ROLE OF GROWTH TEMPERATURE IN GSMBE GROWTH OF STRAINED-LAYER INGAAS/GAAS QUANTUM-WELL LASERS

Strained-layer InGaAs/GaAs single quantum well lasers were grown by gas-source molecular-beam epitaxy at growth temperatures in a range of 430 to 610-degrees-C. The optimum growth temperature for the quantum well of the lasers was found to be about 520-degrees-C. If the growth temperature is lower than this value, the threshold current density dramatically increases due to the presence of a high density of non-radiative carrier recombination centers in the quantum well, which give rise to alloy disordering and lattice mismatch defects in the quantum well. If the growth temperature is higher than 520-degrees-C, indium evaporation and segregation become severe during the growth of the quantum well. Thus, the InGaAs/GaAs interfaces become Tough and the threshold current density degrades. In addition, room-temperature photoluminescence was investigated for the samples in detail to clarify the quality of the quantum well.