Lateral modulations in zero-net-strained GaInAsP multilayers grown by gas source molecular-beam epitaxy

Abstract

Compressive GaInAsP multiple quantum wells (MQW) grown by gas source molecular-beam epitaxy present altered structural and optical characteristics when tensile GaInAsP barriers are used instead of lattice-matched ones. An alternate tensile/compressive GaInAsP MQW has been examined by transmission electron microscopy. A strong lateral modulation of thickness, strain, and probably chemical composition was shown. This modulation exhibits pronounced anisotropy, with a periodicity of about 50 nm along the [110] direction. Although its origin is not fully accounted for yet, it seems to allow partial elastic relaxation of tensile layers. Based on this analysis, a schematic description of distortion modulation is proposed.