Comprehensive study of AlGaAs/GaAs heterostructures grown by MBE: Structural and compositional analysis

Abstract

AlGaAs/GaAs heterostructures having different thicknesses of AlGaAs layers have been grown by Molecular Beam Epitaxy. Detailed Structural characterization of these structures has been performed and discussed in this report. AlGaAs layer thicknesses have been measured by an electrochemical Capacitance-Voltage profiler by etch profiling and confirmed by field emission scanning electron eicroscopy and RADS-fitted data of high-resolution X-ray diffraction scans. Compositional analysis have been performed by photoluminescence and high-resolution X-ray diffraction and discussed here. The Poisson's ratio of AlGaAs layers has been calculated by considering linear dependence on Al mole fraction to get the estimate of the critical thickness of the AlGaAs layer. Out-of-plane strain has been calculated from the triple axis symmetric (ω-2θ) diffraction profile and compared with RADS-itted data.