High characteristic temperature 1.5 µm wavelength laser diode via Sb-based quantum dots in quantum wells

The advent of laser diodes in the 1.55 mu m wavelength region is becoming a hot topic in the field of telecommunications. The growth of strain-engineered Sb-based multi-stacks quantum dots (QDs) on GaAs by molecular beam epitaxy (MBE) is advantageous to restrain its drawback of self-absorption and thus beneficial for preparing efficient laser diodes (LDs). Moreover, owing to a strong electronic coupling between the QDs layers and the quantum wells (QWs), strain-engineered QDs introducing antimony (Sb) with emission wavelength up to 1.5 mu m were achieved at room temperature. The p-type doping can substantially increase the QD laser's ground state gain at room temperature. Based on this simple process, high efficient LD was obtained. The LD was fabricated with a cavity length of 1000 mu m and a stripe width of 100 mu m. The output performance was achieved with threshold current densities of the device as low as 135 A/cm(2), and with high Characteristic Temperatures of 118 K or higher in the temperature range between 20 degrees C and 80 degrees C. The continuous wave operating up to 32 mW were achieved at room temperature (RT).