Fabrication and photoluminescence of AlGaAs/GaAs quantum wire superlattices on V-grooved substrate

An AlGaAs(90 Angstrom)/GaAs(45 Angstrom) quantum wire superlattice (QWR-SL) with excellent size uniformity is grown on a 4.8 mu m pitch V-grooved substrate by flow rate modulation epitaxy at a specific growth temperature (similar to 630 degrees C). In the low temperature (12 K) photoluminescence spectrum of the AlGaAs(90 Angstrom)/GaAs(45 Angstrom) QWR-SL, two excited subband emission peaks are observed at an excitation power density at least about four orders of magnitude lower than that needed for the observation of similar peaks from the single quantum wire (SQWR) reference sample. Another two side-peaks are also observed at the long wavelength side of the ground subband peak whose energy separations from the excited subband peaks are very close to the energies of GaAs optical phonons, implying the possibility of participation of optical phonons in the radiative transition processes of the QWR-SL. The ground subband emission peak of the QWR-SL sample shows a radiative lifetime (similar to 2.1 ns) almost four times longer than that of the SQWR sample. The above observations suggest that the carrier relaxation processes and the radiative transition probability of the QWR-SL seem to be considerably modified against the SQWR structure. (C) 1997 Academic Press Limited.