Lattice-matched In xGa 1− xAs/In xAl 1− 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

Abstract

High-optical quality lattice-matched In x Ga 1− x As/In x Al 1− x As quantum wells (QWs) with indium contents of x=0.18–0.19 have been successfully grown on (4 1 1)A- and (1 0 0)-oriented InGaAs ternary substrates by molecular beam epitaxy. Strong photoluminescence (PL) with a narrow linewidth was observed from both (4 1 1)A and (1 0 0) QWs at 12 K. 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 (4 1 1)A and (1 0 0) InGaAs/InAlAs QWs on InGaAs ternary substrates have 0.2 eV 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 (4 1 1)A In 0.18Ga 0.82As/In 0.18Al 0.82As QWs had a narrower PL linewidth than (1 0 0) QWs indicating that smoother interfaces were realized in the (4 1 1)A QWs.