Measurement of absolute Al concentration in Al_xGa_1-xAs

A technique has been developed to measure the absolute Al concentration x in AlxGa1-xAs. The technique involves simultaneous measurements of the 27Al(p, γ)28Si resonant nuclear reaction and Rutherford backscattering (RBS), and comparisons with an AlAs reference sample. A detailed description of the experimental procedure is given. Samples analyzed in this study were prepared by LPE and MOVPE growth on GaAs substrates, with epitaxial layer thicknesses in the range 1-3 μm and Al concentrations in the range 0.10 < x < 0.85. Measurements of x with an absolute error < 0.02 were obtained. Factors limiting the precision obtainable with this technique are discussed. © 1987 Elsevier Science Publishers B.V. (North-Holland Physics Publishing Division) All rights reserved.