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Photoluminescence from AlGaAs-GaAs Single Quentum Wells with Growth Interrupted Heterointerfaces Grown by Molecular Beam Epitaxy

Photoluminescence measurements have been carried out for AlGaAs-GaAs single quantum well structures grown by molecular beam epitaxy. At both 77 and 4.2 K a few exciton lines are observed for single quantum wells grown with a few minutes growth interruption at heterointerfaces under As4 pressure. The energy splittings of these peaks well correspond to monolayer well width fluctuations. The full widths at half maximum (FWHM) of these peaks are much narrower than those of peaks obtained from no growth interruption samples. Wide FWHM with no growth interruption sample comes from the small lateral extent of fluctuations comparable to the exciton diameter. Monolayer growth steps are much diminished after a few minutes growth interruption due to the migration of surface atoms.