Much improved flat interfaces of InGaAs∕AlAsSb quantum well structures grown on (411)A InP substrates by molecular-beam epitaxya)

In0.53Ga0.47As∕AlAs0.56Sb0.44 quantum well (QW) structures were grown on a (411)A oriented InP substrate by molecular-beam epitaxy (MBE). Photoluminescence (PL) spectra at 12K indicated that interface flatness of a 2.4nm thick In0.53Ga0.47As QWs on the (411)A InP substrate, which can be utilized for 1.55μm range all-optical-switching devices using intersubband transition (ISBT), is much superior to that of QWs simultaneously grown on a conventional (100) InP substrate over the whole range of the growth temperature (Ts=480–570°C). The best value of full width at half-maximum of a PL peak (12K) from the 2.4nm thick In0.53Ga0.47As∕AlAs0.56Sb0.44 QW grown on the (411)A InP substrate at 570°C was 36meV, which is much smaller than the best value previously reported (58meV) for similar (100) In0.53Ga0.47As∕AlAs0.56Sb0.44 QWs. This result indicates that MBE growth of In0.53Ga0.47As∕AlAs0.56Sb0.44 QWs on the (411)A InP substrate significantly improves their interface flatness and 1.55μm range In0.53Ga0.47As∕AlAs0....