Low-threshold strain-compensated InGaAs/(In,Al)GaAs multi-quantum wellnanowire lasers emitting near 1.3 μm at room temperature

Realizing telecom-band lasing in GaAs-based nanowires (NW) with low bandgap gain mediahas proven to be notoriously difficult due to the high compressive strain built up in theactive regions. Here, we demonstrate an advanced coaxial GaAs-InGaAs multi-quantum well(MQW) nanowire laser that solves previous limitations by the introduction of a straincompensating InAlGaAs buffer layer between the GaAs core and the MQW active region. Usinga buffer layer thickness comparable to the core diameter applies a significant tensilestrain to the GaAs core which efficiently minimizes the compressive strain in the InGaAsMQW and enables large In-content without plastic relaxation. Experimental verification isshown for NW-lasers with an In-content of up to 40% in the MQW, evidencing a clearstrain-relieved redshift of the lasing emission and a strong reduction of the lasingthreshold compared to highly strained MQWs in state-of-the-art GaAs NW-lasers. This way weachieve optically pumped room temperature lasing operation with a threshold below 50 μJcm−2 in the telecom O-band close to 1.3 μm.