Multiple quantum well laser prepared by molecular-beam-epitaxy and device characteristics

Multiple quantum well lasers have been made by a home-made molecular-beam-epitaxy system. At room temperature, the best threshold current density of the broad-area contact device is 3000 A/cm², and proton bombarded stripe geometry MQW laser has a threshold current of 128 mA. Single longitudinal mode operation is also observed in a wide current injection range. The highest external differential quantum efficiency is 34% per facet. Lasing wavelengths are in the range from 8590angstrom to 8640angstrom and far-field optical intensity distribution exhibits a single peak. The characteristic temperature is 202 K near 300 K. The details of molecular beam epitaxial procedures and growth conditions for MQW laser are reported. The investigations on grown materials and devices have shown that the grown AlGaAs materials, especially the doped AlGaAs, are not ideal and result in a not very low threshold current density.