Improved performance of 1.3μm multilayer InAs quantum-dot lasers using a high-growth-temperature GaAs spacer layer

The use of a high-growth-temperature $\mathrm{GaAs}$ spacer layer is demonstrated to significantly improve the performance of $1.3\mu \mathrm{m}$ multilayer self-assembled $\mathrm{InAs}∕\mathrm{InGaAs}$ dot-in-a-well lasers. The high-growth-temperature spacer layer inhibits threading dislocation formation, resulting in enhanced electrical and optical characteristics. Incorporation of these spacer layers allows the fabrication of multilayer quantum-dot devices emitting above $1.3\mu \mathrm{m}$ , with extremely low room-temperature threshold current densities and with operation up to $105°\mathrm{C}$ .