Large Barrier InAs Quantum Dots with Efficient Room Temperature Photon Emission at Telecom Wavelengths

The effect that barrier material has on the temperature dependence of photoluminescence of InAs/AlGaInAs/InP quantum dots in the telecom C-band (∼1550 nm) is reported. Increasing Al content in the barrier material, (AlxGa1-x)0.53In0.47As, creates less temperature sensitivity and enhances the high temperature relative quantum yield. Three samples, with x = 0.51, 0.75, and 1, have room temperature relative quantum yield values of 2.0%, 3.7%, and 41.0%, respectively, when compared to low temperature values. Determination of thermal activation energies shows that the loss of relative quantum yield is due to thermal escape of holes from the quantum dots to the barrier. More aluminum-rich barriers require higher temperatures to depopulate the ground state of the quantum dots, which leads to better high temperature emission. These results can guide future designs of telecom C-band quantum dot devices.