Pair-groove-substrate GaAs/AlGaAs multiquantum well lasers by molecular beam epitaxy.

We investigated molecular beam epitaxial growth characteristics on (001) GaAs substrates with a pair of etched grooves along the <110> direction. It is found that, as the growth proceeds, the mesa width between the pair of grooves gradually decreases and that the grown mesa surface becomes slightly concave. These results offer great advantages for precisely defining the lateral width of index guided lasers during growth. A pair-groove-substrate GaAs/AlGaAs multiquantum well laser has been newly developed, which shows stable fundamental transverse mode oscillation and a high external differential quantum efficiency of 68% as well as a low threshold current of 23 mA. [ABSTRACT FROM AUTHOR]