Extremely flat growth-interrupted InAlAs surface grown on a <f>(4 1 1)A</f>-oriented InP substrate by molecular beam epitaxy

We investigated flatness of growth-interrupted InAlAs and InGaAs surfaces using <f>In0.53Ga0.47As/In0.52Al0.48As</f> quantum wells (QWs) with well widths (<f>Lw</f>) of 0.6–<f>12 nm</f> grown on a <f>(4 1 1)A</f>-oriented InP substrate by molecular beam epitaxy. In the <f>(4 1 1)A</f> QWs with growth interruption (GI) at the InGaAs/InAlAs interface (InAlAs surface), full width at half maximum (FWHM) of a photoluminescence peak of the 1.2-nm-thick InGaAs well was as narrow as <f>15.6 meV</f>, which was almost the same as that of the corresponding well without GI (<f>14.4 meV</f>). On the other hand, the FWHM of the <f>(1 0 0)</f> QWs with GI at the InAlAs surface was <f>24.1 meV</f> (<f>Lw=1.2 nm</f>), which was 55% larger than that of the <f>(4 1 1)A</f> QWs with GI at the InAlAs surface. This result indicates that the effectively atomically flat interfaces [<f>(4 1 1)A</f> super-flat interfaces] are successfully kept in spite of introducing GI, while GI makes the <f>(1 0 0)</f> interface much rough. [Copyright &y& Elsevier]