Abstract | Although the AlₓGa₍₁₋ₓ₎As alloy system has been extensively investigated, there are still considerable uncertainties in measuring the value of x. Here a new AlₓGa₍₁₋ₓ₎As calibration structure, grown by molecular beam epitaxy, has been used to establish unambiguous alloy compositions. Such ‘standard’ AlxGa(1 − xAs layers were measured by high-resolution X-ray diffraction, photoluminescence, and Raman spectroscopy to determine the compositional variations of the measured physical parameters. The formulae provided give a reliable calibration base for other characterization tools. A detailed analysis of the X-ray results shows that Vegard's law does not hold for the variation of the AlₓGa₍₁₋ₓ₎As lattice constant with x. |
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