Transitions of epitaxially lifted-off bulk GaAs and GaAs/AlGaAs quantum well under thermal-induced compressive and tensile strain

Abstract

Low temperature photoluminescence and reflectance measurements on epitaxially lifted-off (ELO) bulk GaAs and GaAs/AlGaAs multiple quantum wells (MQWs) bonded to Si and MgO substrates are reported. Photoluminescence measurements indicate no strain at room temperature for the ELO bulk GaAs film but show biaxial strain at 10 K. Si-bonded films undergo tensile strain, while films with MgO host substrates experience compressive strain. Reflectance measurements at 10 K show that light hole band is closer to the conduction band for the tensile strained film. In GaAs MQW ELO films, the separation of the heavy hole and light hole band is reduced in tensile strained films by 4.7 meV, corresponding to a strain ε=−0.7±0.05×10−3 and stress X=0.9±0.05 kbar (90±5 MPa). For compressively strained films, this separation is enhanced by 3.9 meV, equivalent to a strain ε=0.6±0.05×10−3 and X=0.8±0.05×10−3 kbar (80±5 MPa). The findings demonstrate that ELO is an effective technique to introduce tensile and compressive strain in GaAs heterostructures and is appropriate for strain-related spectroscopy.