Increasing the output power of a heavily doped terahertz quantum cascade laser by avoiding the subband misalignment

A significant enhancement in the output power of a GaAs-based terahertz quantum cascade laser (THz QCL) was achieved by implementing a relatively high impurity doping concentration. The QC structure was precisely designed using the nonequilibrium green function method by considering the band bending effect caused by a higher doping concentration. This enabled us to avoid the subband misalignment induced by the strong band bending effect, to provide efficient carrier transport even at high doping concentrations, and to improve the output power. The maximum output power of a GaAs/Al0.16Ga0.84As 3.5 THz-band QCL at 10K was enhanced from 390 to 600mW by increasing the doping concentration at the depopulation layers from 6x10(16) to 1.2x10(17)cm(-3). The average power of 21mW was achieved by implementing the appropriate pulse drive conditions.

Automated summary

By implementing a relatively high impurity doping concentration, the output power of a GaAs-based terahertz quantum cascade laser was significantly enhanced.