Abstract
Photoreflectance (PR) and photoluminescence (PL) spectroscopies were employed in the characterization of molecular beam epitaxially grown GaAs/AlGaAs quantum wells grown on nominally flat (100) oriented and (100) misoriented GaAs substrates. Four quantum wells with nominal thickness of 100, 75, 50 and 25 Å were grown employing different temperatures between 600 and 650° C and growth rates of 0.5 and 1 µ m/h. Room temperature PR allowed us to obtain the actual aluminum composition (x=0.27), and obtain the magnitude of the interfacial electric field ( ∼106 V/cm). An evaluation of the abruptness of the quantum well interfaces was done from the analysis of PL and PR spectra in terms of the finite quantum well theory. The overall results clearly indicated that the step-flow growth mode on the misoriented substrate produced superior crystallinity of the heterostructures. In the case of growth on flat substrates higher temperatures and slower growth rates gave broader interfaces and thinner wells.
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