up to room temperature from individual core-shell GaAs-AlGaAs nanowires. When subject to pulsed optical excitation, NWs exhibit lasing, characterized by single-mode emission at 10 K with a linewidth o60 GHz. The major role of non-radiative surface recombination is obviated by the presence of an AlGaAs shell around the GaAs-active region. Remarkably low threshold pump power densities down to B760 W cm À 2 are observed at 10 K, with a characteristic temperature of T 0 ¼ 109 ± 12 K and lasing operation up to room temperature. Our results show that, by carefully designing the materials composition profile, high-performance infrared NW lasers can be realised using III/V semiconductors.

Reliable technologies for the monolithic integration of lasers onto silicon represent the holy grail for chip-level optical interconnects. In this context, nanowires (NWs) fabricated using III-V semiconductors are of strong interest since they can be grown site-selectively on silicon using conventional epitaxial approaches. Their unique one-dimensional structure and high refractive index naturally facilitate low loss optical waveguiding and optical recirculation in the active NW-core region. However, lasing from NWs on silicon has not been achieved to date, due to the poor modal reflectivity at the NW-silicon interface. We demonstrate how, by inserting a tailored dielectric interlayer at the NW-Si interface, low-threshold single mode lasing can be achieved in vertical-cavity GaAs-AlGaAs core-shell NW lasers on silicon as measured at low temperature. By exploring the output characteristics along a detection direction parallel to the NW-axis, we measure very high spontaneous emission factors comparable to nanocavity lasers (β = 0.2) and achieve ultralow threshold pump energies ≤11 pJ/pulse. Analysis of the input-output characteristics of the NW lasers and the power dependence of the lasing emission line width demonstrate the potential for high pulsation rates ≥250 GHz. Such highly efficient nanolasers grown monolithically on silicon are highly promising for the realization of chip-level optical interconnects.

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