AlGaAs/GaAs stripe laser diodes fabricated on Si substrates by MOCVD

The lasing characteristics of the 7 μm wide oxide stripe double heterostructure lasers grown on Si and on GaAs substrates are measured and compared. The averaged threshold current and differential efficiency on Si are about double and one-half, respectively, of those on GaAs, but those of the best device on Si are almost the same as the standard device on GaAs. The lasing wavelength is almost the same, but the spectrum spreading is larger for those on Si, and the diodes on Si substrates lase in TM or TM + TE modes, while those on GaAs lase only in TE. These phenomena are explained an the basis of strain-induced valence band splitting and the reduction in electron effective mass in the conduction band.