GaAs/AlAs super-flat interfaces in GaAs/AlAs and GaAs/(GaAs)2 (AlAs)2 quantum wells grown on (4 1 1)A GaAs substrates by MBE

Effectively atomically flat GaAs/AlAs interfaces over a macroscopic area ("super-flat interfaces") have been realized in GaAs/AlAs and GaAs/(GaAs)(2) (AlAs)(2) quantum wells (QWs) grown on (411)A GaAs substrates by molecular beam epitaxy (MBE). A single and very sharp photoluminescence (PL) peak was observed at 4.2 K from each GaAs/AlAs or GaAs/(GaAs)(2) (AlAs)(2) QW grown on (411)A GaAs substrate. The full-width at half-maximum (FWHM) of a PL peak for GaAs/AlAs QW with a well width (L-w) of 4.2 nm was 4.7 meV and that for GaAs/(GaAs)(2) (AlAs)(2) QW with a smaller well width of 2.8 nm (3.9 nm) was 7.6 meV (4.6 meV), which are as narrow as that for an individual splitted peak for conventional GaAs/AlAs QWs grown on (100) GaAs substrates with growth interruption. Furthermore, only one sharp peak was observed for each GaAs/(GaAs)(2) (AlAs)(2) QW on the (411)A GaAs substrate over the whole area of the wafer (7x7mm(2)), in contrast with two- or three-splined peaks reported for each GaAs/AlAs QW grown on the (100) GaAs substrate with growth interruption. These results indicate that GaAs/AlAs super-flat interfaces have been realized in GaAs/AlAs and GaAs/(GaAs)(2) (AlAs)(2) QWs grown on the (411)A GaAs substrates. (C) 1998 Elsevier Science B.V. All rights reserved.