Lattice-matched InxGa1−xAs/InxAl1−xAs quantum wells (x= 0.18 and 0.19) grown on (4 1 1)A- and (1 0 0)-oriented InGaAs ternary substrates by molecular beam epitaxy

High-optical quality lattice-matched InxGa1−xAs/InxAl1−xAs quantum wells (QWs) with indium contents of x=0.18–0.19 have been successfully grown on (411)A- and (100)-oriented InGaAs ternary substrates by molecular beam epitaxy. Strong photoluminescence (PL) with a narrow linewidth was observed from both (411)A and (100) QWs at 12K. The peak energy of PL from QWs had a good correlation with the calculated exciton emission energy based on the band parameter of the InGaAs well layers and InAlAs barrier layers. The result indicates that the (411)A and (100) InGaAs/InAlAs QWs on InGaAs ternary substrates have 0.2eV larger energy gap difference between their well and barrier materials than GaAs/AlAs QWs on GaAs binary substrates or InGaAs/InAlAs QWs on InP binary substrates. In addition, the (411)A In0.18Ga0.82As/In0.18Al0.82As QWs had a narrower PL linewidth than (100) QWs indicating that smoother interfaces were realized in the (411)A QWs.