3.3 THz quantum cascade laser based on a three GaAs/AlGaAs quantum-well active module with an operating temperature above 120 K

In this work, we have optimized the THz QCL design with an active module based on three GaAs/Al$_{0.18}$Ga$_{0.82}$As quantum wells for high-temperature generation at a frequency of about 3.3 THz. A heterostructure based on the developed design with an active region thickness of 10 $\mu$m was grown by molecular beam epitaxy with a deviation of the active module thickness from the nominal less than 1%. The fabricated THz QCLs with a double metal waveguide demonstrate lasing up to a temperature of 125 K. Investigations of the I–V characteristics, the dependences of the integrated radiation on the current and the lasing spectra showed good agreement with the calculated characteristics.