Strained InGaAs ridge quantum wires structure grown by molecular beam epitaxy on nonplanar substrate

Abstract

A new type of strained InGaAs/GaAs ridge quantum wires (QWRs) structure has been proposed and fabricated firstly by MBE growth on patterned substrate. High resolution scanning electron microscope studies show that these ridge structures were formed with top and side faces. The photoluminescence measurements indicated that the lateral quantum confinement effects of the ridge-QWRs caused a blue-shift of the quantum confined energy, which agrees with the approximate calculations for the strained-ridge-QWR structure using Kronig-Penney model. This strained-ridge-QWRs consists of three aspects of lateral confinement effects. Firstly the thickness of ridge quantum wells on the ridge top is larger than that on the side surfaces; secondly the Indium concentrations on the ridge-top region is higher than that on the side region; thirdly the strain effects lead to a larger energy gaps in side plane than that in the ridge top. The above three factors were incorporated to enhance the confinement effects on the lateral motion of carriers in strained ridge QWRs.